Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE FOR THE DIRECT MANUAL EXAMINATION
OF A PATIENT IN A NON-CONTIGUOUS LOCATION
Field of the Invention
This invention relates to medical devices that transmit tactile information
from a
remote location to an individual and, in particular, to devices that assist in
the
examination of a patient at a location remote from the location of a medical
examiner.
Background of the Invention
Computer technology and the enhanced ability for individuals to communicate
via
the Internet and other wide area networks have greatly altered our society.
These
communications platforms have allowed for the effective and efficient
worldwide transfer
of data as well as accessibility of this information to the general public.
The way in
which people communicate, exchange information, and transact business is being
substantially affected by these developments. Traditional business practices
are being
expanded such that any business with a computer and Web site has potential
access to
any consumer in the world with a computer. Each individual business now has
essentially a worldwide customer base. While many businesses are capitalizing
on these
current trends, the health care industry is one notable exception that is
substantially
lagging.
The health care environment is extremely complex. While third party and
government payers and players in this arena have applied pressure to patients,
hospitals,
and physicians in order to "standardize" health care issues into predictable
business
models, this has been a difficult task to date. The uniqueness of each
individual and the
underlying basic characteristics of biological organisms, in themselves,
preclude
medicine from ever being an exact science which can be accurately predicted in
all
respects. This variability among patients, their diseases, their individual
manifestation of
similar diseases, and physician skill, training, and treatment practices all
contribute to the
difficulty in standardizing medical information collection, data storage,
treatment
algorithms, outcomes, and business modeling,
Medical practice is also a very unique type of personal service. A sick
patient
interacts with a unique skilled professional with the expectation of improving
his or her
health condition or alleviating suffering. The underlying physician-patient
encounter is in
actuality a complex data gathering interaction which is processed by the
physician, who
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then develops an optimal diagnosis and treatment plan. The input data from the
physician-patient encounter comes from a variety of sources which include the
physical
examination of the patient, laboratory tests, and radiological imaging
studies. The most
important source of input information is often the actual physical examination
of the
patient. The physical examination consists of the transfer of personal
historical
information from the patient to the physician, a review of the patient's
current
medications, and a direct visual and manual examination of the patient's body
by the
physician.
The manual examination of the patient's body includes applying gentle hand
pressure along various parts of the abdomen, chest, and extremities in order
to determine
the body's response to direct manipulation. Inflammatory processes such as
infections,
abscesses, thromboses (clots), hollow or solid organ perforations, or
fractures will yield a
pain response with an increase in resistance in order to "guard" or protect
against the
noxious applied stimulus. Tumors or organ enlargement may be detected by
resistance
changes detected below an otherwise normal skin surface, analogous to
perceiving a
stone trapped in one's shoe. Fluid within the abdomen (ascites) can also be
detected by
applying hand pressure at one end of the abdomen and detecting the resultant
fluid wave
at an opposite location within the same cavity.
An expertly performed history and physical examination will yield a correct
diagnosis with approximately 90% accuracy. In most circumstances, the
laboratory and
radiological imaging data provide confirmation of the diagnosis as well as
adjunctive
detail regarding the patient's condition. In the general sense, the physician
functions as a
computer by collecting all of the available input data from the various
sources, processing
that information with respect to the physician's personal knowledge or
reference base, and
establishing a list of likely diagnostic possibilities based on the input
information. The
physician then recommends a plan of treatment which is expected to improve the
patient's
health condition.
A portion of the data required to make an accurate medical diagnosis can be
exchanged between the patient, laboratory, radiology, and physician using a
variety of
communications methods without the need for direct face to face contact
between the
communicating entities. The current communications revolution has allowed for
the
exchange of historical information, laboratory data, telemetry, and
radiological studies
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via telephone, pager, fax, e-mail, and video. These advantages have benefited
all
types of businesses, and medicine is no exception. There is, however, one
unique
piece of the data gathering process specific to medicine -- the direct manual
examination of the patient's body by the physician -- which currently is not
amenable
to remote data acquisition.
Summary of the Invention
In accordance with one aspect of the invention, there is provided a device for
remotely conducting a direct manual examination of a patient. The device
includes a
hand control unit having a first sensory modulation subunit, the first-sensory
modulation subunit being capable of both generating a first output signal
related to an
applied force, and generating a force or displacement in response to a
received first
input signal. The device also includes a patient examination module located
remotely
from the hand control unit, the patient examination module having a plurality
of
second sensory modulation subunits disposed in individual cells in a flexible
pad that
is adapted to be attached to the patient. The second sensory modulation
subunits are
capable of both generating a second output signal related to an applied force,
and
generating a force or displacement in response to a received second input
signal. The
device further includes a computer and a selecting mechanism for selectively
associating the first sensory modulation subunit to any of the second
plurality of
sensory modulation subunits. The patient examination module and the hand
control
unit are operatively linked to the computer such that the first output signal
from the
first sensory modulation subunit includes the second input signal to the
associated
second sensory modulation subunit. The second output signal from the
associated
second sensory modulation subunit comprises the first input signal to the
first sensory
modulation subunit.
The first sensory modulation subunit may be a slab of elastic material having
an embedded pressure transducer wherein the slab of elastic material may be
attached
to a variable pressure producing device.
The variable pressure producing device may be a single channel piston-type
variable resistor.
The selecting mechanism may be a tracking ball and a button.
The hand control unit may have a hand-shaped upper surface and may further
include a forward portion and a rearward portion, the forward and rearward
portions
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being slidably connected whereby the hand control unit may be adjusted to
accommodate different-sized hands.
The hand-shaped upper surface may include four fingertip portions, each
including a third sensory modulation subunit substantially identical to the
first sensory
modulation subunit.
The patient examination module may include the flexible pad and the flexible
pad may include a plurality of expandable cells attached to a backing. The
patient
examination module may also include the second sensory modulation subunits and
the
second sensory modulation subunits may include pressure transducers attached
to the
plurality of expandable cells. The pressure transducers may be adapted to
generate the
second output signal that is directly related to an interface pressure between
the pad
and the patient. The patient examination module may further include a fluid
media
that may be selectively directed to some of the plurality of expandable cells
to
produce a desired pressure within the expandable cells.
The fluid media may be air.
The fluid media may be an hydraulic fluid.
The device may further include a plurality of electrically actuated valves,
each
valve located between one of the plurality of expandable cells and a
pressurized fluid
media reservoir.
The device may further include a command control box having a controller
electrically connected to the plurality of valves and to the plurality of
pressure
transducers.
In accordance with another aspect of the invention, there is provided a device
for remotely examining a patient. The device includes a hand control unit
having a
first sensory modulation subunit, the first sensory modulation subunit being
capable
of both generating a second output signal related to an applied force, and
generating a
force or displacement in response to a received first input signal and the
hand control
unit being connected to a first computer having a first data communications
system at
a first location. The device also includes a patient examination module having
a
plurality of second sensory modulation subunits disposed in individual cells
in a
flexible pad that is adapted to be attached to a patient. The second sensory
modulation
subunits are capable of both generating a second output signal related to an
applied
force, and generating a force or displacement in response to a second received
input
signal. The patient examination module is connected to a second computer
having
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a second data communications system at a second location. The device further
includes a selecting mechanism for selectively associating the first sensory
modulation subunit with any of the plurality of second sensory modulation
subunits.
The first data communications system is operably configured to interface with
the
second data communications system such that the first computer can communicate
with the second computer. The first output signal from the first sensory
modulation
subunit includes the second input signal to the associated second sensory
modulation
subunit, and the second output signal from the associated second sensory
modulation
subunit includes the first input signal to the first sensory modulation
subunit.
The first data communications system and the second data communications
system may interface over standard telephone lines.
The first data communications system and the second data communications
system may interface over a global telecommunications system.
The first data communications system and the second communications system
may interface over a fiber optic network.
Brief Description of the Drawings
The foregoing aspects and many of the attendant advantages of this invention
will become more readily appreciated as the same become better understood by
reference to the following detailed description, when taken in conjunction
with the
accompanying drawings, wherein:
FIGURE 1 illustrates a preferred embodiment of the system of the present
invention in use, showing a physician examining a patient who is located
remotely
from the physician.
FIGURE 2 is a plan view of a hand control unit in accordance with the present
invention.
FIGURE 3 is a schematic cross-sectional view of the hand control unit of
FIGURE 2.
FIGURE 4 is a cross-sectional sketch of a sensory modulation subunit for the
hand control unit shown in FIGURE 3, in accordance with the present invention.
FIGURE 5 is a front view of a preferred embodiment of a patient examination
module for examination of a patient's torso, in accordance with the present
invention.
FIGURE 6 is a cross-sectional view of a cell from the patient examination
module shown in FIGURE 5
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FIGURE 7 is a front view of a second preferred embodiment of a patient
examination module for examination of a patient's torso, in accordance with
the present
invention.
FIGURE 8 is a cross-sectional view of a cell from the patient examination
module
shown in FIGURE 7.
FIGURE 9 is a general process flow diagram of a preferred embodiment of the
present invention.
FIGURES 10A-10C present a flow diagram detailing the functions of the software
controlling the preferred embodiment shown in FIGURE 1.
Detailed Description of the Preferred Embodiment
The device disclosed herein enables a physician to perform a direct physical
examination of a patient's body without direct physical contact or proximity
between the
patient and the physician. This allows physical data of the type normally
acquired from
direct manual contact between the patient and the physician to be gathered and
transmitted via conventional global communications systems. To date,
"telemedicine" or
the exchange of medical information between a patient and physician for 'the
purpose of
rendering a diagnosis and treatment plan, can only proceed to a point, and if
the physical
exam findings become critical in the decision making process, the patient is
advised to
actually see their personal physician or present to an emergency room where a
physician
can perform a physical examination. This inability to acquire physical data
remotely and
transfer it reliably to a physician in another location is a barrier to the
evolution of
medical 'practice and the ability of medicine to capitalize on the
effectiveness and
efficiencies that other business are enjoying with respect to the advances in
global
communications platforms and a potential global consumer audience.
As used herein, the following terms shall have the meaning indicated:
Sensory modulation subunit means any device capable of (1) detecting a force
applied to the device and generating an output signal related to the detected
force; and
(2) receiving an input signal and generating a force and/or displacement
related to the
received input signal.
Hand control unit, or HCU, means any device adapted to contact or receive a
portion of a user's body-such as a user's hand-and having sensory modulation
subunits
that can be accessed by the received user's hand.
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Patient examination module, or PEM, means any device adapted to receive a
portion of a person's (or other biological organism's) anatomy, and having
sensory
modulation subunits that are adjacent to the received portion of anatomy. PEMs
may be
used in accordance with the present invention for patient examination, but the
term PEM
is to be understood to also encompass devices adapted for tactile sensing of
anatomy for
other purposes, or for tactile sensing of other objects or substances.
Referring now to FIGURE 1, the present invention, for the remote acquisition
and
transmission of physically derived medical data, includes three general parts:
the hand
control unit 100 (HCU), the patient examination module 200 (PEM), and computer
software to control the acquisition, calibration, transfer, and translation of
the physical
data between the physician (through the HCU) and the patient (through the
PEM). The
present invention allows a physician to apply hand pressures to the HCU 100
that are
transmitted to a remotely situated patient and applied to selected portions of
the patient's
body through the PEM 200. The pressure response from the patient's body is
transmitted
back to the physician, thereby simulating direct contact between the physician
and
patient.
Hand Control Unit (HCU)
The HCU 100, shown in FIGURE 2, has a molded plastic shell 101 formed in the
shape of an actual hand. The advantages of this type of construction are that
it is
lightweight, easy to manufacture, durable, and impact resistant. Other
materials such as
wood, paper, aluminum, stone, PlexiglasTM, or as of yet to be developed
materials could
also be used for device construction. The HCU 100 is shaped to accommodate a
portion
or preferably the entire inner surface of the human hand, having a palmar
surface 102
including a proximal palm portion 108 and a distal palm portion 107,
fingertips 106, and
a thumb portion 105. An objective of any design configuration is to provide a
comfortable contact surface between sensory and motor portions of the user's
hand and
the HCU 100. In the preferred embodiment, the HCU 100 has a slight central
rise in the
palmar surface 102. The periphery of the palmar surface 102 has a slight
depression with
respect to a border 104 of the HCU 100 to accommodate the user's hand resting
comfortably on the palmar surface 102. The slight palmar rise with respect to
the
position of the fingertips 106 and proximal palm portion 108 (such that the
level of the
user's knuckles will be higher than the other parts of the fingers and hand)
forms a broad
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based, pyramidal configuration. This design allows for maximum flexibility
with respect
to fingertips, distal palm, and proximal palm pressure application and
reception, device
control, and functionality. The HCU 100 allows for complete contact between
all parts of
the palmar surface of the user's palm and fingers with the palmar surface 102
of the
HCU 100. In the preferred embodiment, the shell 101 of the HCU 100 is formed
in two
laterally disposed segments lOla, 10 lb, with a transverse break 110 located
generally at
the location of the user's mid-pal mar crease. The two segments 101a, 101b,
are slidably
connected to permit relative longitudinal motion to allow for adjustments with
respect to
hand length in order to accommodate various hand sizes. Optionally, the HCU
100 could
include a "glove" component (not shown) where the whole hand is inserted into
a hand
control unit. This would allow for contact with the top (dorsal) hand surface
permitting
functions related to examination motions and sensory inputs derived from the
top surface
of the operator's hand.
Depressions or cavities 112, 114, 116, are provided in the fingertips 106,
distal
palm 107, and proximal palm portions 108, respectively. Within each depression
112,
114, 116, a pressure relay and reception sensory modulation subunit 140 is
housed, as
seen most clearly in FIGURE 3. The top of the sensory modulation subunit 140
consists
of a slab 142 of a pliable material such as silicon rubber or a soft plastic
matrix forming a
simulated skin surface. Other suitable materials may include other natural or
artificial
biomaterials (artificial, simulated, cultured, or engineered skin cells or
substitutes) for this
"skin" contact surface. The size of each slab 142 will vary with the size of
each
depression 112, 114, 116 in the HCU 100. In general, there are fingertip-sized
sensory
modulation subunits 140 for each of the fingertip 106 areas of the device, a
proximal
palm-sized subunit 140, and a distal palm-sized subunit 140 for the proximal
palm 108
and distal palm 107 portions, respectively. To increase the sensitivity and
functionality
of the HCU 100, each module could be multiply subdivided and each depression
could
include a collection of smaller functional subunits based on the general
subunit
description below.
Referring now to FIGURE 4, the sensory modulation subunit 140 includes a
one-way single channel pressure transducer 144 embedded within the slab 142 of
simulated skin. The working surface or pressure receiving face 145 of the
pressure
transducer 144 is oriented upward, i.e., in the direction facing the palmar
surface of the
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user's hand. The pressure transducer 144 is oriented such that pressure
applied by the
user is applied to the working surface 145 of the pressure transducer 144,
while pressure
or force applied from behind the transducer 144 is not sensed directly. In the
preferred
embodiment, a single pressure transducer 144 is located within each fingertip
106, while
each palmar portion 107, 108, is subdivided into two pressure zones. Wires or
other
appropriate connecting mechanism (not shown) provide signal access to and from
the
pressure transducer 144.
The simulated skin slab 142 with the embedded single channel pressure
transducer 144 is mounted on a thin support platform 146, preferably made of
metal or
plastic. Attached to the undersurface of the support platform 146 is a linear
actuator, a
variable force-producing device such as a single channel piston-type variable
resistor, or
other variable pressure-producing device 148. The linear actuator, or variable
pressure-
producing device 148, referred to herein as the "piston resistor," may be
embodied in a
number of ways that are known in the art, including devices that produce a
variable force
by electrical, mechanical, pneumatic, or hydraulic processes. A representative
sampling
of such devices are described, for example, in U.S. Patent No. 5,631,861 to
Kramer,
illustrated in FIGURES 8a-m thereof, and referred to therein as a "finger tip
texture
simulator." In the preferred embodiment of the present invention, magnetically
motivated
devices are utilized. The piston resistor 148 provides counter pressure or a
resistance
force against the undersurface of the simulated skin slab 142 dependent upon
the
response signal derived from the patient examination module 200 (described
below). The
slab 142, transducer 144, support platform 146, and piston resistor 148 are
disposed
within the depressions 112, 114, 116, in the HCU 100. Holes 150 are provided
within
each depression 112, 114, 116, to accommodate insertion of the free end of the
piston
resistor 148. The hole 150 depth is selected such that the support platform
146 is slightly
elevated from the depression lower surface and therefore the only resistance
felt by the
user is that of the simulated skin slab 142 itself.
Various types of pressure transducers are known in the art and suitable for
use in
the present invention. For example, and without limiting the scope of the
present
invention, U.S. Patent No. 6,033,370 issued to Reinbold et al., discloses a
capacitative
pressure force transducer having a polyurethane foam dielectric sandwiched
between two
conductor layers. A similar device is disclosed by Duncan et al. in U.S.
Patent
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No. 4,852,443, wherein compressible projections on the capacitor electrodes
are disposed
on either side of a dielectric sheet. A pressure transducer based on variable
resistance
components is disclosed in U.S. Patent No. 5,060,527 by Burgess.
Referring again to FIGURE 2, the corresponding thumb portion 105 of the
HCU 100 houses a button 152 for controlling and selecting functions and
options related
to the computer software (e.g., a mouse click control or other input device).
The under
surface of the HCU 100 supports a tracking ball 154 to allow for computer
selection
functions, and two-dimensional coordinate location of the HCU 100 in space as
related to
the patient through the PEM 200. It will be apparent to one of skill in the
art that the
button 152 and tracking ball 154 provide the basic functionality of a computer
mouse and
can be used to selectively interact with the computer in a familiar and well-
known
manner. It will also be apparent that other types of selecting mechanisms
could be
utilized, including touch-sensitive pads and optical systems. The HCU 100 is
also linked
to a signal processor 130 and an analog-to-digital/digital-to-analog signal
converter 132.
The HCU 100 acts as the interface or contact point between the physician and
the
remote patient. The HCU 100 receives the mechanically applied pressure signal
generated by the physician's hand and converts it to an electrical signal via
the pressure
transducer 144, while simultaneously converting the incoming electrical signal
derived
from the pressure response at the patient examination module 200 into a
resistance signal
that is applied to the piston resistor 148 mounted against the support
platform. This
ability of the sensory modulation subunit 140 to both "sense" the input
pressure applied
by the user and simultaneously provide a direct resistance feedback response
to the user
simulates the actual events that occur when one presses their hand against
another object.
Higher degrees of resistance sensed by the PEM 200 (actual patient response)
in response
to the direct pressure applied to the patient (as determined by the input
pressure from the
HCU 100) is relayed back to the HCU 100 and fed back to the physician through
the
piston resistor 148. Increasing resistance sensed by the PEM 200 will
correspond to
increasing force being applied to the undersurface of the support platform
146. This
translates into a sensation of greater resistance or a "lack of give" to the
simulated skin
slab 142. This feedback resistance can be perceived by the user as the direct
response
from the patient to the forces applied by the physician.
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The HCU 100 could optionally incorporate single or multiple multi-channel
pressure transducer/resistor devices and/or the absolute change in resistance
could be
translated back to the physician's hand via the hand controller unit. The
thumb
portion 105, currently used for software command functions, could
alternatively house a
sensory modulation subunit 140. The ability to integrate thumb motions into
the
examination process as well as having sensory input back to this part of the
hand would
allow for expanded functional capacity and sensitivity of the HCU 100. The
most
complex embodiment of an HCU would include full contact with every portion of
the
operator's hand, and a large number of sensory modulation subunits 140 applied
throughout the HCU. The number of subunits 140 is limited only by the ability
to
miniaturize these bidirectional pressure transducing devices. A large number
of sensory
modulation subunits would allow the user to produce and receive mechanical and
sensory
inputs from every portion of the operator's hand.
Patient Examination Module (PEM)
Referring now to FIGURES 5 and 6, PEM 200 consists of a pad or pad-like
structure 202 made of soft, semi-compliant material such as nylon, rubber,
silicon, or a
soft plastic substrate. The entire pad 202 is solid, preferably with
viscoelastic properties
similar to the simulated skin slab 142 of the HCU 100. The pad 202 is
subdivided into a
basic structural unit called a cell or cell zone 204. The overall size of the
pad 202, as well
as the number of cells 204 within the pad 202, will vary depending upon the
particular
application. Each cell zone 204 corresponds to an area within the pad 202,
preferably
similar in size to the corresponding sensory modulation subunit 140 of the HCU
100. As
shown in FIGURE 6, a single channel pressure transducer 244 is mounted within
each
cell 204, oriented with the working/receiving surface 245 facing in the
direction of the
patient. The preferred pad 202 is a continuous gel-type structure 242 with a
multitude of
embedded pressure transducers 244. The back surface 206 of the pad 202
includes a
flexible, semi-rigid sheeting. The currently preferred material for the back
surface 206 is
a plastic or polymer substance that will maintain a rigid backing to the cell
zones 204, yet
allow for some bending to accommodate applications to a variety of body sizes.
More
solid materials such as metal, wood, or composite materials could also be used
as long as
it provided a solid backing structure and allowed for articulation around
various
contoured surfaces of the body. A linear actuator, comprising a single channel
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piston-type variable pressure producing sensory modulation subunit 240 is
attached to the
undersurface of a thin support platform 246, preferably made of metal or
plastic. The
support platform 246 is preferably similar to the size of the fingertips 106
in the
HCU 100. Centered directly below each pressure transducer 244 generally
located at the
interface between the cell 204 and backing 206, a piston-type variable
pressure producing
device 248, or similar linear actuator is embedded within the backing 206,
oriented
beneath the center of the support platform 246 below the pressure transducer
244.
The examination pad 202 is applied directly over the portion of the patient's
body
surface to be examined and held in place, for example, by a nylon loop-and-
hook type of
closure 250. The nylon loop-and-hook closure 250 would provide adjustability
and allow
for application to a wide variety of body shapes and sizes. The pad 202 could
also be
fashioned into vests for chest applications; binders for abdominal
applications; sleeves,
gauntlets, or gloves for upper extremity applications; pant legs or boots for
lower
extremity applications; or small strips for small applications such as fingers
or toes.
While the preferred embodiment of a PEM is constructed as a stationary
positioned pad, a
mobile sensing unit that the patient, other personnel, or a robotic guide
moves over a
surface of the patient's epidermis or within a body cavity, is also within the-
scope of the
invention.
In one preferred embodiment, the PEM 200 is attached to a command control
box 300 via an electrical umbilical 302. In the preferred embodiment, the
command
control box 300 includes a power supply 304, a small central processing unit
(CPU) 306,
a signal processor 308, digital-to-analog converter 310, and a communications
system 312, The command control box 300 receives and transmits data to and
from the
PEM 200, and links the PEM 200 to the physician's HCU 100. The power supply
304
preferably allows for both the ability to work from alternating current
(household or
industrial) or direct current (battery operations). While an umbilical 302 is
illustrated,
other data links such as a wireless data link are also within the scope of the
invention.
The communications system 312 of the preferred embodiment includes an internal
modem (not shown) which would allow a physician's computer 160 located near
the
HCU 100 to connect to a remote computer 260 located near the PEM 200. Other
communication systems are also possible, including systems based on:
(1) light-based/optical based communications including fiber-optic cable
channels and
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non-fiber, light based methods of data/voice/visual signal transmission; (2)
wireless
communications including but not limited to radio frequency, ultrahigh
frequency,
microwave, or satellite systems in which voice and/or data information can be
transmitted
or received; and (3) any future methods of voice or data transmission
utilizing any
currently unused mediums such as infrared light, magnetism, other wavelengths
of visible
and non-visible radiation, biornaterials (including biorobots or viral
vectors), or
atomic/subatomic particles. Optimally, the command control box 300 is
connected to the
pad 202 through a flexible umbilical 302 for considerations of reduced weight
being
applied directly to the patient, size limitations, and possibly safety (i. e.,
reduced RF or
microwave radiation exposure from communications/data transmissions). The
umbilical 302 also connects the pressure transducers 244 and variable pressure
producing
devices 248 within the sensory modulation subunits 240 to the power supply
304.
Other device configurations could incorporate single or multiple multi-channel
pressure transducer/resistor devices and the absolute change in resistance
could be
translated back to the user's hand via the HCU 100. In an attempt to increase
the
sensitivity and functionality of the PEM 200, each cell zone 204 could be
multiply
subdivided and a large number of sensory modulation subunits applied
throughout the
PEM 200. The number of functional subunits would only be limited by the
ability to
miniaturize these bidirectional sensory modulation subunits. A large number of
small
sensory modulation subunits would provide the ability to produce and receive
mechanical
and sensory inputs from every portion of the PEM 200.
A second embodiment of the PEM 400 utilizes a pneumatic pressurizing medium
or hydraulic pressurizing medium as shown in FIGURE 7 and FIGURE 8, rather
than the
electromechanical structure described above. In this second embodiment, the
PEM 400
consists of a pad 402 or pad-like structure made of soft, semicompliant
material such as
nylon, rubber, silicon, or a soft plastic substrate. The pad 402 is subdivided
into a
plurality of cells 404. The overall size of the pad 402, as well as the number
of cells 404
within the pad 402, will vary by device model and application. Each cell 404
is designed
as an air- and water-tight hollow chamber 416 with one dual function
inlet/outlet line 410
and one valve 414 to allow inflow
and outflow of a pressurizing medium, such as air, water, hydraulic fluid, or
an
electrochemical gel, and a single pressure transducer 444. The pressure
transducer 444 is
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a single channel transducer similar to the transducer 144 described above for
the
HCU 100. The pressure transducer 444 is mounted within the material sheet
applied
directly to the patient's body surface. The open cell structure would
therefore be behind
the pressure transducer 444. The receiving surface 445 of the transducer would
be
oriented facing in the direction of the patient.
The pad 402 is applied directly over the portion of the patient's body surface
to be
examined, and is held in place, for example, by a loop-and-hook type of
closure 250. The
loop-and-hook closure 250 provides adjustability and allow for application to
a wide
variety of body shapes and sizes. The pad 402 could also be fashioned into
vests,
binders, sleeves, gauntlets, gloves, pant legs, boots, or small strips for
small applications
such as fingers or toes, as previously described. The outer surface of the pad
402 could
also include a heavy reinforcing layer (i.e., lead, metal, or plastic) to
provide added
stability or counter pressure if required. The inlet/outlet line 410 for each
cell 404 is
connected to a pumping mechanism which would include a pump (not shown) and a
pressurizing reservoir 418 for housing the pressurizing medium. An intervening
valve 414 is placed along the inlet/outlet line 410 between the pressure
reservoir 418 and
each cell 404. The PEM 400 is attached to a command control box 300 via an
umbilical 302 as previously described.
Preferably this control section of the PEM 400 is disposed away from the
patient
for considerations of reduced weight being applied directly on the patient,
size limitations
if the pack is placed on a small section of the body such as a limb or finger,
or possibly
safety (i.e., reduced RF or microwave radiation exposure from
communications/data
transmissions). The specifications and functions of the command control box
300 are
described above. The umbilical 302 also connects the pressure transducers 444
and the
power supply 304, as well as the inlet/outlet lines 410 and valve 414 for the
pressurizing
medium.
Depending upon the specific HCU 100 design, the pump and pressurizing
reservoir 418 could be contained both together in the command control box 300
section,
together on the PEM 400 itself, or in either area independent of one another.
A PEM 400 utilizing air as a pressurizing medium would utilize a semi-closed
circuit design. In the preferred embodiment, the pumping mechanism draws air
from
outside the unit into a single pressurizing reservoir 418 applied to the back
of the
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pad 402. The pressurizing reservoir 418 is generally the same size as the pad
402.
Valves 414 are located at multiple positions within the pressurizing reservoir
418
corresponding to underlying cells 404. The pressurizing reservoir 418 is
therefore in
direct communication with each pressure cell 404 via the intervening valve
414. A
pressure regulating circuit (not shown) is integrated into the pressurizing
reservoir 418 in
order to sense internal chamber pressure, and relay that information back to
the command
control box 300 in order to ensure appropriate chamber pressure. After the
appropriate
cells 404 are activated, the desired pump chamber pressure achieved
(corresponding to
the appropriate applied pressure signal from the HCU 100), and the resulting
patient
response signal is transmitted back to the HCU 100 via the command control box
300, the
pump vents the contents of the pressure chamber 416 back into the atmosphere
via the
pump. A PEM 400 utilizing a hydraulic pressurizing medium consists of a self
contained,
closed fluid system circuit.
The function of the PEM 400 is to "transmit" the pressure applied by the user
at
the HCU 100 directly to the patient and send the resultant resistance response
signal from
the patient back to the physician's HCU 100. Using the software and the
physician's
HCU 100, various segments of the body within the confines of the PEM 400 can
be
examined by "selecting" the appropriate overlying cells 404 to be pressurized.
The
software sends the appropriate command to open the valves 414 corresponding to
the
selected cells 404. The number of selected cells 404 corresponds to the area
of the
patient's body the physician wishes to "press on" to elicit the patient's
response to the
applied "hand" pressure. In addition, the physician can independently select
the cells or
area of the body from which the return pressure data can be sent back to the
user. While
in many circumstances the cells which are being pressurized will also be
sending the
return pressure data signals back to the physician's HCU 100, for some
examination
functions, it is optimal to pressurize one cell set and receive from a
different one.
It is also contemplated that a second HCU could be incorporated, configured to
accommodate the hand opposite the first HCU, wherein the physician could use
one hand
to apply pressure to one location on the patient (through the first HCU and
the PEM) and
receive a pressure response to the other hand from another location on the
patient
(through the second HCU).
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The computer software controls the commands for the various functions of the
physician HCU 100, PEM 200 or 400, system dynamics, and the communications
protocols. HCU 100 functions include cell selection functions to activate
those specific
cells or group of cells to be activated and the cells to transmit the
resultant return signals.
The software also allows for assignment of specific pressure response pads of
the
physician HCU 100 to be designated as send patches to transmit the physician's
pressure
signal as well as receive pads to transmit the patient data back to the
physician.
The spatial orientation of the physician's HCU 100 with respect to the
patient's
body is also tracked by the computer software. Movements of the HCU 100 can be
translated and sent to the PEM 200 or 400 to simulate movement of the hand
across the
patient's body. In addition, an anatomy database can be incorporated to
provide cross-
sectional anatomy and three-dimensional renderings of the specific body area
being
examined.
The software translates the physical pressure response applied by the
physician to
the HCU 100 into an electrical signal. Standardization, calibration, and real-
time
monitoring of the signal and signal strength are typical program functions.
The software
is also responsible for the transmission protocols for electrical signal
conversion and
transmission from the HCU 100 to the PEM 200 or 400, and vice versa.
Transmission
protocols include signal transmission over land-based and non-land-based
communications platforms. All pump and valve commands, including pump chamber
pressurization, calibration and conversion of the transmitted electrical
signal back into the
appropriate pressurization command correlating with a magnitude equivalent to
the actual
pressure applied at the hand control unit, and selected valve onloff status
are also
controlled by the device software.
FIGURE 9 represents the general process flow diagram of device functions for
both the electromechanical and pneumatic/hydraulic embodiments of the present
invention. Using the HCU 100, the physician selects the area of interest
underlying the
cells 204 or 404 to be activated corresponding to the area to be manually
examined.
Applying pressure to the HCU 100 via the sensory modulation subunits 140
generates
signals that are sent through a signal processor 130 and analog-to-digital
converter 132 to
a physician's computer 160 that, in turn, sends a computer command to activate
the
PEM's 200 or 400 sensory modulation subunits 240 or 440 underlying the area of
interest
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to which the HCU 100 pressure signals will be directed. The pressure
transducers 244
or 444 corresponding to the area of the patient the user wishes to "feel"
after the pressure
stimulus is applied are then activated. This command activates the receiving
cell's
pressure transducers 244 or 444 so the output signal can be transmitted back
to the
physician's HCU 100.
The physician then presses directly on the sensory modulation subunits 140 of
the
HCU 100 using any combination of fingertips, proximal palmar, and distal
palmar hand
surfaces (ranging from a single fingertip to the whole palmar hand surface) to
generate
the desired input pressure stimulus equal to the force he or she would
normally apply
during manual examination of a patient. The applied force will vary between
individuals,
circumstances, and the patient areas being examined. The pressure applied by
the
physician against the sensory modulation subunits 140 of the HCU 100 is sensed
by the
pressure transducer 144 and translated into an electrical output signal. The
electrical
output signal is sent to the signal processor 130 and the processed analog
electrical signal
is converted to a digital signal 132. The digital signal is then input to a
physician's
computer 160.
At the physician's computer 160 the software program is responsible for
software
commands for linked system pathways between the various send and receive
portions of
the HCU 100 and the PEM 200 or 400; calibration of the signal processors 130,
308,
pressure transducers 144, 244, 444, piston resistors 148, and variable
pressure-producing
devices 248 for both the user side and patient side equipment, and conversion
of the
HCU 100 electrical input signal into a corresponding PEM 200, 400 electrical
output
signal. If a pump system is used for the PEM 400, a pressure sensor (not
shown) within
the medium pressurizing reservoir 418 will be calibrated. The physician's
computer 160
transmits the PEM 200, 400 electrical signal and associated software commands
to the
remote computer 260 via the communication systems 312. Alternatively, the
patient side,
or remote side, may utilize a free standing command control box 300, located
near the
PEM 200 or 400. The digital pressure generating signal is then converted back
to an
analog electrical signal 310 by a digital to analog converter, post-processed
308, then
relayed to the appropriate, preselected pressure generating device of the PEM
200 or 400.
The PEM 200 or 400 then applies a directed force to the patient that is based
on the force
applied by the user or physician to the HCU 100.
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For the PEM 400, the software is responsible for receiving the incoming
electrical
signals from each active area of the HCU 100, assessing the corresponding
magnitude of
each of the input pressures applied to the various portions of the HCU 100 and
converting
this information into a specific pump command. The pressure commands are then
transmitted to either a remote computer 260 at the patient's remote location,
or directly to
the command control box 300 portion of the PEM 400 previously described. The
PEM 400 would then activate the pumping mechanism and pressurize the
pressurizing
chamber 418 in order to achieve an output pressure equal to the pressure
directly applied
by the physician to the HCU 100. The internal pressure of the chamber 418 is
monitored
by a pressure sensor that provides continuous feedback regarding the need to
continue or
discontinue pumping until the desired input pressure is achieved. The
pressurized
medium in the pressurizing chamber 418 is then transmitted to each of the
selected
cells 404 with open pressure valves 414 via the inlet/outlet line 410. The
pressurized
medium then flows into the selected cells 404 and increase the cell volume and
internal
cell pressure corresponding to the force applied by the physician at the HCU
100.
The downward force applied to the patient by either PEM 200 or 400 will elicit
a
counter-response from the patient ranging from no resistance at all and
further indentation
of the area being examined to great resistance or "guarding." This resistance
from the
patient in response to the applied force from the activated cells will be
detected by the
cell pressure transducer 244 or 444.
The mechanical resistance response detected by the activated pressure
transducer 244 or 444 of the PEM 200 or 400 is converted into an electrical
signal which
is transmitted back to the command control box 300 or the remote computer 260
at the
patient's location. As previously described for the input command set, this
analog
electrical signal will be processed 308 and converted to a digital signal 310.
This digital
signal is then transmitted back to the physician's computer 160 via the
communications
systems 312. As previously described for the HCU 100 output signal, the
software
program is responsible for receiving the incoming digital electrical signal(s)
from each
active area of the PEM 200, 400, assessing the corresponding magnitude of each
of the
PEM 200, 400 output pressures, and converting them into equivalent digital HCU
100
resistance signals. The digital signals are then converted to an equivalent
analog
electrical signal 132, post-processed 130, then directed to the appropriate
preselected
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piston resistors of the HCU 100. The output resistance produced by the piston
resistors 148 at the HCU 100 is equal to response pressure produced by the
patient in
response to the HCU 100 input pressure stimulus.
The counter-resistance provided by the piston resistor 148 will provide the
physician with a tactile simulation of the patient's response to pressure
applied over the
selected area of the patient's anatomy. The system is real-time and dynamic
such that the
physician may simulate press-release or press-partial release maneuvers on a
continuous
basis within the region of preselected cells. The three key components of the
device: the
physician hand control unit, the computer software, and the patient
examination module
provide a system for a continuous, real-time, action-reaction feedback loop.
It is the
differential resistance between the physician's applied pressure and the
patient's resistive
response perceived by the physician's hand against the hand control unit that
the
physician can then interpret and use for medical decision-making.
A flow chart showing the overall process that will be controlled by the
software in
the preferred embodiment is diagrammed in FIGURES IOA-IOC. The user, generally
the
physician, first logs into the system 500. A mechanism for logging in is
provided by any
conventional means, including for example a biometric scanner in the HCU
(i.e., a
fingerprint reader, not shown) or a more conventional requester for a user
identification
and password may be provided at the physician's computer 160. The software
then
queries for the system date and time 502, establishes a connection with the
PEM and
checks the status of the HCU and PEM 504, then establishes the necessary
communications links 506 therebetween. In the preferred embodiment, a first
database is
accessed 508 by the physician's computer 160 to obtain the various calibration
factors for
the HCU and PEM components, such as the pressure transducers and pressure
producing
devices (linear actuators). Various other initiation functions are then
performed by the
software 510, which functions may include establishing the sampling rates for
the
pressure transducers and initiating and calibrating the components (for
example, establish
the "zero pressure" level for the pressure transducers).
Patient identification and biometric information may then be input 512, both
to
verify the identity of the patent for the medical records and to establish
baseline
parameters that may be helpful to the examination, such as the general size
and age of the
patient. The physician then selects the anatomical location to be examined
514. In the
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preferred embodiment, a database of anatomical data is accessed 516, which may
include
generic still or animated pictures of the portion of the anatomy that is to be
examined. It
is contemplated that embodiments of the present invention may use the patient
medical
and biometric information, in addition to generic information relating to the
portion of the
anatomy that is to be examined, to adjust various system parameters, such as
the
sensitivity of the pressure transducers and linear actuators. The physician
then selects the
portions of the HCU that will provide output signals to the PEM 518, the
portions of the
HCU that will receive feedback pressures from the PEM 520, the cells of the
PEM that
will receive the pressure signals from the HCU 522, and the cells of the PEM
that will
send pressure signals back to the HCU 524. It is anticipated that in most
applications
there will be a one-to-one correspondence between the active HCU portions, and
the
activated PEM cells, for example, that the HCU sensory modulation subunits
will send
and receive pressure signals to and from the same PEM cells. However, the
ability to
disassociate the send and receive signals is believed to provide additional
functionality to
the system. The present invention contemplates systems wherein it is not
possible to
disassociate the HCU input and output pressure signals.
The software can also coordinate the position of the activated segments of the
HCU with the PEM 526, such that movement of the HCU, in a manner similar to
moving
a mouse, is tracked by the system to make a corresponding change in the PEM
cells that
are activated. Prior to the application of any force to the system,
predetermined force
alteration functions can be applied 528, such as force
amplification/magnification or
reduction/minimization of the HCU and PEM output signals. Forces are applied
to the
HCU 530 by the user, and the pressure signals generate low-amperage signals
532 in the
pressure transducers 144 (HCU-P1), that are sent to the signal processor to
produce
corresponding higher-amperage signals 534, and then converted to digital
signals 536
(D-HCU-P1). The D-HCU-P1 are used to generate digital pressure signals for the
PEM 538 (D-PEM-P1), and transmitted 540 from the physician's computer 160 to
the
remote computer 260. The D-PEM-P 1 pressure signal is then converted to a low
amperage analog signal (PEM-P1) 542, that is applied to the variable pressure
producing
device 248 of the PEM, and a corresponding force is applied to the patient
546.
The patient resistance response is detected by the selected PEM cell 548,
producing a pressure response signal (PEM-P2) 550, that is processed to
produce a higher
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amperage signal 552 and digitized (D-PEM-P2) 554. The D-PEM-P2 pressure signal
is
used to generate a corresponding digital pressure signal for the HCU 556,
transmitted
from the remote computer to the physician's computer 558, and converted to an
analog
signal 560 that is provided 562 to the appropriate HCU piston-type variable
resister 148
to produce a responsive force at the HCU. If the examination is complete 566,
then the
system will reset to allow the physician to begin another exam of a different
part of the
patient's anatomy. Otherwise the physician can apply additional forces and
detect
additional responses from the patient.
Although the process has been described in terms of the preferred embodiment,
it
will be obvious to one of ordinary skill in the art that variations on the
above process are
possible. For example, an embodiment may be possible wherein the pressure
signals
from the pressure transducers are usable, without pre-processing to a higher
amperage, or
pressure transducers may be used with integral A-D converters whereby a
digital signal is
produced directly. Optionally, the HCU and PEM may be connected directly to a
common computer or a specialized data processing system for applications where
the user
and the patient are in close proximity. The invention can clearly be practiced
without the
additional functionality provided by an anatomical database. Additionally, it
will be clear
to one of ordinary skill in the art how the process flow shown in FIGURES 10A-
10C
would be modified to accommodate the hydraulic or pneumatic embodiments of the
PEM
described above.
Additional Applications
While the original intent of the HCU 100 is to simulate a physical examination
of
a patient in a remote location, applications within the field of medicine
would include the
ability to examine a patient in hostile environments such as deep sea, space,
battlefield
conditions, remote locations, and/or mountain/jungle expeditions. The present
invention
may also be adapted for non-medical and/or recreational usages, where it is
desirable for
an individual to examine, feel, or otherwise elicit a tactile response from
another
individual, body or object in a remote location.
Portable versions could also be applied in a medical station within the
workplace,
obviating the necessity of a patient having to actually leave work and
traveling to a
physicians office. This is very inefficient for both the patient and the
physician.
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It is also contemplated that with the growing use of robotic tools for
performing
operations, that the above-described invention could be modified in a
straightforward
manner to provide a physician with tactile feedback while performing an
operation using
a robotic system.
Portable versions could also be applied in the home where some evaluations
could
preclude the need for after-hours trips to the emergency room. This efficiency
would
have a significant effect on overall health care costs.
Any application requiring tactile information or three-dimensional tactile
modeling of a physical structure required by an individual in a non-contiguous
location is
also within the scope of the present invention.
The present invention could also be adapted to enhance the ability of the
visually
impaired to communicate or feel objects without actual direct physical contact
between
the object and the blind individual.
While the preferred embodiment illustrated and described provides for external
examination of a patient, it should be understood that the PEM could be
alternately
configured for use within a body cavity or incision.
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