Device for Ameliorating Symptoms of gait-impaired patient
This invention relates to methods and apparatus for use in the treatment and amelioration of a gait-impaired patient, and in particular patients suffering from Parkinson's Disease.
Parkinson's Disease affects one in 500 of the population. At some point during the development of the disease, patients are in general affected by akinetic syndrome. Akinetic syndrome manifests itself by the sufferer losing their normal gait, taking abnormal steps and shuffling uncertainly, and at times stopping altogether. It has been known for many years that the gait of Parkinson patients can be improved, if lines are provided on the floor. For example, it is found that Parkinson patients can often walk reasonably well along a pavement with lines created by paving stones. Where the walking surface is smooth with no regular lines however, walking is found to be much more difficult. Other neurological diseases and trauma injuries, including some types of stroke, may also cause these Parkinson's-like symptoms.
Various attempts have been made to simulate the effects of gridlines on the walking surface by projection methods. For Example, US patent 5597309 discloses a method in which a head-up display is used to provide cues to the subject's field of vision, without obscuring the real world. This reference also discloses light emitting diodes fastened to eye glasses, to deliver virtual cues to the subject's field of view. Such methods however rely on scrolling of the visual cues within the subject's field of view, and on the presence in the field of view of at least two visual cues, with an intercue distance.
A number of publications describe the use of devices to provide light stimulation to the eyes, for the treatment of various mental disorders, and to assist with relaxation. For example, GB-A-2352182 describes the fitting of LEDs to goggles or glasses to stimulate the brain in the so-called beta frequency range (15-20 Hz). A similar device is described in US-A-5092669. Photic stimulators are also described in US-A-5709645, DE-A-3939401 and US-A-5306228. AU these devices rely on stimulation at the relatively high frequencies in the beta range (15-20 Hz) or the theta or alpha range (4-13 Hz), and do not have any relevance to the amelioration of the symptoms of Parkinson's disease. WO-A-2005/020866 and US-A-2005/0074729 describe devices for amelioration of Parkinson's disease, but relate to complex devices
involving either the use of a special walking surface, or of a sensor mounted on the body, and means for generating an image adapted according to body movements detected. No simple and inexpensive device has been proposed for ameliorating the symptoms of Parkinson's disease, during the normal ambulatory movement of a patient.
In accordance with the present invention, it has been discovered that, contrary to what was previously believed, significant improvements in gait of Parkinson patients can be achieved by the provision of a single visual cue, which is fixed in the patient's field of vision, and which alternates between the left and right eyes of the patient, particularly, at a rate which matches the patient's gait.
In accordance with a first aspect of the invention, there is provided a device for improving the gait of a gait- impaired patient, comprising: - a support frame adapted to be carried on the head of the patient, first and second cue means mounted on the device, for projecting a respective first and second visual cue at a respective fixed point in the field of vision of the left eye and the right eye respectively of the patient, and means for causing alternate actuation of the said first and second cue means, to activate the said first and second visual cues alternately. The alternate actuation is preferably provided at a rate which matches the patient's gait. The first and second cue means may be, for example, one or more light sources, for example light-emitting diodes (LED), or devices for causing a contrast change in an optical medium, for example a liquid crystal device. In a preferred embodiment, the first and second cue means are LEDs. The cue means are preferably mounted on the frame of the device, and in particular may be arranged along an edge of a screen or lens, mounted in the patient's line of vision and adapted to illuminate a chamfered edge of the screen or lens, so as to provide the said visual cue. In a particularly preferred embodiment, the light sources may be LEDs housed within an upper horizontal support bar of a support frame, for example, a spectacle frame, with the chamfered edge formed on the lower edge of the transparent screen or lens. In a preferred embodiment, the device may be incorporated within a conventional pair of vision correcting spectacles.
The visual cue is preferably positioned so that the patient sees his or her foot move through the visual cue line within their field of vision. Accordingly, the device preferably includes means for adjusting the position of each said visual cue within the field of vision of the patient, in order to obtain the optimum positioning thereof. In a presently preferred embodiment, the cue image is a horizontal line across the entire field of vision of each eye. In an alternative embodiment however, the cue image may be a shorter line or even a dot. Where the cue image is sufficiently small, a light source for example the end of a fibre optic fibre or fibre optic bundle may be placed directly in the field of vision. The cue images may be monochrome images, or multi-coloured images, so as to provide contrast appropriate for different backgrounds.
The cue means associated with the left and right eye of patient are activated alternately, at a rate which matches the gait of the patient. Accordingly, means are preferably provided within the device for varying the rate of alternation (i.e., the rate of illumination of the light sources), in order to adjust the device to match the patient's gait.
The support frame may be the frame of a pair of ordinary spectacles, having a pair of vision-correcting lenses, with the cue means appropriately positioned so as to project the desired visual cues into the field of vision of the patient. Alternatively, the support frame may resemble the frame of a pair of safety spectacles or goggles, with no vision-correcting lenses. In this case, a transparent screen may be provided through which the light sources can project the visual cues. In either of the above cases, the frame will generally include a headband or legs for location over the ears of the user, in order to position the frame on the user's head. In an alternative embodiment, the support frame may be adapted to be affixed (for example by means of a clip) to an existing pair of spectacles or goggles.
The device may include a control circuitry for actuating the cue means (typically, illuminating the light sources) in a number of different modes, in addition to the principal operating mode in which the light sources are illuminated alternately. In particular, during the adjustment phase, it is desirable to illuminate both light sources simultaneously and continuously, in order to facilitate positional adjustment of the
device. In an alternative mode, each light source can be activated separately and continuously, for the same purpose.
It has also been discovered, in accordance with an alternative embodiment of the invention, that some patient symptoms, for example the tendency of patients suffering from Parkinsons to fall over, can also be improved by providing a visual cue means (for example a light source such as an LED), positioned so as to provide a stimulus to the peripheral vision of the patient, and preferably activated on a random (including pseudo-random) basis. A peripheral vision cue means of this kind may preferably (though not necessarily) be employed together with the embodiments previously described.
Accordingly, in a further aspect of the invention there is provided a device for improving the balance of a patient, comprising a support frame adapted to be carried on the head of the patient, a visual cue means mounted on the device, and adapted to provide a visual cue within the peripheral vision field of the patient, and means for causing the random activation of the visual cue means.
The peripheral visual cue means may be an LED mounted on a side bar or side panel of the support frame, and positioned so as to direct light into the peripheral vision area of the patient. It has been discovered that the provision of such an additional light source, particularly if randomly activated, can be effective in further improving the gait of the patient. The precise reason for such improvement is not fully understood.
Preferred embodiments of the invention will now be described, with reference to the accompanying drawings, in which:-
Figure 1 is a schematic diagram of a device in accordance with the invention, in side view; Figures 2A and 2B are schematic front views of the device according to Figure 1;
Figure 3 is a side view of a device in accordance with Figures 1 and 2, incorporating an additional LED in the peripheral vision region;
Figure 4 is a front view of a device having a support frame which is adapted to be affixed to a pair of spectacles or goggles; Figure 4A is a side view of the device of Figure 4;
Figure 5 is a front view of the device of Figure 4 attached to a pair of spectacles;
Figure 5A is a side view of the device of Figure 4 attached to a pair of spectacles;
Figure 5B is a side view of the device of Figure 4 attached to a pair of spectacles showing alternative positioning of the device, such that the cue device is in contact with the spectacle frame; Figure 6 shows a plan view of the light guide and cue bar of the device of Figure 4; Figure 7 shows alternative embodiments for the shape of the cue bar; Figure 8 shows an end view of the light guide and cue bar of the device of Figure 4;
Figure 9 is a front view of an alternative device having a support frame which is adapted to be affixed to a pair of spectacles or goggles; Figure 9 A is a side view of the device of Figure 9;
Figure 10 is a front view of the device of Figure 9 attached to a pair of spectacles; Figure 1OA is a side view of the device of Figure 9 attached to a pair of spectacles;
Figure 1OB is a side view of the device of Figure 9 attached to a pair of spectacles showing alternative positioning of the device, such that the cue device is in contact with the spectacle frame;
Figure 11 shows a plan view of the light guide and cue bar of the device of Figure 4;
Figure 12 shows the shape of the cue bar in the device of Figure 4;
Figure 13 shows an end view of the light guide and cue bar of the device of Figure 4;
Figures 14 and 15 are plan and elevations respectively of a possible power supply location
Figure 16 is a schematic front view of the device according to Figure 1 incorporating a cue bar height adjusting device
Figure 16 A is a side view of the device of Figure 16 Figure 16B is a plan view of the device of Figure 16 Figure 16C is a magnified view of the nose bridge region of the device of Figure 16
Figure 17 is a front view of an alternative device having a support frame incorporating a cue bar height adjusting device which is adapted to be fixed to a pair of spectacles or goggles;
Figure 17A is a side view of the device of Figure 17 showing the adjusting mechanism
Figure 17B is a magnified front view of the cue bar height adjusting device
Figure 18 is a front view of an alternative device having a support frame which is adapted to be affixed to a pair of spectacles or goggles using a optic fibre bundle as a light guide;
Figure 18 A is a side view of the device of Figure 18
Figure 19 is a front view of an alternative device having a support frame which is adapted to be fixed to a pair of spectacles or goggles using a optic fibre bundle as a light guide;
The device of Figures 1, 2 A, 2B, and 3 comprises a frame (1), which supports a transparent screen (10) of a transparent material, for example toughened glass or polycarbonate. LEDs (2, 3, 4, and 5) are mounted in recesses in the upper edge (8) of the transparent screen (10). In normal use, upper edge (8) of screen (10) is housed within upper horizontal support bar (9) of the support frame (1). The frame (1, 9) is not shown in Figures 1, 2 A and 2B, to enable the positioning of the LEDs to be clearly seen. A recess (18) is provided, to support the device on the nose of the user, and legs (19) locate the device over the ears as with conventional safety spectacles.
Lower edges (6 and 7) of screen (10) are chamfered, whereby when the LEDs (2, 3, 4, and 5) are illuminated, the user sees an image 15 or "cue bar" projected on the floor (16).
Electronic circuitry (not shown) is provided so as to illuminate LEDs (2, 3, 4, and 5) in a desired sequence. LEDs (2 and 3) operate together to provide a cue bar (15) for the right eye, and LEDs (4 and 5) operate simultaneously so as to provide a cue bar (15) for the left eye. The electronic circuitry is a generally conventional form, and will not be described in detail. The circuitry is arranged so as to illuminate LEDs (2 and 3), then (4 and 5) alternately, at a rate which is matched to the gait of the patient. Figure 2 A shows LEDs (2 and 3) illuminated, thus providing a cue bar at chamfered edge (6). This provides a cue for the right foot to cross in the field of vision. In Figure 2B, LEDs (2 and 3) are switched off, and LEDs (4 and 5) are illuminated so as to provide a cue bar generated by chamfered edge (7), in order to cue the right foot.
The chamfered edge at (6 and 7) are polished to provide a mirror finish, and the height of the screen (10) can be adjusted in frame (1), so as to adjust the apparent position of the cue bar on the floor in front of the user.
As shown in Figure 3, an additional LED (21) is provided on a side-frame (22). LED (21) is positioned so as to be located in the user's peripheral vision area, and is connected to drive circuitry causing it to be illuminated at random time intervals.
With the arrangement illustrated, the chamfered edges (6 and 7) are virtually invisible when the LEDs are not illuminated, and therefore provide no visual distraction when the system is not activated. Similarly the additional LED (21) does not distract the normal vision of the user, but nevertheless has been found to improve walking ability.
Figures 4 to 19 show alternative embodiments adapted to be affixed to a pair of spectacles or goggles. Referring first to Figure 4, the device (100) has a support frame (101). The support frame (101) can be attached to the spectacles or goggles using a pair of clips (103, 105), wherein the clips attach to the spectacles or goggles on either side of the recess for the nose of the spectacles or goggles in a manner similar to that used in clip-on sunglasses.
The support frame (101) comprises a central bridging portion (107) designed to fit above the bridge of the nose and two arms (109, 110), each of which is positioned such that when the device is attached to a pair of spectacles (112), as shown in Figure 5A, the arms pass along either side of the recess for the nose, and then curve away from the nose recess so that they lie roughly horizontal and near to the lower edge of the spectacles. Each arm (109, 110) has a light source (115), positioned adjacent the central bridging portion (107), a cue bar (120) in the horizontal portion of the arm (109, 110), a light guide (118) for directing light from the light source to the cue bar (120), and an end (123) at the distal end of the arm, which is a silvered for internal reflection of the light.
The light source (115) is connected to control electronics (not shown) housed in a central housing (125) which is connected to the central bridging portion (107). As shown in Figures 14 and 15, a power supply in the form of a cell (160) for the control electronics may be may be housed in an expandable or slip-on plastic cover or sleeve (161) that fits over an arm of the spectacles and behind the ear of the wearer. In an
alternative embodiment (not shown) a power supply may be positioned in a central housing.
The cue bar (120) has a flattened surface (127) on the side facing the wearer in use and a curved mirrored surface. The silvered end (123) is angled. In use, light from the light source travels down the light guide to the silvered end. The angled nature of the distal silvered end (123) reflects the light onto the curved mirrored surface, and from there, light is emitted through the flattened surface (127), thereby providing a cue line image to the wearer. Suitable shapes for the silvered end (123) are shown in Figure 7. An alternative embodiment of a device for attaching to a pair of spectacles or goggles is shown in Figures 9 to 1OB. In this embodiment, the arms (109, 110) comprise a supporting arm (130), a cue bar (120) and the light source (133) is positioned within the cue bar. Alternative arrangements for the shape of the cue bar are shown in Figures 11 to 13, the same numbers being used to denote the same parts. Again a light source (133) is positioned within cue bar (120). The end portion (127) of the cue bar is shaped so as to provide a desired form of visible cue in the field of vision.
In use, the light source produces light which is reflected out of the cue bar to produce a cue line image to the wearer. In the embodiments of Figures 4 to 13, alternating cue line images are produced in the same manner as the embodiment disclosed in Figures 1 to 3.
In a particularly preferred embodiment, the support frame (101) is provided with means for adjusting the cue bar vertically relative to the position of the spectacles, as will be further illustrated in Figures 16, 16A, and 16B, and 17, 17A, and 17B.
A preferred arrangement for allowing such vertical height adjustment is shown in figures 16, 16A, 16B and 16C.
The device shown in 16, 16A, 16B and 16C corresponds in essential respects to the device of Figures 1 and 2, with the addition of an adjustable nose-spanning piece (202) capable of vertical adjustment by means of a simple screw jack method. Piece (202) is moulded or glued to a height- adjusting screw (200), which is received in a threaded block (203) fixed to the screen (10).
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An alternative arrangement for allowing vertical height adjustment is shown in Figures 17, 17A, 17B and 17C. In this embodiment, the arrangement is generally similar to that of Figures 5, 5 A and 5B, with the addition of height adjustment screws (207) and (208), which are journalled for rotation in block (206) attached to the clip- on retaining mechanism. The lower ends of screws (207) and (208) are threadedly received in member (204), affixed to the cue bar supporting device.
An alternative arrangement for illuminating the cue bar is shown in Figures 18, 18A and 19. In this arrangement, illumination is provided by a bundle of optical fibres passing through arms (109, 110). The distal ends of the optical fibres terminate at different locations (209, 210), along the cue bar. The proximal ends of the optical fibres are positioned adjacent LEDs 115, so as to permit light from LEDs (115) to pass into the optical fibre bundles
The simulated cue line image must be positioned so that the wearer's foot can pass through it, in order to provide the correct stimulus to aid walking. In order to achieve the correct positioning, account should be taken of the normal stride length of the user (typically 61 to 66cm in women, and 76cm in men), as well as the height, limb length, and degree of stoop of the patient. The adjustment can be accomplished by raising or lowering the cue bar.
In order to determine the correct adjustment, the patient is asked to stand on a black mat with their toes touching a reference line. A thin baton (painted white) is placed on the mat in front of them, and they are then asked to take a normal step towards this baton. The distance between the toe and reference line is recorded, and repeated a few times to show consistency. The baton is then placed at this distance minus 9cm (the approximate toe-to-ball measurement of the foot) from the reference line, which allows the patient to walk across the line.
The patient is again asked to stand with their feet touching the reference line, and look normally at the baton. With the control unit switched to control mode, in which all LEDs are continuously illuminated, the cue line is then adjusted so as to appear superimposed upon the baton. The control unit may be powered by a single conventional battery source, with the electronics housed in the frame of the unit. Alternatively, a connector may be utilised to provide a separate control unit which the user may carry in a pocket. Figures 14
and 15 are respectively plan and elevation views of an arrangement suitable for locating a battery, in the arrangement shown the the other Figures.
Adjustment may be provided to enable the user to take account of ranges of ambient lighting conditions. . In a preferred embodiment, the device may incorporate means for measuring the walking speed of the user (a pedometer), which may be of generally conventional form, and switching circuitry to activate the cue bars in synchronisation with the walking speed of the user, in dependence upon a signal received from the pedometer.
In a particularly preferred embodiment, the device may incorporate a movement, attitude, direction sensing and control device to initiate walking, balance, or other function / correction etc which may or may not be used in conjunction with the arrangement described above.
Such means for sensing the attitude of the user may incorporate a gyroscope and means for initiating operation of various functions of the device depending on the movement pattern sensed. For example, change of vertical attitude in a forward-to-backward direction may indicate the initiation of ambulation, and be used to trigger the appearance of cue lines in the field of vision. Change of vertical attitude in a side-to-side direction may indicate a tendency of the patient to fall sideways, and therefore be used to trigger LEDs (21) positioned in the user's peripheral vision area, to correct the tendency to fall.
Although the invention has been described with reference to the particular preferred embodiment shown in the drawings, it will be appreciated that many other variations are possible, within the scope of the appended claims.