Abstract:
A visual stimulation cane or walking stick assists a Parkinson&#39;s Disease patient in overcoming a sudden immobility or freezing episode. The cane carries a visual indicator, which can be a plastic strip or leg, and which can be extended when needed to provide visual stimulation to initiate stepping. An actuator mechanism can include a plunger at the base of the cane, and a pivot member on which the indicator leg is carried. A lock/unlock knob allows the cane either to be used as a normal walking cane without visual stimulation, or to be used to overcome a freezing episode.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to walking assistance devices, such as canes, crutches, and walking sticks, and is more particularly directed to such a device that includes a visual stimulation mechanism to assist a Parkinson&#39;s Disease victim in overcoming a sudden loss of mobility or motor block episode, i.e., “freezing.” 
     Parkinson&#39;s Disease is a neurological disorder caused by imbalance of chemical messengers in the central nervous system. This disease can result in loss of control over voluntary movement in the patient. Some of the well known symptoms are resting tremor, i.e., shaking; slowness of movement or bradykinesia; muscular rigidity or stiffness; and impairment of postural righting reflexes, i.e., balance. Other symptoms may include changes in gait while walking, including shuffling of feet, short steps, difficulty with turns, and decreased arm swing on the affected side. The usual medical management strategy involves medication, and this often may lead to a satisfactory and productive quality of life. A regular exercise regimen will often be beneficial in reducing these symptoms somewhat, as the muscular and skeletal system are not directly affected by this disease, and exercise such as regular walking keeps the body healthy. However, walking can be affected by the sudden immobility or freezing. 
     Many people with Parkinson&#39;s Disease, or PD, periodically experience a motor block episode, often called “freezing”, in which the person is suddenly made immobile, with a feeling as if his or her feet are “glued” to the floor. This can happen suddenly while walking, and can lead to loss of balance and falls. The occurrence of freezing is controlled somewhat by the patient&#39;s medication, but will occur without warning in more advanced cases, or in less advanced cases where the medication wears off. Adjusting the PD medication will not always fully solve this problem. Freezing episodes are sometimes triggered by visual stimuli, such as a change in flooring patterns, or from observing an elevator door closing or opening. Freezing occurs rather frequently when the patient is navigating through narrow passageways or small spaces. Freezing episodes will usually resolve spontaneously, but this demands time and patience. Coping with this problem can be annoying and frustrating to the PD patient. Where this happens frequently, the patient is often afraid to go out or to engage in any sort of activity on foot. 
     Some compensating strategies that have been tries include visualization techniques, that is, imagining a line or object on the floor, and then stepping over the imaginary object. This strategy can be successful, but requires training and concentration. Other strategies include changing the visual focus to a distant point instead of looking directly below; counting a cadence or marching in place; or rocking from side to side to break the forward “freeze.” 
     Many PD patients carry a cane or walking stick simply to assist in balance during walking. This can also be of help if balance or strength on the affected side is affecting gait stability. However, this should usually be a straight cane or stick, as tripod or quad canes are difficult for a PD patient to use correctly. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Accordingly, it is an object of this invention to provide a simple device that will assist a PD patient to overcome the sudden immobility or “freezing” as discussed above. 
     It is another object to provide a cane or stick that can be used as a visual stimulation to break the freezing and help the patient to initiate the first step. or can be used as a 
     It is yet another object to provide a cane or stick that can be used by the PC patient as the necessary stimulation for walking, and may also be used as a walking cane to assist in balance. 
     It is a further object to provide a visual stimulation cane that is of straightforward design, is light weight, and does not have a great cost. 
     In accordance with an aspect of the present invention, a visual stimulation cane has a lightweight shaft having an upper end and a lower end. Favorably, there is a handle at the upper end, and a visual indicator at the lower end of the shaft. The visual indicator can be extended over the floor, ground, or other walking surface as a visible line or bar which the user can step over. Thus the visual stimulator helps the patient in overcoming a freezing episode. This visual indicator at the base of the cane can be extended, when needed, from a withdrawn position to its extended position. An actuator mechanism is situated at the lower end of the shaft permitting the user to move the visual indicator between its withdrawn and its extended positions. Preferably, the visual indicator is in the form of a thin semi-rigid strip or leg that can swing up to the withdrawn position along side the shaft of the cane, or can be swung down to a substantially horizontal position as a visual stimulus. In one preferred arrangement the cane has a spring-loaded piston or plunger that extends from the lower end of the shaft, and the leg is mounted on a pivot member that is rotated by the plunger. When downward pressure is applied on the handle, the leg comes down to its extended position and provides the necessary visual stimulus. The leg retracts back to the raised position when pressure is released. There can be a locking mechanism, i.e., a knob or other switch, to lock the visual indicator in the withdrawn or raised position, so that the cane can be used simply for balance. The shaft can be made as an upper and lower tube that telescope together and can be adjusted for the proper length. 
     In an alternative arrangement, a different visual indicator can be used. For example, the indicator may take the form of a coiled metal tape, like a steel measuring tape, that rotates and uncoils out to an extended position when the user presses down on the handle, and recoils back into the lower part of the cane when the downward pressure is relieved. In some circumstances, a laser or lamp could provide a line of light on the floor or walking surface as a visual stimulus. 
     The above and many other objects, features, and advantages of this invention will become apparent to persons skilled in the art from the ensuing description of a preferred embodiment, which is to be read in conjunction with the accompanying Drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of a visual stimulation cane according to one embodiment of the present invention. 
     FIG. 2 is an enlargement of a lower portion of this embodiment. 
     FIG. 3 is an exploded assembly view of this embodiment. 
     FIG. 4 is a cross sectional view showing details of this embodiment. 
     FIG. 5 is a cross sectional view showing the visual indicator leg in its lowered or extended position. 
     FIGS. 6 and 7 are perspective views demonstrating a Parkinson&#39;s Disease patient employing the cane of this embodiment to overcome a “freezing” episode. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the Drawing, and initially to FIGS. 1 and 2, a visual stimulation cane  10  is shown to include a tubular aluminum shaft  12  that is in two telescoping components, i.e., a lower or center tube  13  and an extendible upper tube  14 . An L-shaped handle  16  is fitted into the upper end of the upper tube  14 , and in this case has a grip  16  for comfort and security in gripping the cane. Of course, in other embodiments, there can be a J-shaped handle, T-shaped handle, a knob, or other handle configuration. 
     A visual stimulation assembly  18  is situated at the lower or distal end of the shaft  12 . In this case there is a plunger  19  that has a limited vertical travel and an indicator leg  20  that swings between a raised or withdrawn position, here shown in full line, and a lowered or extended position, here shown in ghost line. A pivot member  21  in the assembly  18  rotates when the plunger  19  travels, and carries one end of the indicator leg  20 . Here, the leg is an elongated flexible, thin plastic member, and is removably held a retainer on the pivot member, so that it can be replaced easily if broken. A supply of extra legs  20  can be stored within the cane, for example, in the handle  15 . The leg  20  can be colored a bright color on its upper side (i.e., considered in the extended position), for better visibility. A rubber tip or pad  22  can be situated at the base of the plunger  19 . 
     The assembly  18  has a housing  23 , formed of a front housing half  24  and a rear housing half  25 , which fits onto the lower end of the center tube  13 . A lock/unlock knob  26  can be rotated ninety degrees in one direction to permit the plunger  19  to move and rotate the pivot member  21  and leg  20 , and can be rotated ninety degrees in the other direction to block movement of the plunger  19  as well as the pivot member  21  and indicator leg  20 . In other arrangements, other locking mechanisms can be employed. In some versions, the locking knob may be on the handle. 
     The visual stimulation cane  10 , and in particular the assembly  18 , is shown in greater detail in FIGS. 3 and 4. As shown in FIG. 3, a snap lock button  27  is fitted within the shaft  12  and engages with holes  28  in the upper tube  14 . This permits the length of the cane  10  to be adjusted to the user&#39;s needs. In the visual stimulator assembly  18 , a coil spring  29  fits over a reduction or neck  30  on the upper part of the plunger  19 , and engages both a shoulder of the plunger  19  and an upper wall of the housing  23 . There is a generally key-hole shaped knob clearance passage  31  in this neck  30  through which the shaft of the knob  26  passes. The shaft has an oblong cross section, so that it engages the upper round part of the passage  31  when turned one way, but permits the lower straight portion to pass when the knob is turned in the other direction. 
     As shown in FIG. 4, a guide pin  32  is mounted on the plunger  19  to engage a radial slot  33  in the indicator pivot member  21 . The pivot member  21  is mounted by a pivot pin  34  to the indicator housing  23 . When the knob  26  is turned to the unlock position, and the user applies a downward pressure on the cane  10 , the pressure will move the plunger  19  upwards into the housing, and rotate the pivot member  21  and indicator  20  from the upward, or withdrawn position of FIG. 4 to the lowered or extended position of FIG.  5 . These two positions involve a rotation of between about 90 and 100 degrees, and in this embodiment, about 97 degrees. 
     Also shown in FIGS. 3,  4  and  5 , the front and rear housing halves  24 ,  25  are secured together by shoulder screws and lock washers, with the upper screw attaching to the center tube  13  and the lower two screws also guiding the travel of the vertical plunger  19 . In other versions, other fastening means could be employed. In this embodiment, the handle  15  is a separate member attached to the upper tube  14 , but in other versions, the handle could be formed by bending an upper portion of the tube  14 . 
     The use of this cane  10  is rather straightforward. 
     For ordinary conditions, the knob  26  can be placed in the locked position, and the cane can be used as a normal walking cane or walking stick to help the user keep his or her balance. The visual stimulation cane can be adjusted for height. The position of the indicator  20  relative to the handle  15  may be rotated, so that the cane can be used on either the left hand side or the right hand side, whichever is preferred. That is, the cane  10  can have the indicator leg  20  extend either to the right or to the left. In many patients, PD affects one side more than the other, and the cane  10  may accommodate that. The rubber tip or bumper  22  prevents slipping when the cane is used as a walking assistance and balance device, and also prevents slipping when downward pressure is applied to extend the indicator leg  20 . 
     When the user begins to experience a freezing episode, and is suddenly immobilized due to this effect of Parkinson&#39;s Disease, the user only has to release the locking mechanism by rotating the knob  26 . Then the user places the visual stimulation cane  10  a short distance in front and on the side of the dominant foot, as shown in FIG.  6 . The user applies a small downward pressure, for example, simply by leaning forward slightly. This pressure rotates the indicator pivot  21 , which moves the indicator downward to the extended position, which is now a short distance ahead of the user&#39;s foot. The indicator leg  20  creates a line on the floor or other walking surface, such as a footpath or lawn, and gives the user the visual stimulation necessary to initiate the first step. The user then steps over the extended indicator leg  20 , as shown in FIG.  7 . When the pressure on the handle  15  is released, the indicator leg  20  retracts. The user may repeat this process as many times as is necessary. 
     Use of this cane  10  permits the PD sufferer to enjoy much greater mobility by permitting him and her to deal easily with the possibility of sudden immobility. This reduces the fear of being unable to move, thereby encouraging and permitting the user to enjoy more normal work and recreation activities, and to lead a more enjoyable lifestyle. In some cases, this may permit the treating physician to reduce the dosage or frequency of PD medication. 
     While the invention has been described in detail with respect to one preferred embodiment, it should be recognized that there are many alternative embodiments that would become apparent to persons of skill in the art. Many modifications and variations are possible which would not depart from the scope and spirit of this invention, as defined in the appended claims.