Assistive devices

Assistive devices for mobility/ambulation can be referred to as ambulatory aids. Ambulatory aids (eg, canes, crutches, walkers) are used to provide an extension of the upper extremities to help transmit body weight and provide support for the patient. The type of ambulatory aid needed depends on how much balance and weight-bearing assistance is needed. Generally, the more disabled the individual is, the greater the complexity required in the walking device. A walker supplies the most support, and a standard cane provides the least.

Uses of assistive devices include the following:

• Redistribute and unload a weight-bearing lower limb • Improve balance • Reduce lower limb pain • Provide sensory feedback

Adequate upper limb strength, coordination, and hand function are required for the proper use of ambulatory aids.

Assistive devices for ADL, as well as for self-care and leisure activities, range from simple objects for daily use (eg, plate guards, spoons with built-up handles, elastic shoelaces, doorknobs with rubber levers) to complex electronic devices, such as voice-activated environmental control systems.

Batavia and Hammer identified 4 key evaluation and selection criteria for long-term users of assistive devices.

• Effectiveness - The extent to which the function of the device improves one's living situation, functional capability, or independence • Affordability - The extent to which the purchase, maintenance, or repair of the device causes financial difficulty • Operability - The extent to which the device is easy to operate and adequately responds to demands • Dependability - The extent to which the device operates with repeatable and predictable levels of accuracy under conditions of reasonable use

Assistive devices and their use for impairments Impairments and the associated assistive devices that aid in ambulation and mobility are as follows:

• Mildly impaired balance/stability - Single-point cane • Unilateral lower limb pain/mild weakness - Single-point cane; hold with unaffected side • Moderate impaired balance/stability - Quad cane (narrow or wide base) • Moderate-to-severe unilateral weakness/hemiplegia - Walk cane/hemiwalker • Bilateral lower extremity weakness/paralysis - Bilateral crutches or walker (pickup or front-wheeled) • Severely impaired stability - Walker (pickup or front-wheeled) • Impaired wrist or hand function - Platform forearm walker • Difficulty climbing stairs - Stair-climbing walker • Impaired bed mobility - Bed rails (half or full); hospital bed (manual or electrically controlled) • Difficulty with transfer - Transfer (sliding) board • Difficulty getting up from chair - Seat-lift chair or uplift seat assist

Impairments and the associated assistive devices that aid in ADL are as follows:

• Limited hand function and fine motor control

o Eating - Built-up utensils, universal cuff with utensil hold o Dressing - Button hook, zipper hook, Velcro closure, sock aid, long shoe horn, elastic shoe laces o Bathing - Wash mitts, long-handled sponge o Grooming - Built-up combs or brushes, electric toothbrush, electric razor with custom handle • Loss in 1 hand of eating-related functions - Plate guard, rocker knife • Impaired coordination, tremor - Weighted utensils • Impaired range of motion (ROM) of shoulder, proximal weakness - Reacher • Impaired mobility for toileting - Bedside or rolling commode, raised toilet seat, grab bars around toilet • Impaired mobility for bathing - Tub transfer bench, hand-held shower, grab bars on tub or shower; shower chair

Impairments and associated assistive devices to aid in communication are as follows:

• Difficulty holding pen to write - Built-up pen or pencil • Difficulty typing - Typing stick • Reading difficulty caused by impaired vision - Magnifying glasses, talking clock or watch • Difficulty dialing and using phone - Push-button dialing or 1-touch dialing with speaker phone; voice-activated phone • Difficulty calling for help - Simple buzzers or other signaling devices operated by switches that require minimal pressure; medical alert system, such as Life Alert.

Impairments due to complete loss of all 4 limbs or limb motor function:

• Brain-computer interface (BCI) devices or motor neuroprosthetic devices are systems that allow individuals to translate in real time the electrical activity of the brain into overt device control such that it reflects the user’s intentions. In essence, these constructs can decode the electrophysiologic signals representing motor intent. They do not rely on muscular activity and can therefore provide communication and control for those who are severely paralyzed due to injury or disease. • Current BCIs differ in how the neural activity of the brain is recorded, how subjects (human or animal) are trained to produce a specific electroencephalographic response, how the signals are translated into device commands, and which application is provided to the user. Patients with any of a variety of conditions, such as locked-in syndrome, spinal cord injury, stroke, limb loss, or a neuromuscular disorder, may benefit from the implantation of these BCIs, which augment the ability of a patient to communicate and interact with his/her environment.

Impaired vision and blindness:

• Good, older methods of providing sensory substitution for people with severe visual impairment include the use of visual-impairment canes and guide dogs. A more complex aid for the visually impaired, a human-machine interface utilizing an array of electrical stimulators on the tongue, has been developed; the technology was quantified using a standard ophthalmologic test. Using the interface, subjects achieved an average acuity of 20/860 without training; the figure doubled following 9 hours of training. The interface may lead to the development of practical devices for persons with sensory loss, including individuals who are blind Canes

Canes widen the base of support and decrease stress on the opposite lower extremity. Canes can unload the lower limb weight by bearing up to 25% of a patient's body weight.

Canes can be made of wood or aluminum; tubular aluminum is lighter than wood. Aluminum canes are adjustable, which is a characteristic that facilitates their use by patients of all sizes.

Determining the proper cane length is important. A cane that is fitted incorrectly produces an inefficient gait pattern. A short cane reduces support during the stance phase, and it tends to keep the elbow in complete extension. A long cane causes excess elbow flexion, which leads to increased muscle fatigue on the triceps and shoulder muscles. To determine the proper cane length, measure from the tip of the cane to the level of the greater trochanter while the patient is in an upright position. The elbow should be flexed approximately 20°.

Types of canes

Generally, the following 3 types of canes are used:

• C cane - This is the most commonly used cane. Other names used for this device include the crook-top cane, the J cane, and the single-point cane. • Functional-grip cane

o This type of cane provides better grip and more controlled balance for patients. o The grip of a functional-grip cane is more comfortable than that of a C cane. o The ortho cane is an example of a functional-grip cane. • Quad cane

o Quad canes provide more support than do other standard canes. o Narrow- and wide-based forms of quad canes are available. o Quad canes are especially helpful for patients with hemiplegia. o Slow gait is one disadvantage of quad canes.

Other types of canes include the following:

• Walk cane (hemiwalker)

o This type of cane combines the features of a walker and a quad cane. o Hemiwalkers usually are made of tubular aluminum, are adjustable, and can be folded. o Hemiwalkers provide a wider base and more lateral support than do the regular quad canes. o Indications for a hemiwalker include the following: . Patients with hemiplegia . Individuals who need an intermediate step during gait training; often used during the period after use of the parallel bars and before ambulation, which is a time when the patient needs less restrictive assistive devices • Visual impairment cane

o Features . Lightweight . Flexible . Easily collapsible o The distal inches of the cane are red. o To determine the proper length of the cane, measure the distance from the hand to the floor while the shoulder is flexed 90° anteriorly.

Biomechanics

The cane usually is used on the side opposite the affected lower limb. The cane helps decrease the force generated across the affected hip joint by decreasing the work of the gluteus medius-minimus complex. The force is exerted by the upper extremity through the cane to help minimize pelvic drop on the side opposite the weight-bearing lower limb. If the cane is held on the affected side, the affected hip in turn experiences an increased load of 4 times the body weight during ambulation.

Function

• Ambulation

o The cane usually is held on the patient's unaffected side so that it provides support to the opposite lower limb. o The cane is advanced simultaneously with the opposite, affected lower limb. o The weight is borne through the arm as needed. o The patient always should have the unaffected lower limb assume the first full weight-bearing step on level surfaces. • Stair climbing o The mnemonic "up with the good and down with the bad" can help patients to recall the appropriate step pattern for stair climbing. The cane is used for extra support when ascending/descending stairs. Often, the patient also has a rail to hold on the other side for added safety. o Advance the unaffected lower limb first when going upstairs, and advance the affected lower limb first when coming downstairs. o The patient always should have the unaffected lower limb assume the first full weight-bearing step on level surfaces.

Crutches

Crutches have 2 points of contact with the body, providing better stability than do canes. Two types of crutches (ie, axillary, nonaxillary) currently are in use.

Axillary crutches

An axillary crutch is a type of orthosis that provides support from the axilla to the floor. Wood and aluminum axillary crutches, both of which are adjustable, are available. An extension crutch (ie, one with an adjustable length) is heavier than a regular crutch because of the extra piece of wood. Standard axillary crutches have double uprights with a shoulder piece, as well as a handgrip or bar.

The primary advantage of an axillary crutch is that it allows transfer of 80% of the individual's body weight. Axillary crutches provide better trunk support than do nonaxillary or forearm crutches, and patients can free their hands for activities by leaning on the shoulder piece. However, the patient should be advised of the possibility of sustaining compressive brachial neuropathies with the use of axillary crutches. The axillary crutch is not designed to be rested on for body support. Patients should avoid resting their body weight on the axillary area. Providing extra padding to the axillary area should be discouraged for this reason.

The measurement prescription for axillary crutches is determined in the following manner:

• With the patient standing, determine the crutch length by measuring the distance from the anterior axillary fold to a point 6 inches lateral to the fifth toe. • With the proper crutch length determined and the crutch then placed 3 inches lateral to the foot, proper handpiece location can be measured. The patient's elbow should be flexed 30°, the wrist should be in maximal extension, and the fingers should be held in a fist. • The patient should be able to raise his/her body 1-2 inches by performing complete elbow extension.

Ortho crutch

• A single-bar aluminum crutch with a contoured underarm piece • Has an adjustable handpiece • Lighter than a regular crutch

Nonaxillary crutches

Nonaxillary crutches allow the transfer of 40-50% of the patient's body weight. Also called forearm or arm canes (or forearm or arm orthoses), these devices require good trunk control. The patient needs confidence in his/her ambulation skills.

Lofstrand crutches/Canadian crutches

• Most popular of nonaxillary crutches • Most useful substitute for canes • Most often used bilaterally • Made of tubular aluminum • Padded hand bar • Forearm cuff

o The open end of the cuff is placed on the lateral aspect of the forearm to permit elbow flexion and grasping without dropping the orthosis. o The proximal portion of the orthosis is angled at 20° to provide a comfortable, stable fit. • Measurement prescription - With the proper crutch length determined and the crutch then placed 3 inches lateral to the foot, the proper handpiece location can be measured. The patient's elbow should be flexed 20°, the wrist should be in maximal extension, and the fingers should be held in a fist. • Advantages associated with Lofstrand crutches include the following: o Ambulation is safer and easier. o This type of crutch is a good substitution for the cane, because the forearm support stabilizes the wrist during weight bearing. o The patient's hands are free to perform various tasks while the individual's body weight is supported through the forearm by the forearm cuff pivots. The patient does not have to worry about dropping the crutches. o These crutches are shorter than axillary crutches. • The disadvantage of Lofstrand crutches is that they provide less support for ambulation than do axillary crutches.

Wooden forearm orthosis

• The wooden forearm orthosis, also known as the Kenney stick (named after Sister Kenney), resembles the axillary crutch but ends proximally, with a leather band situated around the proximal portion of the forearm. • Indications for this orthosis include the following:

o Originally developed for patients with poliomyelitis o For patients who have good proximal upper limb strength but weak distal strength and who are unable to hold and control the orthosis effectively • An advantage to this type of crutch is that use of the closed leather band will prevent the patient from dropping the orthosis. (This is even truer than it is with the Lofstrand forearm orthosis.)

Platform forearm orthosis

• A platform is placed on the top level of the crutch. • A vertical handgrip is placed at the distal end of the platform. • Velcro straps are applied around the forearm. • This orthosis is very helpful for patients with a weak handgrip • The measurement prescription is arrived at by having the patient stand upright, with his/her elbow flexed 90°; the proper length for the orthosis is determined by measuring from the patient's resting forearm to the ground. • An advantage to this orthosis is that the patient's body weight is borne mostly by the forearm instead of by the hand. • Indications for the platform forearm orthosis include the following:

o Painful wrist and hand conditions (eg, arthritis) o Weak handgrip because of pain and deformities of the hands and wrists o Elbow contractures

Triceps weakness orthosis

• Other names for this device include the following:

o Triceps weakness crutch o Warm Springs crutch or Everett crutch (a metal version) o Canadian crutch (a wooden version) • The triceps weakness orthosis resembles the axillary crutch but ends proximally at the midarm level. • Two cuffs, one above and one below the elbow, support the elbow in extension. • The triceps weakness orthosis was originally developed for patients with poliomyelitis; it is used by patients who need help preventing the elbow from buckling during gait.

Other crutch components

• Crutch tips - Crutches without rubber tips or with inadequate rubber tips are dangerous. o Made of rubber and attached to the foot of the crutch o Should be at least 1.5 inches in diameter o Can have a retractable, metal-spiked tip for use on ice, enhancing patient safety by preventing slippage; absorbs shock but may be uncomfortable for the patient • Handgrips

o Made of sponge rubber o Can be built up or contoured according to the needs of the patient o Reduce pressure on the hands o Enhance safety (prevent slippage) • Axillary pads

o Made of sponge rubber o Prevent unnecessary pressure under the axillary region • Triceps band

o Made of metal or stiff leather and is attached to the upper part of the crutch o Assists the patient in maintaining elbow extension during weight bearing o Very helpful for patients with weak triceps • Wrist strap

o Made of either leather or plastic o Assists patients in making their handgrip o Very helpful for patients with weak wrist extensors

Crutch gaits

Crutch gaits used for specific indications

Gait training and preambulation exercises

At a minimum, gait training should include the following:

• Aerobic conditioning exercises • Coordination and balancing exercises • ROM of both upper and lower limbs • Muscle strengthening of both upper and lower limbs

Performing upper limb strengthening exercises is one of the most important components of the preambulatory exercise program.

Important muscle groups targeted include the following:

• Shoulder depressors • Latissimus dorsi • Lower trapezius • Pectoralis minor • Shoulder flexors • Elbow and wrist extensors • Finger flexors • Trunk (deep back) muscles - To help improve balance and endurance

The suggested training sequence begins with muscle strengthening exercises while the patient is nonambulatory. Once the patient can stand, begin balancing exercises with support (eg, parallel bars). Progress to having the patient perform balancing exercises with appropriate ambulatory aids. Once the patient's balance and posture are satisfactory, progress to ambulation with the most appropriate ambulatory aids. Advise the patient to continue practicing until ambulation with assistive devices has come as close as possible to the normal gait. Walkers

Advantages and disadvantages are associated with the use of a walker and should be considered when prescribing a walker as an assistive device for any patient.

• Advantage - Maximum support for the patient • Disadvantages

o Slow and awkward gait o Creates bad posture and walking habits o Limited to indoor use in most cases o Cannot be safely used to climb stairs (especially the standard walker) • Indications

o Best suited for patients who are confused or who have an unsafe gait because of poor balance (eg, patients with hemiplegia, patients with ataxia) o Early gait training • Measuring prescription

o Place the front of the walker 12 inches in front of the patient. The walker should partially surround the patient. o Measure the proper height of the walker by having the patient stand upright with his/her elbows flexed 20°. • Components

o Tubular aluminum or other tubular metal o Plastic handgrips o Rubber-tipped legs

Types of walkers

Standard walker (pickup walker)

• Most walkers are lightweight and very durable. • Standard walkers have adjustable legs, accommodating a large percentage of patients. • To use the standard walker for ambulation, the patient must have the upper extremity strength necessary to lift the device and place it forward.

Rolling walker (front-wheeled walker) • The rolling walker has wheels on the front legs; these wheels promote the walker's movement. • The rolling walker does not require as much strength and balance to maneuver as the standard walker does, because the patient does not have to lift it from the floor. • Rolling walkers are used by patients who, because of poor coordination of the upper extremity and trunk, are unable to lift the walker and move it forward. • Disadvantages

o The front wheels may create instability if they are not used properly. o Proper supervised training session is required to ensure patient safety.

Reciprocal walker

• This device has swivel joints that permit reciprocal action, with each side of the walker moving in alternation with the other. • An advantage of the reciprocal walker is that it allows a quicker and less awkward gait.

Forearm support walker

• Indications

o Patients with forearm deformities (wrists or hands) or pain o Patients with elbow flexion contracture • Disadvantage - Heavy

Stair-climbing walker

• This device requires good balance and great strength of the upper extremities. • The stair-climbing walker is prescribed for young patients with paraplegia. • A U-shaped extension is a possible additional component. This extension provides extra support in order to enhance stability for stair climbing.

Heavy-wheeled walker with foldaway seat and removable back

• Indication - Indoor institutional use • Disadvantage - Heavy, awkward, and unsafe

Four-Point Gait Three-Point Two-Point Gait Swing-through Gait Swing-to Gait Drag-to (Tripod) Gait (Non – Weight- Bearing) Gait Appropriate 1. Left crutch 1. Both crutches 1. Left crutch and 1. Both crutches 1. Both crutches 1. Left crutch Sequence 2. Right foot and the weaker right foot 2. Move both lower 2. Move both 2. Right crutch 3. Right crutch lower limb 2. Right crutch limbs past the limbs almost to 3. Drag both lower limbs to the 4. Left foot 2. The stronger and left foot crutches the crutches. crutches or (simultaneous or unaffected sequence) limb 1. Both crutches 2. Drag both lower limbs to the crutches Advantages Stability (at least 3 Eliminates Stability Fastest gait (faster Easy to learn Stability points are always weight-bearing than normal walking in contact with the on the affected Faster than the 4- gait) Lower energy ground) lower limb point gait consumption

Reduces weight- bearing on both lower limbs Disadvantages Difficult to learn Requires good Patient must expend a Patient must expend a large and/or balance and large amount of amount of energy Requirements Relatively slow coordination energy walking gait Slow Difficult to learn

Strong, functional abdominal and upper limb muscles and good trunk balance are required. Indications Weakness in the Lower limb Weakness in the Paraplegia, with strong Paraplegia Initial gait pattern used during gait lower limbs or poor fracture, lower limbs or upper body muscles training for patients with coordination amputation, or poor coordination paraplegia; once they improve their (ataxic) pain (ataxic) balance, patients can advance to the swing gait Appropriate 1. Left crutch 1. Both crutches 1. Left crutch and 1. Both crutches 1. Both crutches 1. Left crutch Sequence 2. Right foot and the weaker right foot 2. Move both lower 2. Move both 2. Right crutch 3. Right crutch lower limb 2. Right crutch limbs past the limbs almost to 3. Drag both lower limbs to the 4. Left foot 2. The stronger and left foot crutches the crutches. crutches or (simultaneous or unaffected sequence) limb 1. Both crutches 2. Drag both lower limbs to the crutches Advantages Stability (at least 3 Eliminates Stability Fastest gait (faster Easy to learn Stability points are always weight-bearing than normal walking in contact with the on the affected Faster than the 4- gait) Lower energy ground) lower limb point gait consumption

Reduces weight- bearing on both