From, ‘Caring for Persons with Huntington’s Disease’
Editor: Edmond Chiu, AM
Chapter 5, Physiotherapy
Elizabeth Barraclough, Janet Hodge, Jill Groom, Anne Hoy
Huntington’s Disease runs progressive inexorable course, and physiotherapy is unable to affect this. However, through a programme of general and specific exercises, the effects of muscle disuse and physical inactivity which compound the other physical and emotional problems of HD may be reduced. By minimising muscle atrophy and weakness and deterioration of body fitness it is possible to improve the HD person’s quality of life.
CLINICAL FEATURES APPARENT IN HUNTINGTON’S DISEASE AND RELEVANT TO PHYSIOTHERAPY TREATMENT
1) Disturbed neuromuscular Function
Usually within normal limits, although in those people in the later stages where rigidity is the predominant feature, mobility can be reduced but contractures are rare.
A decrease in muscle strength is evident and often asymmetrical. The postural muscle groups are primarily affected – neck and trunk extensors, scapular retractors, shoulder elevators, dorsiflexors, hamstrings and most noticeably, hip abductors and extensors.
Changes in Normal Posture:
Usually in the early stage postural abnormality is only slight, but there may be early signs of one or a combination of the following:
A wide base
Feet externally rotated – often one more than the other
Uneven weight bearing
Head held to one side and / or rotated
Later the arms assume bizarre positions – perhaps related to balance problems
Hyper-extension of hips – resting back on ligaments
There is great variation in gait pattern, e.g.
Lack of rotation
Lack of arm swing
Uneven weight bearing resulting in a list to one side, making it difficult to ‘step through’.
There may be flexion at the hips causing weight to fall forwards and resulting in an increase in momentum and often loss of control.
Sometimes ther is hyperextension at hips with a resulting danger of falling backwards. This hip extension may cause a more swaying gait.
Later there is difficulty with initiating walking.
The classical ‘dancing’ ataxic gait is also seen.
However, the early stage patient can walk and crawl in all directions, negotiate steps and transfer independently, but deterioration in normal timing and fluency of movement is evident. This is particularly noticeable in sideways and backwards movement.
From the early stage there is evidence of diminished control when transferring (e.g., from a standing position to a chair to a standing position).
As the disease progresses this can be further aggravated by an inability to judge distances accurately. Some have problems standing still.
There is evidence of deterioration of fluency and accuracy of voluntary movements. In asking a patient to perform the finger-nose test, the finger does not travel straight to the nose, but may curve or be broken by corrections. Instead of smoothly increasing at the onset and decreasing at the end, the movement may be excessive or unduly slow. Even in the early stage of the disease, rapid alternating movements (e.g. pronation, supination) may be difficult.
Movements in the early stages tend to be of small amplitude andddd promarilyaffect the distal parts of the extremities and, to a degree affect the facial muscles. As the disease progresses, the movements increase in amplitude and may affect neck, shoulder and pelvic girdles. Dyskinesia increases with stress, excitement and fatigue. It also increases as the size of the base of support decreases.
In the early stages, tested by passive joint movements, tone is within normal limits. But as the disease progresses there may be changes which could be hypotonic, hypertonic (rigidity) or variable (fluctuating).
There is deterioration in equilibrium reactions in the early stage when the base of support is narrow (e.g., standing) but later it is evident even when the base is wide – sitting or four-point kneeling.
Automatic Movement Reactions
Protective extension may be delayed or absent.
Mid Brain Reflexes
Righting reactions are depressed, and particularly noticeable is loss of rotation in gait and segmental break-up in rolling.
Lower Brain Stem Reflexes
Early stage patients may display subtle indications of tonic neck reflex activity, usually in the form of the Asymmetrical Tonic Neck Reflex (ATNR). The presence of the ATNR is usually associated with problems such as decreased trunk rotation and a decreasing ability to perform tasks which require a bilateral approach.
As deterioration occurs ATNR may become more pronounced. There may also emerge a Symmetrical Tonic Neck Reflex – extension of the head beyond vertical may produce a strong generalised extensor spasm whilst a flexion in front of vertical produces a generalised flexion pattern.
Associated reactions are often evident fairly early and become stronger as the disease progresses. These reaction may be evident even when there are no other signs of tonic reflex activity.