Abnormal Movements

Published on 09/04/2015 by admin

Last modified 09/04/2015

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Abnormal Movements

BACKGROUND

Abnormal movements are best appreciated by seeing affected patients. If you are armed with the right vocabulary, most common abnormal movements can be described. However, many experts will describe the same movements in different ways—so journals about movement disorders come with video clips to illustrate the movements!

In most patients with movement disorder, the diagnosis depends on an accurate description of the clinical phenomenon.

There is frequently a considerable overlap between syndromes, and several types of abnormal movement are often seen in the same patient—for example, tremor and dystonia in a parkinsonian patient on treatment.

The anatomy of the basal ganglia is complicated and wiring diagrams illustrating the connections between the various structures become more complicated as more research is done. Neuro-anatomical correlations are of limited clinical value as most movement disorders are classified as syndromes rather than on anatomical grounds. Correlations of significance include unilateral parkinsonism due to lesions of contralateral substantia nigra and unilateral hemiballismus due to lesions of the contralateral subthalamic nucleus or its connections.

In evaluating movement disorders, there are three aspects to the examination:

1. Positive phenomena

– the abnormal positions maintained

– the additional movements seen.

2. Latent phenomena

– the abnormal phenomena that can be revealed using various manœuvres (e.g. rigidity on testing tone and the abnormal postures brought on by writing in writer’s cramp).

3. Negative phenomena

– the inability to do things: for example, a slowness in initiating actions (bradykinesia).

Terms used in movement disorders (Fig. 24.1)

Akathisia: motor restlessness where the patient constantly shifts, crossing and uncrossing his legs and walking on the spot.

Athetosis: slower, writhing, irregular movements predominantly in the hands and wrist (used less frequently now).

Chorea: non-rhythmical movements of a rapid, jerky nature which frequently appear pseudo-purposeful. They may be voluntarily controlled for a short time.

Dyskinesia: a term used to describe movements associated with neuroleptic drugs; particularly used to describe movements of mouth and face (orofacial dyskinesia).

Dystonia: co-contraction of agonist and antagonist which may lead to an intermittent or persistent maintenance of abnormal posture. Position maintained is usually at an extreme of extension or flexion.

Hemiballismus: violent and flinging movements which are irregular, affecting one side. There is no clear distinction from severe chorea.

Myoclonic jerk: an extremely brief contraction of a muscle group leading to involuntary purposeless jerk of the affected limb.

Negative myoclonus: irregular sudden brief loss of muscle tone when a limb is held outstretched. The most common form is asterixis.

Tic: a stereotyped and irresistible repetitive action, normally a repeated purposeful action.

Tremor: rhythmical alternating movement.

Figure 24.1 There is a considerable overlap between chorea and athetosis; chorea and hemiballismus; and chorea and dystonia

WHAT TO DO

Look at the patient’s face.

• Are there any additional movements?

• Is the face expressionless?

Look at the patient’s head position.

Look at the arms and the legs.

• Note the position.

• Are there any abnormal movements?

Ask the patient to:

• smile

• close his eyes

• hold his hands out in front of him with his wrists cocked back (Fig. 24.2A)

Figure 24.2A Testing for tremor

• lift his elbows out sideways and point his index fingers at one another in front of his nose (Fig. 24.2B)

Figure 24.2B Testing for tremor

• perform the finger–nose test (as in Chapter 23).

If there is a tremor, note the frequency, the degree of the excursion (fine, moderate, large) and the body parts affected. Look for a tongue tremor (see Chapter 13).

Test eye movements (Chapter 9).

Test tone (Chapter 16).

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