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Movement disorder has largely replaced the older term ‘Extrapyramidal disease’. A few movement disorders do arise outside the basal ganglia eg. myoclonus from the brain stem, cortex, or spinal cord, and painful legs/moving toes arise from the peripheral nervous system.

This large group of complex, sometimes bewildering, neurological disorders, is often highly treatable. However, an accurate diagnosis is mandatory before one can think of effective therapy. In this era of neurodiagnostic high–technology, there remains no way to diagnose an involuntary movement other than visual inspection. Words fail to express the subtle nuances which distinguish between various types of movements, and one can learn this art well only by examination of affected patients or videotapes. This article is an attempt to outline a clinical approach to the diagnosis of the common movement disorders.

Types of movement disorders
Movement disorders essentially have either less movement (hypokinesia) or excessive movement (hyperkinesia). Sometimes, there is a combination of both.

The Akinetic–Rigid syndromes
Hypokinesia bradykinesia or akinesia: Poverty of movement in speed or amplitude without any weakness or paralysis. The Hyperkinetic Dyskinetic syndromes
Hyperkinesias or Dyskinesias
A wide variety of abnormal, excessive involuntary movements further characterized according to their regularity, velocity and duration, as well as anatomical distribution, tremors, tics and stereotypies are regular and predictable movements while chorea flows irregularly from one body part to another without a predictable pattern. Myoclonus, clonictics and some tremors are rapid while dystonias and athetosis are slow and sustained, often with a twisting component.

Finally, several hyperkinesias have a tendency to involve certain body regions for example akathisia almost always affects the legs. Tics tend to be most prominent in the face, eyes and neck and dystonic movements occur in all body regions, but are particularly common in the neck muscles. Causes
Signs and symptoms Examination of hypokinesia and hyperkinesia
Patients are evaluated at rest during maintenance of a static posture and volitional activity. Study of speech and gait is also very helpful.

Patient at Rest: Sitting comfortably or lying supine. In hypokinetic disorders, one sees a lack of normal gesturing and spontaneous movements with a mask like face or rest tremor. Dystonias can be seen in positions which are seemingly at rest. Many other hyperkinesias are present at rest such as athetosis, Hemiballismus, chorea and tics. Patients with akathisia become restless and find it very difficult to sit quietly. Tics may be better seen when the patient feels he is not being observed. Myoclonus or a heightened startle reflex may be seen on suddenly clapping the hands.

Maintenance of a posture: Holding the hand outstretched may bring out a postural tremor or the sudden jerks of myoclonus. Dystonic patients also develop tremor (dystonic tremor) when they try to resist their dystonia. A hallmark of chorea is ‘Motor impersistence’ whereby patients are unable to maintain a posture without the superimposition of the random choric movements, eg. jack in the box tongue or milkmaid grip.

Execution of tasks
Many tasks are interrupted by hypokinesia and hyperkinesia.

Finger or foot tapping
Will be slow and cramped in hypokinesia and sloppy and overridden with additional movements in chorea or may precipitate a contorted spasm in dystonia.

Handwriting
Is useful since bradykinesia will cause a small and cramped Parkinsonian script (micrographia). Action tremor will cause a large, tremolos signature. Dystonia will induce irregular script and often the patient keep adjusting or even dropping the pen. Finger to nose task helps distinguish postural tremor from kinetic or end point tremor usually associated with cerebellar ataxia.

Speech
Allows the examiner to detect dysarthria, hypophonia and language and apraxic disorders, as well as mood and dementia. Talking often induces overflowing dystonic movements elsewhere in the body, apart from bringing out action, dystonia of the tongue, face or jaw muscles. On the other hand, patients with blepharospasm may have relief of their forced eyelid closure by talking. Those with hypokinetic disorders may exhibit monotonous speech with decreased amplitude (hypophonia) palilalia, transient speech arrests, or tachyphemia (rapid speech with no pausing between syllables). Hyperkinetic disorders like chorea, myoclonus and lingual dystonia can also impair speech.

Tone: Unlike spasticity, the increased tone of rigidity or cog wheeling, is seen in both flexor and extensor muscles during slow movements. Dystonic patients may have a fluctuating tone while chorea often has hypotonia.

Walking: Gait integrates and so tests numerous neuroanatomical systems. In hypokinesia, the patient has a hunched, flexed posture, with reduced arm swing. The steps are small and often the patient walks on the toes with a propulsive running gait. Alternatively, the patient may fall backwards, especially when pivoting.

The hyperkinesias may show a variety of gait abnormalities eg. a lilting stuttering dance like gait often accompanied by flail hypotonic limbs in chorea, foot and truck spasms in dystonias. Tics may abate during walking though.

Postural reflexes can be tested by the pull test, standing behind the patient and after a proper warning, giving a brisk pull on the shoulders. In the hypokinetic movement disorders they will take several steps backwards or even fall.
Diagnosis
Neuroimaging
Often MRI or CT scans show only non–specific mild to moderate cerebral atrophy, but they may show specific abnormalities in Huntington’s disease (caudate atrophy) OPCA (atrophy of the Pons and cerebellum), increased signal intensity in the putamen on T2 weighted images, (multiple system atrophy). MRI and CT scan are particularly useful in suggesting non degenerative secondary causes of movement disorders, like cerebrovascular accidents abscesses and tumors as well as calcium deposition, carbon monoxide intoxication. SPECT scanning is useful in corticobasal gangalionic degeneration, where focal parietal lobe hypoactivity can sometimes be detected.

EEG
May show epileptiform discharges in paroxysmal dyskinesias and myoclonic disorders, tremors can be characterized with tremorometer recording while EMG may help in dystonias especially with botulinum injection therapy.

Fluid and tissue analysis
Apart form basic electrolytes, CBC, LFT and TFTs, copper and serum ceruloplasmin levels are useful, as are fresh blood smears for neuroacabtgicttisus.

Neuropsychological tests
Are useful in making diagnoses of Huntingtion’s disease and Tourette syndrome, and also in guiding potential decisions regarding medication therapies.