Rapid Alternating Movement:
Dysdiadochokinesis is the clinical term for an inability to perform rapidly alternating movements. Dysdiadochokinesia is usually caused by multiple sclerosis in adults and cerebellar tumors in children. Note that patients with other movement disorders (e.g. Parkinson’s disease) may have abnormal rapid alternating movement testing secondary to akinesia or rigidity, thus creating a false impression of dysdiadochokinesia.
How to perform Rapid Alternating Movement exam:
Ask the patient to place their hands on their thighs and then rapidly turn their hands over and lift them off their thighs. Once the patient understands this movement, tell them to repeat it rapidly for 10 seconds. Normally this is possible without difficulty. This is considered a rapidly alternating movement.
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