Distinguishing clinical features of hyperkinetic disorders

Movement abnormalities can be dichotomised into the two broad categories of hypokinetic and hyperkinetic syndromes. The hallmark of hypokinesias is the loss of voluntary and automatic movements (akinesia), which is combined with slowness (bradykinesia) and stiffness or increased muscle tone (rigidity) in akinetic-rigid or parkinsonian syndromes (1). In contrast, hyperkinesias are manifested by abnormal, uncontrollable and unwanted movements. This term should not be confused with “hyperkinetic disorders” used in ICD-10 (2) to describe a behavioural abnormality, typically labelled attention deficit disorder with hyperactivity, occurring particularly in children and often associated with attention deficit and a tendency to move from one activity to another without completing any one. This is often associated with disorganized, ill-regulated, and scattered activity and thinking. This is not the only inconsistency between terminology in adult and childhood disorders, and efforts have been recently undertaken to unify the nosology and diagnostic recommendations in pediatric and adult movement disorders (3).