neurologic disorders
Overview of Movement and Cerebellar Disorders
Classification of Movement and Cerebellar Disorders
Movement disorders are commonly classified as those with Decreased or slow movement (hypokinetic disorders) Increased movement (hyperkinetic disorders) Theclassic and most common hypokinetic disorderis Parkinson Disease None Hyperkinetic disordersrefer to Tremor None Myoclonus None Dystonias None Chorea, Athetosis, and Hemiballismus (including hemiballismus [rapid chorea] and athetosis [slow chorea]) Tic Disorders and Tourette Syndrome in Children and Adolescents None Stereotypies Akathisia Periodic Limb Movement Disorder (PLMD) and Restless Legs Syndrome (RLS) None However, this classification does not account for overlap between categories (eg, tremors that occur in Parkinson disease). Cerebellar disorders are sometimes considered hyperkinetic disorders often accompanied by axial, gait, and appendicular ataxia with or without central nystagmus, ocular saccadic dysmetria, and pursuit dysfunction. Hyperkinetic Disorders (see figure Rhythmic Nonrhythmic Rhythmic disordersare primarily tremors—regular alternating or oscillatory movements, which can occur mainly at rest, while maintaining a position, and/or during attempted movement. However, in some cases, a tremor, though rhythmic, is irregular, as occurs when tremor is associated with dystonic disorders. Nonrhythmic hyperkinetic disorderscan be Slow (eg, athetosis) Sustained (eg, dystonias) Rapid (eg, myoclonus, chorea, tics, hemiballismus) Rapid nonrhythmic hyperkinetic disorders may be Suppressible (eg, tics) Nonsuppressible (eg, hemiballismus, chorea, myoclonus) Athetosis and chorea may occur together as choreoathetosis. Chorea is the most characteristic movement disorder in Huntington Disease . Multiple motor and phonatory tics are the defining feature of Tic Disorders and Tourette Syndrome in Children and Adolescents . 