Hypokinetic disorders

The basal ganglia are a group of subcortical nuclei which are components of modular circuits involved in many cortical functions. They have received considerable attention from basic scientists and clinicians alike because of their prominent involvement in movement disorders, a spectrum of diseases including disorders which are characterized by poverty of movement (hypokinetic disorders), as well as disorders characterized by excess movement (hyperkinetic disorders). It has become clear in recent years that most basal ganglia disorders are not restricted to motor disturbances, but involve cognitive and emotional features as well. 

Unusual neurological reactions have been observed in some patients, generally when combinations of drugs (often including maprotiline) have been used (67). The symptoms were ataxia, akathisia, hypokinetic disorders of speech and motion, a dream-like state, and transiently impaired memory. 

In hypokinetic disorders, the discharge of efferent striatal neurons is diminished in the direct and increased in the indirect way, so that an inhibition of thalamocortical connections originates from a... 

Parkinson s disease (PD) is a hypokinetic movement disorder 766 Huntington s disease is a hyperkinetic movement disorder 771 Wilson s disease is a disease of copper accumulation 773 Dystonia is characterized by sustained muscle contractions 775 Many drugs and toxins induce movement disorders 776... 

Diseases of the basal ganglia are essentially characterized by abnormal motor activity. Based on the type of motor problem, diseases of the basal ganglia can be classified into hypokinetic or hyperkinetic groups. Hypokinetic basal ganglia disorders include PD, in which the amplitude and velocity of voluntary movements are diminished or, in extreme cases, non-existent. 

Found at the other end of the spectrum are the hyperkinetic basal ganglia disorders, which are represented by HD and essential tremor. In these two conditions, excessive abnormal movements such as chorea or tremor are superimposed onto and interfere with normal voluntary movements. Although hyperkinetic basal ganglia disorders are probably as diverse as hypokinetic basal ganglia disorders, their specific disease markers such as gene mutations, which exist for several of the hyperkinetic syndromes create more accurate, less problematic, classifications. 

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