The term “movement disorders” has been coined for diseases characterized by abnormal or excessive movements occurring in conscious patients. “Extrapyramidal disorder” is an older classification of central motor disturbances not involving the corticospinal pathway. Involuntary movement can occur in a setting where there is also difficulty in initiating or executing voluntary movement. The commonest example of combined hyperkinetic and hypokinetic features is Parkinsonism, where tremor is frequently associated with bradykinesia and rigidity.
“Movement disorders” is used in two ways: (1) to describe a symptom or physical sign of involuntary movement; (2) to describe a syndrome in which abnormal movements occur. Abnormal movements may be the only manifestation of a disease [e.g., essential tremor (ET), hemifacial spasm (HS)], or they can be part of a constellation of deficits [e.g., Parkinson's disease (PD), Huntington's disease (HD), progressive supranuclear palsy (PSP), Creutzfeldt–Jakob disease (CJD)]. Frequently, there may be more than one type of movement disorder associated with a disease [e.g., chorea, dystonia, and tremor in HD and Wilson's disease (WD)] (see Table 1–1).
Table 1–1. Overlapping Signs in Some Movement Disorders |Favorite Table|Download (.pdf)
Table 1–1. Overlapping Signs in Some Movement Disorders
|Parkinson's Disease||Progressive Supranuclear Palsy||Multiple System Atrophy||Huntington's Disease||Wilson's Disease||Essential Tremor||Drugs (Dopaminergic Receptor Blockers)|
The first step when assessing a patient with a movement disorder is to designate the category of motor disturbance. The next step consists of determining whether the movement disorder appears in isolation or is associated with other neurological signs. Finally, clues bearing on the etiology are sought (hereditary or sporadic; primary, or secondary to a known neurological disease).
Some movement disorders are known to be associated with pathological changes in the basal ganglia (e.g., PD and HD), whereas the pathology in many others is still unclear [e.g., idiopathic torsion dystonia (ITD), ET and Gilles de la Tourette syndrome (GTS)]. ET is the commonest movement disorder, followed by PD, dystonia, and drug-induced movement disorders.
To categorize abnormal movements (e.g., chorea, tremor, ballism, myoclonus), one must be able to recognize the pattern of the involuntary movements. This can be difficult when combinations of different movements occur in the same individual. The term “dyskinesia” can be applied to any type of involuntary movement.
There are certain characteristics, which can help one arrive at a diagnosis:
Symmetry: asymmetric or symmetric
Nature: for example, stereotyped or nonstereotyped
Overflow to other body parts
Velocity: slow, intermediate, or fast
Rhythm: regular or irregular
Relation to general voluntary movement
Relation to specific tasks
Relation to posture
Relation to sleep
Associated sensory symptoms
Aggravating factors: for example, stress and anxiety
Precipitating factors: for example, alcohol and voluntary movement
Ameliorating factors: for example, sleep and relaxation.
Distractibility and consistency: to ...