Differential Diagnosis of Tremor

Psychogenic tremor is typically complex, with rest, postural, and action components, and often accompanies other features of psychogenic movement disorders.2 Recommendations from Others The consensus statement of the Movement Disorder Society lists 95 causes for tremor, but does not specify which causes are most common in primary care.7 Tremors can be categorized into three classes according to clinical presentation: (1) postural-action tremors, which include enhanced physiologic tremor, essential tremor, primary writing tremor, other extrapyramidal disorders (e.g., Parkinson's disease, Wilson's disease, dystonia), cerebellar disease, and peripheral neuropathy; (2) intention tremors (cerebellar outflow), which include cerebellar disease, multiple sclerosis, midbrain stroke, and midbrain trauma; and (3) rest tremors, which include Parkinson's disease, parkinsonian syndromes, midbrain (rubral) tremor, Wilson's disease, and severe essential tremor.2 Clinical Commentary To get a sense of the prevalence of tremor in the primary care setting, one has to extrapolate from data based on an exclusively white Italian population,1 an older Spanish population,4 or patients with Parkinson's disease.5 Although these data do not provide a multi-ethnic sense of tremor in primary care, we learn that the prevalence of tremor increases with age; that the more common tremors include exaggerated physiologic tremor, essential tremor, and parkinsonian tremor; and that there may be factors causing or contributing to the severity of tremor (Table 12).