Dopa-responsive postural tremor in Parkinson's disease

In the present study postural tremor of the hands was assessed in 20 patients with idiopathic Parkinson's disease. In 16 cases postural tremor was bilateral. Clinical rating and spectral analysis of accelerometry and electromyography were performed with and without loading of the limb. All assessments were done before and after administration of levodopa. Accelerometry disclosed different types of postural tremor. In 27 hands a postural tremor oscillating in the frequency-band of rest-tremor was found (Type I). In 9 hands postural tremor occurred without corresponding rest tremor or with a different peak frequency (Type II). Type II tremor was further differentiated according to the presence (4 hands) or absence (5 hands) of peripheral components. Tremors with peripheral components showed slowing of peak frequency with weight load and partly lack of EMC synchronisation. All types of postural tremor responded well to levodopa challenge.