Single-dose L-dopa response in early Parkinson's disease: measurements with optoelectronic recording technique.

Twenty-five patients with suspected Parkinson's disease were submitted to optoelectronic movement analysis with the Posturo-Locomotor-Manual (PLM) test before and 60 min after a single dose of L-Dopa. They were then examined clinically for diagnosis. Two patients were excluded due to L-Dopa intolerance. Seventeen of the remaining patients were classified as having Parkinson's disease. The movement time (MT) in the PLM test was increased for all these patients, and they improved their performance after L-Dopa. The degree of improvement was roughly proportional to the pretreatment augmentation of MT in comparison to healthy subjects of the same age. The PLM phase analysis showed a specific disability profile for each individual. Six patients were given diagnoses other than PD. Some improvement was found in one patient with suspected olivopontocerebellar atrophy and one patient with multiple brain injury. Two patients with progressive supranuclear palsy, one with suspected striatonigral degeneration, and one with functional disturbance deteriorated after L-Dopa. In conclusion, truly objective and fully reproducible evaluation of the motor performance before and after a single L-Dopa dose is easily accomplished with computer-assisted modern optoelectronic recording equipment. The technique is a valuable tool for the quantitative measurement of treatment effects and contributes to the differential diagnosis.