Background l-dopa is the standard treatment for Parkinson’s disease, but the response is variable.

Aim Systematic review of papers reporting the l-dopa response (motor response and/or complications) in pathologically confirmed Parkinson’s disease.

Results 467 cases of pathologically confirmed Parkinson’s were identified: 60.2% male, age at disease onset 63.3 years (SD 10.3), age at death 76.7 years (SD 7.8). Data on a graded l-dopa response were available in 411 cases (88.0% of 467). The motor response was excellent in 148/411 cases (36.0%), good in 179/411 (43.6%), moderate in 51/411 (12.4%) and poor/absent in 33/411 (8.0%). Data about motor complications were available for 161 patients: 71/161 (44.1%) had motor fluctuations and 89/161 (55.3%) had dyskinesia. Comorbid brain pathology was evaluated in 251/411 cases (61.1%), and was present in 148/251 (59.0%): cerebrovascular in 65/148 (43.9%), Alzheimer’s in 55/148 (37.2%), amyloid angiopathy in 18/148 (12.2%), and diffuse Lewy body disease in 10/148 (6.8%). Data linking the graded l-dopa response to comorbid pathologies were available in only 17 cases, of whom 8/17 (47.1%) had a good/excellent response.

Conclusion There is variation in the l-dopa response in pathologically confirmed Parkinson’s disease. The limited available information suggests a possible association of motor response to comorbid brain pathology.