Dissociation of cardinal motor signs in Parkinson's disease patients.

Most cardinal motor signs in Parkinson's disease (PD) are more pronounced on one side than on the other. Unusually, one type of cardinal motor sign is found on one side while other motor signs are more pronounced on the contralateral side, the so-called dissociation of motor signs. The aims of this study were to determine the frequency of motor sign dissociation and to study the clinical characteristics of the dissociation group. To this end, clinical characteristics including the Unified Parkinson's Disease Rating Scale, Mini-Mental State Examination, Non-Motor Symptom Questionnaire and Frontal Lobe Assessment Battery were analyzed for 411 patients during consecutive follow-up visits. Dissociation was noted in 29 (7.06%) of the 411 patients. Dissociation of tremor and rigidity-bradykinesia was the most common type of dissociation pattern (17/29). There were no significant differences in demographic factors and clinical profiles between the dissociation and control groups. We suspect that each cardinal motor sign is pathogenetically different. The presence of dissociation did not affect the natural history of PD.