Objective measure of bradykinesia in parkinsonism by the maximal frequency of standardized, large pronation/supination movements.

OBJECTIVE: Bradykinesia in Parkinson's disease (PD) predominates in large movements. Traditional assessments use the UPDRS, a subjective and ordinal tool that does not rate movement scaling (hypometria). We have measured the maximum frequency of standardized large alternating elbow pronation/supination movements in patients with PD, hypothesizing a negative correlation with the UPDRS III score and with the delay since diagnosis.

MATERIALS/PATIENTS AND METHODS: We carried out a retrospective study on a convenience sample of 30 patients with idiopathic PD from Henri Mondor University Hospitals (Créteil, France), all assessed in the clinically defined OFF state by a single rater. Assessment included the maximal frequency of large (180°C) elbow pronation/supination movements (FLM), bilaterally, using a portable tool. Patients were also assessed on UPDRS III and bradykinesia sub-scores (UPDRS IIIb). We explored correlations (Pearson) between FLM and UPDRS III, UPDRS IIIb and time since diagnosis (TSD).

RESULTS: UPDRS III was 20.08±10.0 (mean±SD), TSD was 9.9±5.2 years and FLM were 0.75±0.27Hz and 0.94±0.25 on the more and less affected side respectively (strongly correlated with each other, r=0.80, p<0.0001). Correlations with UPDRS III scores and time since diagnosis for the more affected arm (resp less affected arm) were as follows FLM-UPDRSIII: r=-0.28; p=0.15 (r=-0.40; p=0.04); RLM-UPDRSIIIB, r=-0.48; p=0.01 (r=-0.36; p=0.06); FLM-TSD, r=-0.36; p=0.07 (r=-0.51; p=0.007).

DISCUSSION/CONCLUSION: These findings validate the maximal frequency of standardized 180°C pronation/supination movements as a clinical marker of the severity of parkinsonism. Intra- and inter-rater reliability and sensitivity to change of FLM still need to be investigated. FLM is easily usable in the clinic setting and might become a useful tool to optimize the monitoring of treatment effects and patient evolution.