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

Abstract

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. 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). UPDRS III was 20.08 ± 10.0 (mean ± SD), TSD was 9.9 ± 5.2 years and FLM were 0.75 ± 0.27 Hz 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). 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.