title: Analysis of lower limb bradykinesia in Parkinson's disease patients.
abstract: OBJECTIVE
  Bradykinesia of the lower limb is an important limiting factor of the quality of life in parkinsonian patients. This study aims to develop quantitative measures of bradykinesia and to investigate the possible dissociation of amplitude and velocity measures and their dependence on movement direction during toe-tapping.
  
  
  METHODS
  Subjects included 39 patients with PD, as well as 14 healthy control subjects. A gyrosensor on the dorsum of a foot was used to measure ankle joint movement during toe-tapping. Four representations (root-mean square, mean peak, coefficient of variation in peaks, peak in the last 5 s) for each of amplitude and velocity and for each of plantar flexion and dorsiflexion movement of toe-tapping were investigated. Outcome measures were compared between patients and controls, and their correlations with clinical scores were investigated. Category distributions of outcome measures in patients were analyzed.
  
  
  RESULTS
  All outcome measures were smaller in patients than in controls (P < 0.001) and correlated well with clinical scores (P < 0.01). The mean peak of plantar-flexion velocity and variation of dorsiflexion velocity best represented the clinical toe-tapping score (r = 0.72-0.81). All clinical scores showed better correlation with velocity than with amplitude, and velocity was more affected (dispersed from the performance of controls) than amplitude. Movement directions had a slight effect on the results; specifically, the magnitude measures better correlated during plantar flexion and the variation measure better correlated during dorsiflexion.
  
  
  CONCLUSIONS
  The suggested measures represented clinical scores well and are expected to be helpful in clinical diagnosis of lower limb bradykinesia. Possible dissociations of amplitude and speed impairments and of movement directions in PD deserve further investigation.
authors: School of Biomedical Engineering, Konkuk University, Chonju, Korea.
authors: Ji-Won
authors: JW
authors: Kim
authors: Yuri
authors: Y
authors: Kwon
authors: Yu-Mi
authors: YM
authors: Kim
authors: Hong-Young
authors: HY
authors: Chung
authors: Gwang-Moon
authors: GM
authors: Eom
authors: Jae-Hoon
authors: JH
authors: Jun
authors: Jeong-Whan
authors: JW
authors: Lee
authors: Seong-Beom
authors: SB
authors: Koh
authors: Byung Kyu
authors: BK
authors: Park
authors: Dae-Kyu
authors: DK
authors: Kwon
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D018476:Hypokinesia / Q000209:etiology* / Q000503:physiopathology*; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D010300:Parkinson Disease / Q000150:complications* / Q000503:physiopathology*