title: Frequency analysis of lower extremity electromyography signals for the quantitative diagnosis of dystonia.
abstract: The purpose of this study was to develop an objective, quantitative tool for the diagnosis of lower extremity dystonia. Frequency domain analysis was performed on surface and fine-wire electromyography (EMG) signals collected from the lower extremity musculature of ten patients with suspected dystonia while performing walking trials at self-selected speeds. The median power frequency (MdPF) and percentage of total power contained in the low frequency range (%AUCTotal) were determined for each muscle studied. Muscles exhibiting clinical signs of dystonia were found to have a shift of the MdPF to lower frequencies and a simultaneous increase in the %AUCTotal. A threshold frequency of 70Hz identified dystonic muscles with 73% sensitivity and 63% specificity. These results indicate that frequency analysis can accurately distinguish dystonic from non-dystonic muscles.
authors.affiliation: Mayo Graduate School, Mayo Medical School and the Mayo Clinic Medical Scientist Training Program, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Shanette A
authors.initials: SA
authors.lastname: Go
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Krista
authors.initials: K
authors.lastname: Coleman-Wood
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA. Electronic address: kaufman.kenton@mayo.edu.
authors.forename: Kenton R
authors.initials: KR
authors.lastname: Kaufman
mesh_terms: D000293:Adolescent; D000328:Adult; D019540:Area Under Curve; D002648:Child; D004056:Differential Threshold; D004421:Dystonia / Q000175:diagnosis*; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: Dystonia; Electromyography; Frequency analysis; Lower extremity