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Intersubject variability and intrasubject reproducibility of the bereitschaftspotential
Author(s) -
Evidente Virgilio Gerald H.,
Caviness John N.,
Jamieson Bonnie,
Weaver Amy,
Joshi Neel
Publication year - 1999
Publication title -
movement disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.352
H-Index - 198
eISSN - 1531-8257
pISSN - 0885-3185
DOI - 10.1002/1531-8257(199903)14:2<313::aid-mds1017>3.0.co;2-1
Subject(s) - reproducibility , intraclass correlation , electromyography , wrist , scalp , coefficient of variation , concordance , physical medicine and rehabilitation , psychology , concordance correlation coefficient , medicine , audiology , anatomy , mathematics , statistics
We assessed the intersubject variability and intrasubject reproducibility of the bereitschaftspotential (BP). Twenty healthy volunteers performed extensions of their wrist in a self‐paced manner every 5–10 seconds. A surface electromyography (EMG) electrode was attached to the wrist extensor group of the dominant hand to record at least 100 wrist movements, and electroencephalography electrodes were placed over the scalp. Trials were performed at baseline, 15 minutes, 4 hours, and 4 weeks. Measures derived from the BP included area 1 (−2000 to −650 msec), area 2 (−650–0 msec), total area (area 1 + area 2), amplitude at −650 msec, amplitude at peak negativity prior to EMG onset, and amplitude at 0 msec (trigger). Our findings revealed different variability/reproducibility depending on the particular BP measure being analyzed. Using intraclass correlation coefficient (ICC) and concordance correlation coefficient (CCC) as measures of intrasubject reproducibility, area 2, amplitude at peak negativity prior to EMG onset, and amplitude at 0 msec produced the best values. We conclude that in studies that attempt to quantify BP changes before and after an intervention in the same group of subjects, the most reproducible BP measures are those pertaining to the late BP component.