Fig. 3

Electrophysiological findings from case 6. a EEG/EMG polygraphy showing on a 1 s epoch the irregular myoclonic jerks, consisting of small duration EMG discharges < 50 ms, demonstrating frequent co-activation of forearm antagonists with occasional simultaneous co-contraction of intrinsic hand muscles. b Averaged data obtained with the technique of CC with the tremorogenic activity from the R EDC used as reference (note the auto-correlation for the R EDC is 1). Spiky biphasic transients appear in the contralateral frontocentral EEG channel preceding the peak of the autocorrelation findings from the EDC by a few milliseconds. Two minutes of this jerky activity were used on the analysis. Please note the dotted lines indicate the 95% confidence interval. The cortico-muscular latencies are shown at a slower sweep time in the relevant Additional file 1. ADM = abductor digiti minimi, APB = abductor pollicis brevis, FCU = flexor carpi ulnaris, EDC = extensor digitorum communis