Skip to main content
Fig. 1 | Orphanet Journal of Rare Diseases

Fig. 1

From: Ataxia, dystonia and myoclonus in adult patients with Niemann-Pick type C

Fig. 1

Electrophysiological characteristics of patient number 2. Left Panel: 6 s of raw EEG data with four left sided EMG channels, 2 and 3 are biceps and triceps, 4 and 5 are wrist flexor and extensor muscles. EEG montage: average reference. Note the multiple small myoclonic discharges, mostly in distal muscles, with small EMG burst duration and synchronous activation of agonists and antagonists. Background EEG pattern is normal without signs of epileptiform activity. Right Panel: coherence analysis (upper panels) shows significantly increased coherence from 14 to 28Hz, with also increased coherence around the myoclonus discharge frequency (around 4Hz). The red line is the threshold for significant coherence. The phase plot shows a linear decrease in phase from 14-28Hz (EEG leads EMG), with a calculated corticomuscular conduction time of 20,7 ms. The analysis is based on a segment of 180 s with frequently occurring myoclonus during rest. The lower panels show the result of back-averaging on the same segment. The average was based on 242 segments, with 75 ms pre-EMG onset and 25 ms post-EMG onset depicted. In the mapping view (view from above) a clear positive-negative potential field can be seen in the right centroparietal area. The positive peak is maximal at 23 ms before myoclonus onset

Back to article page