Figure 1
Myoclonus Recorded on Surface EMG in the Right Upper Limb and Accelerometer (Acc) Attached to the Right Index Finger. Some arrhythmic myoclonic jerks are shown with an arrow. Note the tremor-like postural irregular rhythmic myoclonus (*) in (B). (A) Rest; (B) extension of wrist; (C) drawing a spiral. Trap, trapezius; Bic, biceps; ECR, extensor carpi radialis; FCR, flexor carpi radials; FDI, first dorsal interosseous.
Figure 2
Jerk-Locked EEG–EMG Back Averaging (JLBA) in Patient 1 with Two Series Comprising a Total of 200 Myoclonic Bursts Registered in the Right First Dorsal Interosseous (FDI). There is no evidence of a pre-myoclonic potential on EEG recordings.
Video 1
Patient in a Sitting Position with Myoclonic Jerks of the Upper and Lower Limbs during Rest, while Maintaining Posture, and during Action. The myoclonic jerks interfered with holding a glass of water and pouring water from one glass into another. Dystonic posturing of both hands in an outstretched and flexed posture of the arms can be seen. During writing with the right hand, dystonic posturing of the first and second fingers and hyperextension of the wrist is also seen. The following facial features can be observed: thin upper lip, smooth philtrum, telecanthus, and long face.
Video 2
Patient in a Sitting Position with Myoclonic Jerks in the Right Upper Limb during Rest and in the Left Upper Limb during Posture. Myoclonic jerks get worsened with various actions. With the arms held up and elbows in a flexed posture, dystonic posturing can be seen in the left hand. When writing, dystonic posturing of the right thumb and index finger as well as hyperextension of right wrist can be seen together with associated dystonic posturing of the left hand. Drawing a spiral also shows dystonic posturing of the left hand. No remarkable findings are noted during walking. A triangular face, smooth philtrum, and plump nose are the prominent facial features.