PMC6411466_01
Video Demonstrating Key Clinical Features. Segment 1. The patient had reduced facial expression and blink rate, and speech was hypophonic and monotonous. A continuous tremor of the tongue and lips was observed. The tongue tremor transiently subsided when protruded, following which it recurred. A similar re-emergence was observed when the tongue was retracted and placed at rest. There was no rest tremor or postural tremor of either of the upper limbs. A continuous distal rest tremor was observed in the right leg. The patient had asymmetrical bradykinesia. Gait was slow with a reduction in bilateral arm swing. Segment 2. Evaluation in the 48 hours OFF state 8 months after stopping levosulpiride. The patient had very minimal hypomimia, and speech was normal. There was no tongue, lip, or lower limb tremor. Bradykinesia was negligible and gait was relatively normal.
.jpg
PMC6411466_01_.jpg
v01
Surface electromyography of the genioglossus (Figure 1) revealed a 5 Hz re-emergent tremor of the tongue. A latency of 5.5 seconds was observed between the rest tremor and re-emergence when the tongue was protruded (Figure 1A), and a latency of around 3.5 seconds was observed prior to re-emergence when the tongue was at rest.