Palatopharyngolaryngeal myokymia resembling "palatal myoclonus"

Demystifying the spontaneous phenomena of motor hyperexcitability

Possessing a discrete functional repertoire, the anterior horn cell can be in one of two electrophysiological states: on or off. Usually under tight regulatory control by the central nervous system, a hierarchical network of these specialist neurons ensures muscular strength is coordinated, gradated and adaptable. However, spontaneous activation of these cells and their axons can result in abnormal muscular twitching. The muscular twitch is the common building block of several distinct clinical patterns, namely fasciculation, myokymia and neuromyotonia. When attempting to distinguish these entities electromyographically, their unique temporal and morphological profiles must be appreciated. Detection and quantification of burst duration, firing frequency, multiplet patterns and amplitude are informative. A common feature is their persistence during sleep. In this review, we explain the accepted terminology used to describe the spontaneous phenomena of motor hyperexcitability, highlighting potential pitfalls amidst a bemusing and complex collection of overlapping terms. We outline the relevance of these findings within the context of disease, principally amyotrophic lateral sclerosis, Isaacs syndrome and Morvan syndrome. In addition, we highlight the use of high-density surface electromyography, suggesting that more widespread use of this non-invasive technique is likely to provide an enhanced understanding of these motor hyperexcitability syndromes.

Objective tinnitus associated with essential laryngeal myoclonus: report of two cases

We report on two patients with an objective tinnitus. In the first one, the objective tinnitus was unique as it was due to bilateral rhythmic contractions of the vocal cords. In the second, the objective tinnitus arose from Eustachian tube contractions and was associated with up and down movements of the larynx. In both patients, the abnormal laryngeal movement shared most of the characteristics of palatal or palatolaryngeal myoclonus and was thought to be laryngeal myoclonus. Its origin remained essential as all the investigations were negative.