Geniospasm: A systematic review on natural history, prognosis, and treatment.

BACKGROUND: Geniospasm is a rare and generally benign movement disorder of the chin yet with potentially debilitating complications. Due to its rarity, previous literature was limited to only case reports or series with critical knowledge gap on its natural history, prognosis, and management. We aimed to establish the natural history, prognosis, and treatment for geniospasm. METHODS: A systematic review on case reports or series was performed with literature search on PubMed and Google Scholar, from inception through December 2021. The quality of the reports was assessed with low-quality articles excluded for analyses other than demographics. RESULTS: Forty-one articles were included for demographic analysis (n = 489) while forty articles for other analyses (n = 451). There was only slight male preponderance of this disease in our cohort (Male:Female = 1.2:1) with 98.6% having family history of geniospasm, 68.1% having onset below 1 year of age, 91.4% having emotional triggers of the symptoms, 25.7% having geniospasm in sleep, 100% involving mentalis muscles, 4.9% involving muscles adjacent to mentalis, 55.2% having regular paroxysms (≥1/week, but brief in 56.3% of the cases) and only 11.1% having complications. The paroxysms reduced with age, but complete remission only happened in 9.9%. Females (p = 0.010) and those without geniospasm in sleep (p = 0.048) were associated with good outcome of the disease. Geniospasm was usually refractory to treatment except for regular botulinum toxin injections. CONCLUSION: Generally, geniospasm improved with age but complete remission was rare. Considering our review limitations, our findings should be interpreted with caution. Future studies of higher evidence level are crucial.

The Elaborate Postural Display of Courting Drosophila persimilis Flies Produces Substrate-Borne Vibratory Signals.

Sexual selection has led to the evolution of extraordinary and elaborate male courtship behaviors across taxa, including mammals and birds, as well as some species of flies. Drosophila persimilis flies perform complex courtship behaviors found in most Drosophila species, which consist of visual, air-borne, gustatory and olfactory cues. In addition, Drosophila persimilis courting males also perform an elaborate postural display that is not found in most other Drosophila species. This postural display includes an upwards contortion of their abdomen, specialized movements of the head and forelegs, raising both wings into a "wing-posture" and, most remarkably, the males proffer the female a regurgitated droplet. Here, we use high-resolution imaging, laser vibrometry and air-borne acoustic recordings to analyse this postural display to ask which signals may promote copulation. Surprisingly, we find that no air-borne signals are generated during the display. We show, however, that the abdomen tremulates to generate substrate-borne vibratory signals, which correlate with the female's immobility before she feeds onto the droplet and accepts copulation.

Decreased temporal precision of neuronal signaling as a candidate mechanism of auditory processing disorder.

The sense of hearing is the fastest of our senses and provides the first all-or-none action potential in the auditory nerve in less than four milliseconds. Short stimulus evoked latencies and their minimal variability are hallmarks of auditory processing from spiral ganglia to cortex. Here, we review how even small changes in first spike latencies (FSL) and their variability (jitter) impact auditory temporal processing. We discuss a number of mouse models with degraded FSL/jitter whose mutations occur exclusively in the central auditory system and therefore might serve as candidates to investigate the cellular mechanisms underlying auditory processing disorders (APD).