Zee, David S.

Fatal familial insomnia (FFI) is a rare inherited prion disease characterized by sleep, autonomic, and motor disturbances. Neuro‐ophthalmological abnormalities have been reported at the onset of disease, although not further characterized. We analyzed video recordings of eye movements of 6 patients with FFI from 3 unrelated kindreds, seen within 6 months from the onset of illness. Excessive saccadic intrusions were the most prominent findings. In patients with severe insomnia, striking saccadic intrusions are an early diagnostic clue for FFI. The fact that the thalamus is the first structure affected in FFI also suggests its role in the control of steady fixation. ANN NEUROL 2021;89:823–827

This paper presents a classification and definitions for types of nystagmus and other oscillatory eye movements relevant to evaluation of patients with vestibular and neurological disorders, formulated by the Classification Committee of the Bárány Society, to facilitate identification and communication for research and clinical care. Terminology surrounding the numerous attributes and influencing factors necessary to characterize nystagmus are outlined and defined. The classification first organizes the complex nomenclature of nystagmus around phenomenology, while also considering knowledge of anatomy, pathophysiology, and etiology. Nystagmus is distinguished from various other nystagmus-like movements including saccadic intrusions and oscillations. View accompanying videos at https://journals.sagepub.com/doi/full/10.3233/VES-190658#supplementary-materials

AbstractBiallelic pathogenic variants in AARS2, a gene encoding the mitochondrial alanyl‐tRNA synthetase, result in a spectrum of findings ranging from infantile cardiomyopathy to adult‐onset progressive leukoencephalopathy. In this article, we present three unrelated individuals with novel compound heterozygous pathogenic AARS2 variants underlying diverse clinical presentations. Patient 1 is a 51‐year‐old man with adult‐onset progressive cognitive, psychiatric, and motor decline and leukodystrophy. Patient 2 is a 34‐year‐old man with childhood‐onset progressive tremor followed by the development of polyneuropathy, ataxia, and mild cognitive and psychiatric decline without leukodystrophy on imaging. Patient 3 is a 57‐year‐old woman with childhood‐onset tremor and nystagmus which preceded dystonia, chorea, ataxia, depression, and cognitive decline marked by cerebellar atrophy and white matter disease. These cases expand the clinical heterogeneity of AARS2‐related disorders, given that the first and third case represent some of the oldest known survivors of this disease, the second is adult‐onset AARS2‐related neurological decline without leukodystrophy, and the third is biallelic AARS2‐related disorder involving a partial gene deletion.