Neuroimaging Pearls from the MDS Congress Video Challenge. Part 1: Genetic Disorders.

We selected several "imaging pearls" presented during the Movement Disorder Society (MDS) Video Challenge for this review. While the event, as implicated by its name, was video-centered, we would like to emphasize the important role of imaging in making the correct diagnosis. We divided this anthology into two parts: genetic and acquired disorders.

Braak's Unfinished Hypothesis: A Clinicopathological Case Report of α-Synuclein Peripheral Neuropathy Preceding Parkinsonism by 20 Years.

Background: α-synuclein aggregates in the form of Lewy bodies and Lewy neurites are the pathological hallmark of Parkinson disease (PD) and dementia with Lewy bodies (DLB). Autopsy studies suggest that α-synuclein aggregates appear in localized areas of the central nervous system before spreading in a sequential pattern from the brainstem to the cerebral cortex, known as the Braak hypothesis. Increased prevalence of peripheral neuropathy in PD is recognized, with multiple hypothesized mechanisms including α-synuclein deposition.

Extending the Phenotypic Spectrum Associated with Mutations: A Case of Dystonia.

Background: Mutations in the STIP1 homology and U-box containing protein 1 gene were first described in 2013 and lead to disorders with symptoms including ataxia and dysarthria, such as spinocerebellar autosomal-recessive ataxia type 16 (SCAR16), Gordon-Holmes syndrome, and spinocerebellar ataxia type 48. There have been 15 families described to date with SCAR16.

Cases: We describe a 45-year-old right-handed woman with dysarthria, ataxia, and cervical dystonia with SCAR16 with 2 compound heterozygous variants in the STIP1 homology and U-box containing protein 1 gene, and a family history significant for her 47-year-old sister with dysarthria and cognitive problems.

Antibody-Negative Paraneoplastic Limbic Encephalitis, Parkinsonism, Hypothermia, and Narcolepsy Associated with Endometrial Carcinoma.

Background: We describe the clinical and neuropathological features of a patient with T-cell-mediated paraneoplastic limbic encephalitis, parkinsonism, hypothermia, and narcolepsy-like presentation associated with endometrial carcinoma.

Objectives: This patient with prominent parkinsonism and narcolepsy broadens the phenotype of known paraneoplastic syndromes and demonstrates the importance of investigation for occult malignancy even in the absence of paraneoplastic antibodies.

Methods: This is a case report with diagnosis confirmed at postmortem.

How Do I Examine Rigidity and Spasticity?

Examination of tone (increased resistance to the passive movement of a joint) is a clinically useful and occasionally neglected part of the neurological examination. Rigidity and spasticity are two distinct types of hypertonia that arise from distinct anatomical pathways. The ability to differentiate between these two entities therefore gives important information regarding localization.