Badihian, Negin

AbstractBackground and purposePrimary lateral sclerosis (PLS) is a neurodegenerative disorder that primarily affects the central motor system. In rare cases, clinical features of PLS may overlap with those of progressive supranuclear palsy (PSP). We investigate neuroimaging features that can help distinguish PLS with overlapping features of PSP (PLS‐PSP) from PSP.MethodsSix patients with PLS‐PSP were enrolled between 2019 and 2023. We compared their clinical and neuroimaging characteristics with 18 PSP–Richardson syndrome (PSP‐RS) patients and 20 healthy controls. Magnetic resonance imaging, 18F‐flortaucipir positron emission tomography (PET), quantitative susceptibility mapping, and diffusion tensor imaging tractography (DTI) were performed to evaluate eight brain regions of interest. Area under the receiver operating characteristic curve (AUROC) was calculated.ResultsFive of the six PLS‐PSP patients (83.3%) were male. Median age at symptom onset was 61.5 (52.5–63) years, and all had mixed features of PLS and PSP. Volumes of the pallidum, caudate, midbrain, and cerebellar dentate were smaller in PSP‐RS than PLS‐PSP, providing good discrimination (AUROC = 0.75 for all). The susceptibilities in pallidum, midbrain, and cerebellar dentate were greater in PSP‐RS compared to PLS‐PSP, providing excellent discrimination (AUROC ≥ 0.90 for all). On DTI, fractional anisotropy (FA) in the posterior limb of the internal capsule from the corticospinal tract was lower in PLS‐PSP compared to PSP‐RS (AUROC = 0.86), but FA in the superior cerebellar peduncle was lower in PSP‐RS (AUROC = 0.95). Pallidum flortaucipir PET uptake was greater in PSP‐RS compared to PLS‐PSP (AUROC = 0.74).ConclusionsRegional brain volume, tractography, and magnetic susceptibility, but not tau‐PET, are useful in distinguishing PLS‐PSP from PSP.

AbstractBackgroundYoung‐onset multiple system atrophy (YOMSA) is defined as the onset of multiple system atrophy (MSA) before the age of 40 years old. YOMSA is rare and there is much uncertainty of the phenotype and natural history in patients with YOMSA.ObjectiveThe objective is to evaluate the characteristics and disease course of patients with YOMSA.MethodsWe retrospectively reviewed medical records of patients with MSA who were evaluated at all Mayo Clinic sites from 1998 to 2021. We identified patients with YOMSA and evaluated clinical characteristics, autonomic function testing results, and disease course.ResultsOf 1496 patients with a diagnosis of clinically probable or clinically established MSA, 20 patients had YOMSA. The median age of onset was 39.1 (interquartile range [IQR] = 37.1, 40.1) years; 13 patients (65%) were male. MSA‐parkinsonism was the most common subtype (65%). The median duration of symptom onset to YOMSA diagnosis was 4.9 (IQR = 3.7, 9) years. At the time of medical record review, 17 patients were deceased with a median survival of 8.3 (IQR = 7, 10.9) years. Univariate analysis showed that initial onset of autonomic failure predicted unfavorable survival (hazard ratio = 2.89, P = 0.04) compared to those who presented with motor impairment only at onset. At the time of YOMSA diagnosis, composite autonomic severity score was available in 19 patients with a median of 5 (IQR = 4, 6.5).ConclusionsYOMSA resembles MSA in most aspects including phenotype and prognosis, although the diagnosis is usually delayed. The presence of autonomic failure at symptom onset may be a poor predictor for survival.