PET and MRI detection of early and progressive neurodegeneration in spinocerebellar ataxia type 36

• Published in: Movement disorders Vol. 32; no. 2; pp. 264 - 273
• Main Authors: Aguiar, Pablo, Pardo, Julio, Arias, Manuel, Quintáns, Beatriz, Fernández‐Prieto, Montse, Martínez‐Regueiro, Rocío, Pumar, José‐Manuel, Silva‐Rodríguez, Jesús, Ruibal, Álvaro, Sobrido, María‐Jesús, Cortés, Julia
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.02.2017
• Subjects: Adult; Aged; ataxia; Brain Stem - diagnostic imaging; Brain Stem - metabolism; Brain Stem - pathology; Cerebellar Vermis - diagnostic imaging; Cerebellar Vermis - metabolism; Cerebellar Vermis - pathology; Cerebellum - diagnostic imaging; Cerebellum - metabolism; Cerebellum - pathology; Disease Progression; Female; Humans; Magnetic Resonance Imaging - methods; Male; Middle Aged; Movement disorders; MRI; neurodegeneration; Nuclear Proteins; PET; Positron-Emission Tomography - methods; preataxic stage; Severity of Illness Index; Spinocerebellar Ataxias - diagnosis; Spinocerebellar Ataxias - diagnostic imaging; Spinocerebellar Ataxias - metabolism; Spinocerebellar Ataxias - pathology; neurodegeneration; preataxic stage; ataxia; MRI; PET
• ISSN: 0885-3185; 1531-8257
• DOI: 10.1002/mds.26854

ABSTRACT Background The spinocerebellar ataxias (SCAs) form a clinically, genetically, and pathological heterogeneous group of autosomal‐dominant degenerative diseases. In particular, SCA36 is characterized by a late‐onset, slowly progressive cerebellar syndrome typically associated with sensorineural hearing loss. This study was aimed at analyzing the neurodegenerative process underlying SCA36 through fluorodeoxyglucose positron emission tomography (FDG‐PET) and MRI scans. Methods Twenty SCA36 patients underwent a study consisting of FDG‐PET and MRI scans. Clinical motor evaluation was performed through the Scale for the Assessment and Rating of Ataxia (SARA). FDG‐PET was carried out using a voxel‐by‐voxel and region‐of‐interest analysis. MRI evaluation was based on visual inspection and volumetric analysis. Results SARA ranged from 0 to 24.5 (4 patients asymptomatic, 3 with unspecific symptoms, and 13 with cerebellar signs). FDG‐PET revealed hypometabolism in the asymptomatic stage in the vermis and right cerebellar hemisphere. In the ataxic stage, hypometabolism spread to both cerebellar hemispheres and the brain stem. MRI was normal in asymptomatic and preataxic individuals and showed superior cerebellar vermis atrophy early in the ataxic stage, diffuse cerebellar atrophy some years into the disease course, and a pattern of olivopontocerebellar atrophy in the oldest patients. There was no significant cerebellar atrophy in patients younger than 50 years. Conclusions We present the first FDG‐PET study of SCA36 and one of the largest neuroimaging study of SCAs. Our results revealed neuronal dysfunctions in the vermis and right cerebellar hemisphere as soon as a decade before the onset of motor symptoms. In the ataxic stage, dysfunctions spread to both hemispheres and the brain stem. © 2016 International Parkinson and Movement Disorder Society.