Cerebellar atrophy is frequently associated with non-paraneoplastic sensory neuronopathy

Abstract

Sensory neuronopathies (SN) are peripheral nervous system disorders associated with degeneration of dorsal root ganglion neurons. Despite the evidence of a defective proprioceptive sensory input in SN, the prominent gait and truncal ataxia raises the question of a concomitant involvement of the cerebellum. Objective: To evaluate cerebellar atrophy in SN. Method: We analyzed MRI-based volumetry of anterior lobe (paleocerebellum) and total cerebellum in patients with non-paraneoplastic chronic SN and compared to age-and gender-matched controls. Results: Cerebellum and anterior lobe MRI volumetry were performed in 20 patients and nine controls. Mean anterior lobe and cerebellar volume were not statistically different. Three patients (15%), however, had an abnormal anterior lobe and cerebellar volume index (values outside 2.5 standard deviations). One of them also had a specific atrophy of the anterior lobe. All these patients had infectious or dysimmune associated SN. Conclusion: Cerebellar atrophy is infrequently associated with SN, but can be found in some patients with SN related to infectious or immune mediated conditions. It can be more prominent in the anterior lobe and may contribute to the ataxia seen in these patients. Key words: cerebellar atrophy, cerebellar volume reduction, magnetic resonance imaging, sensory neuron disease, sensory neuronopathy Atrofia cerebelar não é um achado frequente em pacientes com neuronopatia sensi tiva não paraneoplasica RESUMO Neuronopatias sensitivas (NS) são distúrbios do sistema nervoso periférico associados com a degeneração dos neurônios do gânglio da raiz dorsal. Apesar da evidência de um defeito das aferências proprioceptivas, a ataxia proeminente da marcha e do tronco levanta a questão de uma participação concomitante do cerebelo. Objetivo: Avaliar a atrofia cerebelar nas NS. Método: Foi analisada volumetria pela ressonância magnética do cerebelo total e do lobo anterior (paleocerebelo) em pacientes com NS crônica não-paraneoplásica e comparada a controles com idades e sexos correspondentes. Resultados: A volumetria do cerebelo e lobo anterior foi realizada em 20 pacientes e nove controles. As médias do volume cerebelar e do lobo anterior não foram estatisticamente diferentes. Três pacientes, entretanto, tiveram um valor anormal do índice de volume cerebelar e do lobo anterior (valores fora de 2,5 desvios-padrão). Um deles tinha inclusive uma atrofia específica do lobo anterior. Todos esses pacientes tinham NS associada a doenças infecciosas ou disimunes. Conclusão: Atrofia cerebelar é raramente associada com SN, mas pode ser encontrada em alguns pacientes com NS relacionada com doenças infecciosas ou imunológicas. Esta atrofia pode ser mais proeminente no lobo anterior e pode contribuir para a ataxia observada nestes pacientes.

Neuroimaging in Sensory Neuronopathy

“…Cerebellar atrophy has been considered a rare finding in SN patients, but it is possibly overlooked. Damasceno et al used a semiautomated method to measure volumes of the whole cerebellum (CEV) as well as the anterior lobe of the cerebellum (ALV). These values were then normalized to whole brain volume and compared between healthy controls and patients.…”

The Intersection Between Cerebellar Ataxia and Neuropathy: a Proposed Classification and a Diagnostic Approach

“…Sensory or sensorimotor neuronopathies are found in degenerative causes of cerebellar diseases such as SCA3 and SCA2, where there is widespread protein deposition that leads to degeneration, including central pathways and the cell body of peripheral nerves. On the other hand, autoimmune and idiopathic sensory neuronopathies are sometimes associated with cerebellar atrophy [3]. In these cases, despite the evidence of a defective proprioceptive input, there is also prominent appendicular ataxia, dysarthria, and nystagmus, indicating a specific cerebellar involvement.…”