Identifying Cerebellum’s Structural Changes May Serve as Biomarker for Ataxia, Study Finds

Researchers at Italy’s IRCCS Santa Lucia Foundation have found that cerebellar atrophy can affect brain structures related to emotions, thinking and memory, which may in part explain ataxia symptoms. Their results suggest that identifying structural alterations in the cerebellum via imaging can help detect cerebellar degeneration and ataxia.

These observations in their study, “Impact of cerebellar atrophy on cortical gray matter and cerebellar peduncles as assessed by voxel-based morphometry and high angular resolution diffusion imaging,” which appeared in the journal Functional Neurology.

The cerebellum is the brain region that controls movement and motor tasks. More recently, scientists have learned that the cerebellum is also involved in cognition and emotions, though it’s not clear how this region is connected to these brain functions. Cerebellar atrophy can affect all regions connected to cerebellum. Therefore, studying the brain structure of patients with this condition might shed light on the cerebellum’s functional and structural connection to the rest of the brain.

In the present study, authors evaluated the occurrence of structural alterations in the brain due to cerebellar degeneration in a cohort of seven patients with cerebellar ataxia — two with spinocerebellar atrophy type 2, one with Friedreich’s ataxia, and four with idiopathic cerebellar ataxia.

Using imaging techniques and structural analyses, they observed that different regions of the brain — the caudate nucleus, cingulate gyrus and orbitofrontal cortex — showed a symmetrical decrease in the patients’ volume of gray matter compared with normal controls.

Together with the cerebellum, the caudate nucleus region is related to voluntary movements. The cingulate gyrus is involved in emotional control, memory retrieval and general cognition, while the orbitofrontal cortex is related to cerebellar activity. These observations suggested a functional connection among the cerebellum and the three brain regions.

“By comparing patients presenting general cerebellar atrophy with normal controls, we were able to investigate which cerebral regions were affected by their cerebellar atrophy,” the authors wrote.

Diffusion magnetic resonance imaging (dMRI) is a non-invasive technique that maps a tissue based on the ability of a water molecule to travel within the tissue. Researchers found a correlation between the dMRI values of one region of the cerebellum, the middle cerebellar peduncle, and ataxia total score and some of its subscores, such as kinetic functions and eye movement disorders.

Specifically, patients with low dMRI values had higher ataxia scores, while patients with high dMRI values had lower ataxia scores — suggesting that dMRI could be a useful imaging biomarker for cerebellar degeneration and ataxia.