# Transcranial Sonography Characteristics of Cerebellar Neurodegenerative Ataxias

## TL;DR

This study uses transcranial sonography to identify brain characteristics in patients with cerebellar ataxias, linking imaging findings to clinical symptoms and disease progression.

## Contribution

The study provides novel TCS-based insights into cerebellar ataxias, linking imaging features to extrapyramidal signs and brain atrophy.

## Key findings

- Substantia nigra hyperechogenicity was found in 79.7% of patients and correlated with dystonia, rigidity, and dyskinesia.
- Third and fourth ventricle enlargement was common, with the fourth ventricle size correlating with ataxia severity.
- Raphe discontinuity was associated with depression in patients with cerebellar ataxias.

## Abstract

Cerebellar neurodegenerative ataxias are a group of disorders affecting the cerebellum and its pathways with different neurological structures. Transcranial sonography (TCS) has been used for the evaluation of brain parenchymal structures in various diseases because of its fast and safe utilization, especially in neuropsychiatric and neurodegenerative diseases. The aim of our study was to investigate TCS characteristics of patients with neurodegenerative cerebellar ataxias. In our study, we included 74 patients with cerebellar degenerative ataxia; 36.5% had autosomal dominant onset, while 33.8% had sporadic onset. Standardized ultrasonographic planes were used for the identification of brain structures of interest. The SARA, INAS, neuropsychological and psychiatric scales were used for the further clinical evaluation of our study participants. The brainstem raphe was discontinued in 33.8% of the patients. The substantia nigra (SN) hyperechogenicity was identified in 79.7%. The third and fourth ventricle enlargement had 79.7% and 45.9% of patients, respectively. A positive and statistically significant correlation was found between SN hyperechogenicity with dystonia (p < 0.01), rigidity and dyskinesia (p < 0.05). The higher SARA total score is statistically significantly correlated with the larger diameter of the III (r = 0.373; p = 0.001) and IV ventricles (r = 0.324; p = 0.005). In such patients, the echogenicity of substantia nigra has been linked to extrapyramidal signs, and raphe discontinuity to depression. Furthermore, ataxia and its clinical subtypes have positively correlated with the IV ventricle diameter, indicating brain atrophy and brain mass reduction.