Transcranial Brain Parenchyma Sonographic Findings in Familial and Sporadic Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neurons. Transcranial sonography (TCS) is a valuable tool for assessing deep brain structures. This study aimed to analyze TCS findings in both sporadic (sALS) and familial ALS (fALS) patients and compare them to healthy controls (HC).

This cross-sectional study included 278 patients with sALS and 31 patients with genetically confirmed fALS, and 93 age- and gender- matched HC. TCS was used to assess substantia nigra (SN) and brainstem raphe (BR) echogenicity and third ventricle diameter (TVD). Functional disability was evaluated using the ALS Functional Rating Scale-Revised.

BR hypoechogenicity was more frequent in fALS (41.9%) and sALS (37.4%) patients, compared to HC (10.8%) (p < 0.001). Right SN hyperechogenicity was observed in 28.1% of sALS, 16.1% of fALS, and 8.6% of HC (p = 0.004). Left SN hyperechogenicity was found in 33.5% of sALS, 29.0% of fALS, and 4.3% of HC (p = 0.004). SN hyperechogenicity findings on either side were highest in sALS (48.4%) compared to fALS (31.0%) and HC (13.3%) (p < 0.001), with a borderline difference between fALS and sALS (p = 0.08). BR hypoechogenicity and SN hyperechogenicity were more common in male patients. Increased TVD correlated with older age, later disease onset, bulbar onset, and lower MMSE scores.

TCS is an easily applicable and sensitive diagnostic tool that offers novel insights into several brainstem structures and identify significant differences in their echogenicity between ALS patients and healthy controls, while pointing out similar but not identical patterns of echogenicity in both ALS forms.