INVESTIGATION OF SUBSTANTIA NIGRA HYPERECHOGENICITY BY TRANSCRANIAL SONOGRAPHY IN PATIENTS WITH ESSENTIAL TREMOR

Abstract

Objective: Essential tremor (ET) is the most common movement disorder. ET diagnosis may precede future Parkinson’s disease. Substantia nigra hyperechogenicity in transcranial sonography (TCS) is associated with Parkinson’s disease. The underlying etiology of substantia nigra hyperechogenicity remains unclear. In this study, we aimed to investigate the significance of the substantia nigra hyperechogenicity in patients with essential tremor. Methods: A total of 55 patients with ET and 60 matched controls underwent TCS. The hyperechogenic area was measured in the SN. Approximately ten years after their baseline TCS, all patients were inquired about their current condition, treatment, and medications to determine whether they had received a diagnosis of PD. Results: A total of 15 subjects were excluded due to insufficient image acquisition. The echogenic area of the SN ranged from 0.01 to 0.86 cm2 (mean 0.25±0.15) in the patient group and from 0.02 to 0.72 cm2 (mean 0.15±0.16) in the control group. Patients with ET had a significantly larger echogenic area than controls (p=0.001). 47% (26/55) of the patients have hyperechogenic SN, whereas only 15 % (9/60) of healthy controls have hyperechogenicity in the substantia nigra. None of the patients reported having a change in their diagnoses of ET. Conclusions: The results of this study show that SN hyperechogenicity is increased in patients with ET. Transcranial sonography may contribute to understanding the pathophysiology of ET.