Investigation of the Cardiac Autonomic Functions in Patients with Essential Tremor

Introduction: Essential tremor is a neurological disorder that causes involuntary shaking. The aim of this study was to examine cardiac autonomic functions in patients diagnosed with essential tremor, as previous studies have differed in their findings regarding whether cardiac autonomic functions are affected in essential tremor patients. Patients and Methods: The study included 32 patients diagnosed with essential tremor and 26 individuals without any diseases as the control group. Consensus criteria were used for the diagnosis of essential tremor. A clinical rating scale was utilized to measure the characteristics and degree of essential tremor. Based on this scale, patients were classified as having a mild, moderate, marked, or severe disability. An exercise treadmill test was performed in both the tremor and control groups. Chronotropic index values were used to evaluate the sympathetic system, and resting heart rate index values were calculated to evaluate the parasympathetic system. Heart rate recovery values were calculated at one, two, three, four, and five minutes after the exercise treadmill test. Results: The descriptive characteristics of the tremor and control groups were similar. The Chronotropic index values were statistically different between the tremor and control groups, as they were significantly decreased in the tremor group. This was evaluated as sympathetic incompetence. The resting heart rate index values did not differ significantly between the tremor and control groups at minutes one or two, but they were significantly higher in the tremor group at minutes three, four, and five. The parasympathetic activity was found to be insufficient in the later period. Conclusion: The findings suggest that cardiac autonomic functions may be affected in patients with essential tremor.