(Objective) To investigate the relationship between sleep disorder and autonomic imbalance (AI) in dizziness cases diagnosed as having AI by clinical symptoms and inspections centered on the active standing test (Schellong test). (Method) A total of 27 who had clinical symptoms suggestive of AI and were diagnosed as having AI by the active standing test, and/or the responses to a questionnaire on AI of 237 patients who visited the specialized dizziness outpatient department and answered items for determination of the Pittsburgh sleep quality index (PSQI) were analyzed. The dizziness severity associated with AI was evaluated by the dizziness frequency and Dizziness handicap index (DHI). (Results) The average PSQI in the patients with AI was 8.2±3.5 (cutoff value of PSQI, 5.5), and 70.4% (19/27) in patients with AI with dizziness who were suspected as having some sleep disorder. The PSQI was not correlated with the age or severity of AI. The pulse rate increase in the standing test (r=0.45, p=0.019) and absolute value of SBP change after standing (r=0.45, p=0.018) were correlated with the PSQI (Conclusion) High-grade sleep disorder, similar to that in depression or primary insomnia was found in patients with AI, suggesting the possibility some sort of sleep disorder being associated with the onset and severity of orthostatic hypotension (OH) and postural tachycardia syndrome (POTS).
