Primary sleep disorders seen at a Neurology service-based sleep clinic in India: Patterns over an 8-year period

There is an increasing awareness for recognition of sleep disorders in India; however, there is still a huge gap in the number of people suffering from various sleep disorders, in the community versus those visiting hospital clinics for the same. Ours is a neurology services-based sleep disorders clinic, which has evolved successfully over the last decade. In this study, we aimed to evaluate the changes in referral patterns and distribution of various sleep disorders in the patients presenting to the clinic. Materials and Methods: This is a retrospective chart review-based study on all patients seen over an 8-year period, divided into 2 groups comprising of patients seen during the first 4 years versus those seen over the next 4 years. Only those patients who had the sleep disorder as their presenting manifestation and those who had been formally interviewed with a pre-structured questionnaire detailing about the main features of the common sleep disorders according to the ICSD-R were included. Patients, in whom the sleep disorder could be clearly attributable to another neurological or systemic disorder, were excluded. Statistical analysis was carried out to identify the differences between the two groups as regards the distribution of various sleep disorders and other clinical data. Results: Among 710 patients registered in the clinic, 469 were included for analysis and 222 patients formed group 1 while 247 formed group 2. The main differences observed were in the form of a clear increase in the percentage of patients with sleep-related breathing disorders, sleep-related movement disorder, and the hypersomnias on comparison of distribution over the first 4 years versus the last 4 years; while a clear decline was seen in the number of patients with insomnia and parasomnias. A 3-fold increase was observed in the number of patients in whom polysomnography was obtained. Conclusion: The distribution of various sleep disorders as seen in a neurology service-based sleep clinic is demonstrated in this study. Increasing referrals for sleep-disordered breathing, restless legs syndrome, and fewer referrals for insomnia and parasomnias might reflect on changing physician and patient awareness in our community.