Reverse Sleep State Misperception: a Rare Clinical Presentation in Sleep Clinics

The difference between subjective and objective duration of sleep is known as sleep state misperception. Many patients with sleep disorders perceive periods of objective sleep as waking subjectively. However, people rarely perceive objective wakefulness periods as sleep, known as reverse sleep-state misperception or wake-state misperception. A middle-aged male patient presented with primary complaints of snoring since 10–15 years. His subjective sleep duration was 6–7 h; however, polysomnography (PSG) found a sleep duration of 3–4 h only. This finding was consistent over two separate PSG nights. His Apnea–Hypopnea Index was either around or within normal limits in both PSG nights. His sleep diary schedule and subjective account of PSG nights were also comparable, thus mitigating any significant difference between home and laboratory differences. This phenomenon may be explained by exaggerated mesograde amnesia during the sleep period as well as ‘alpha sleep’. However, further research is required to elucidate the prevalence of the same, its pathophysiology and clinical importance.