LAUSR

To the Editor: The Diagnostic and Statistical Manual of Mental Disorders-Five Edition (DSM-5) [1] defines hypersomnolence as: Ba broad diagnostic term and includes symptoms of excessive quantity of sleep, deteriorated quality of wakefulness, and sleep inertia (Criterion A).^ Furthermore, hypersomnia has been often clinically identified as a symptom in young patients with bipolar spectrum mainly with depression traits but never confirmed by instruments (Steinan et al., 2016). Moreover, during hypersomnia nocturnal polysomnography (PSG) demonstrates a normal to prolonged sleep duration, short sleep latency, and normal to increased sleep continuity. The distribution of rapid eye movement (REM) sleep is also normal. Sleep efficiency is mostly greater than 90%. Multiple sleep latency test (MSLT) is the gold standard for differential diagnosis in patients with hypersomnia and narcolepsy. Curiously, in the psychiatric assessment, the diagnosis of hypersomnolence is mainly made by taking the patient history except for only five subjects out of 25 patients with BP reported in the current literature [2]. The present case further highlights that a precise diagnosis and a comprehensive approach to the hypersomnolent patient in order to include psychiatric disorders into the differential diagnosis (e.g., to exclude psychiatric comorbidity for a diagnosis of any central nervous system hypersomnia) is mandatory. A 48-year-old woman was admitted at our Neurology Unit because of long-lasting history of hypersomnolence. The patient reported, during the last 4 months, abnormally long night sleep, difficult awakening in the morning, confusion, and disorientation. These episodes lasted between six daily hours till more than 2 days. General and neurological examination was normal. The patient did not report symptoms such as sleep paralyses/hallucinations or snoring. The patient referred a prolonged night sleep without interruption and night terror occurrence, particularly difficulty in awakening and persistent daytime sleepiness. She never complained about sudden loss of muscle tone such as cataplectic episodes neither hallucination. The Epworth Sleepiness Questionnaire showed a score of 16. Thus, from the clinical point of view, the diagnosis of narcolepsy with or without cataplexy was excluded according to the DSM-5 Criteria (347.01 DSM-5). She underwent extensive electro-clinical, neuropsychiatric, and imaging investigation. Routine and awake electroencephalograms were normal as well as 3T brain imaging. A PSG demonstrates normal sleep, except for its prolonged duration. Sleep apnea or periodic limb movement were not recorded. MSLT showed a mean sleep latency of 6.11 min (normal range 10–20 min) and two episodes of sleep-onset REM (SOREM) periods in Iolanda Martino and Antonella Bruni contributed equally to this work