Secondary hypersomnia as an initial manifestation of neuromyelitis optica spectrum disorders.

The identification of AQP4-IgG, a specific and pathogenic antibody of NMO/SD has led to a broadening of the clinical spectrum of manifestations of NMO/SD including the presence of encephalic symptoms. Lesions are often distributed on peri­ependymal area and sometimes affected the diencephalon leading to sleep disorders. We report a case of hypersomnia with polysomnographic documentation during the first attack of NMO/SD. Brain MRI revealed bilateral hypothalamic lesions around the third ventricle, whereas optic nerves and spinal cord were intact. The record of the nocturnal video-polysomnography followed by multiple sleep latency tests (MSLT) revealed an abnormal shortened sleep period with a single sleep onset in REM allowing secondary central hypersomnia diagnosis. The recovery of hypersomnia was complete within few months without psychostimulant treatment and the diencephalic lesion disappeared. Thus, diencephalic form of NMO/SD seems to cause narcolepsy or non-narcoleptic central hypersomnia and have a good recovery.

Can we still dream when the mind is blank? Sleep and dream mentations in auto-activation deficit.

Bilateral damage to the basal ganglia causes auto-activation deficit, a neuropsychological syndrome characterized by striking apathy, with a loss of self-driven behaviour that is partially reversible with external stimulation. Some patients with auto-activation deficit also experience a mental emptiness, which is defined as an absence of any self-reported thoughts. We asked whether this deficit in spontaneous activation of mental processing may be reversed during REM sleep, when dreaming activity is potentially elicited by bottom-up brainstem stimulation on the cortex. Sleep and video monitoring over two nights and cognitive tests were performed on 13 patients with auto-activation deficit secondary to bilateral striato-pallidal lesions and 13 healthy subjects. Dream mentations were collected from home diaries and after forced awakenings in non-REM and REM sleep. The home diaries were blindly analysed for length, complexity and bizarreness. A mental blank during wakefulness was complete in six patients and partial in one patient. Four (31%) patients with auto-activation deficit (versus 92% of control subjects) reported mentations when awakened from REM sleep, even when they demonstrated a mental blank during the daytime (n = 2). However, the patients' dream reports were infrequent, short, devoid of any bizarre or emotional elements and tended to be less complex than the dream mentations of control subjects. The sleep duration, continuity and stages were similar between the groups, except for a striking absence of sleep spindles in 6 of 13 patients with auto-activation deficit, despite an intact thalamus. The presence of spontaneous dreams in REM sleep in the absence of thoughts during wakefulness in patients with auto-activation deficit supports the idea that simple dream imagery is generated by brainstem stimulation and is sent to the sensory cortex. However, the lack of complexity in these dream mentations suggests that the full dreaming process (scenario, emotions, etc.) require these sensations to be interpreted by higher-order cortical areas. The absence of sleep spindles in localized lesions in the basal ganglia highlights the role of the pallidum and striatum in spindling activity during non-REM sleep.

Sleep and rhythm consequences of a genetically induced loss of serotonin.

BACKGROUND: A genetic deficiency in sepiapterin reductase leads to a combined deficit of serotonin and dopamine. The motor phenotype is characterized by a dopa-responsive fluctuating generalized dystonia-parkinsonism. The non-motor symptoms are poorly recognized. In particular, the effects of brain serotonin deficiency on sleep have not been thoroughly studied. OBJECTIVE: We examine the sleep, sleep-wake rhythms, CSF neurotransmitters, and melatonin profile in a patient with sepiapterin reductase deficiency. PATIENT: The patient was a 28-year-old man with fluctuating generalized dystonia-parkinsonism caused by sepiapterin reductase deficiency. METHODS: A sleep interview, wrist actigraphy, sleep log over 14 days, 48-h continuous sleep and core temperature monitoring, and measurement of CSF neurotransmitters and circadian serum melatonin and cortisol levels before and after treatment with 5-hydroxytryptophan (the precursor of serotonin) and levodopa were performed. RESULTS: Before treatment, the patient had mild hypersomnia with long sleep time (704 min), ultradian sleep-wake rhythm (sleep occurred every 11.8 +/- 5.3 h), organic hyperphagia, attentionlexecutive dysfunction, and no depression. The serotonin metabolism in the CSF was reduced, and the serum melatonin profile was flat, while cortisol and core temperature profiles were normal. Supplementation with 5-hydroxytryptophan, but not with levodopa, normalized serotonin metabolism in the CSF, reduced sleep time to 540 min, normalized the eating disorder and the melatonin profile, restored a circadian sleep-wake rhythm (sleep occurred every 24 +/- 1.7 h, P < 0.0001), and improved cognition. CONCLUSION: In this unique genetic paradigm, the melatonin deficiency (caused by a lack of its substrate, serotonin) may cause the ultradian sleep-wake rhythm.