Neurologists must wake up to the importance of sleep

Sleep is a pillar of brain health, which has diagnostic, prognostic and therapeutic implications. Sleep should be systematically assessed in all neurological patients. Sleep education and research are essential for neurology, according to Prof. Claudio Bassetti (Bern University Hospital, Switzerland).

“Good sleep promotes attention, memory consolidation, executive functions, including decision making, emotional control and mood,” Prof. Bassetti explained [1]. Sleep also functions as a sensory threshold and possibly modulates pain. Sleep promotes motor learning, behaviour, performance, and well-being. Among the mechanisms by which sleep helps to achieve this are energy saving, protein synthesis, membrane repair, synaptic plasticity and brain clearance.

Synaptic plasticity allows sleep-dependent synaptic downscaling. Synaptic strength increases during the major wake phase, followed by a synaptic down-selection while asleep. The reason for this “renormalisation” is that synapses cannot multiply and synaptic activity cannot increase indefinitely. The other theory Prof. Bassetti mentioned was brain clearance (“detoxification”) of the brain: the notion that proteins, including toxic proteins like amyloid and tau, are removed during sleep. Sleep deprivation has been associated with tau as well as amyloid increase in the central nervous system.

Yet another reason why sleep is important for the brain is that it consolidates memories. Replay of memories during sleep promotes learning; sleep deprivation is associated with reduced cognitive performance.

One of the implications of these insights is that sleep-wake can be the first (or primary) manifestation of neurological disorders. Examples are REM sleep behaviour disorders and pontomedullary dysfunction as a sign of synucleinopathies, and hypersomnia following a paramedian thalamic stroke.

Another implication is that sleep-wake disturbances are frequent in many neurological disorders (especially in the advanced stages), such as stroke, Parkinson's disease, Alzheimer's disease, epilepsy, migraine, autoimmune and neuromuscular disorders. “In the assessment of neurological disorders, it is mandatory to consider sleeping disorders: they are very frequent,” said Prof. Bassetti. Sleep disturbances can also be risk factors and modulators of neurological disorders. Examples are sleep apnea, insomnia and long sleep as risk factors of stroke, and the association between sleepiness and sleep apnea and the risk of dementia. Sleep enhancement improves neurological disorders in animal models.

Sleep is one of the fields in neurology in which precise approaches have begun to be applied: precise sleep-wake medicine, concluded Prof. Bassetti. Examples are orexin agonists in narcolepsy and antagonists in insomnia. “This is only the beginning.”

1. Bassetti C. Sleep by the brain, for the brain: Implications for neurology. PLEN2, EAN Congress 2025, 21-24 June, Helsinki, Finland.

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Posted on 3 September 2025