MODULE 1 Flashcards
What are Sleep-Wake Disturbances (SWDs) and how prevalent are they in neurological and psychiatric disorders?
SWDs are disruptions in the sleep-wake cycle. They are extremely common in patients with neurological and psychiatric disorders.
How are SWDs linked to neurological and psychiatric functions?
SWDs are connected to the neurobiology of sleep and share overlapping neuronal networks and neurotransmitter systems.
What brain regions are involved in the control of sleep and wakefulness?
The hypothalamus, brainstem, thalamus, and basal forebrain are key brain regions involved.
Which brain structure serves as the master clock for circadian rhythms?
The suprachiasmatic nucleus (SCN) in the hypothalamus.
What neurotransmitters promote wakefulness and alertness?
Acetylcholine, norepinephrine, dopamine, histamine, and serotonin.
What is the role of the ascending reticular activating system (ARAS) in wakefulness?
The ARAS is a major pathway for maintaining wakefulness, sending projections to the thalamus and cortex.
Which brain region inhibits wake-promoting areas to promote sleep?
The ventrolateral preoptic nucleus (VLPO) in the hypothalamus.
What happens to neurotransmitters like serotonin and norepinephrine during sleep?
They are reduced during sleep.
What is the ‘depotentiation’ hypothesis in memory consolidation during sleep?
It suggests that local neuronal assemblies activated during learning are weakened or pruned during sleep to create space for new learning while preserving memory traces.
How does sleep contribute to memory integration and organization?
Sleep-induced reactivation and transfer of information across distributed cortical networks connect related pieces of memory into a more coherent and consolidated form.
When does neural network reactivation, promoting memory consolidation, occur during sleep?
During both rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep.
What is an enduring memory trace?
It is the long-lasting memory representation that is preserved after depotentiation during sleep.
How is insomnia defined?
Insomnia is defined by subjective complaints of prolonged sleep latency, difficulties to maintain sleep, or early morning awakening, with negative daytime consequences.
What is the prevalence of chronic insomnia?
Chronic insomnia affects over 10% of the population and contributes to the risk or severity of various disorders.
How is the diagnosis of insomnia made?
The diagnosis is based on subjective complaints, but polysomnography (PSG) can be useful to rule out secondary forms and provide objective sleep measures.
What is the “master clock” in the circadian system?
The suprachiasmatic nuclei serve as the mammalian “master clock” that synchronizes cell-autonomous circadian clocks in various cells of the brain and body.
Why are disturbances of circadian functions common in neuropsychiatric disorders?
Circadian dysregulation is frequently observed in neuropsychiatric disorders like depressive disorders, stroke, Alzheimer’s disease, Parkinsonism, RLS, and traumatic brain injury.
How can specific interventions targeting the circadian system benefit neuropsychiatric disorders?
Interventions such as sleep deprivation and intensive light therapy have been shown to improve symptoms in mood disorders and Alzheimer’s disease, while behavioral circadian reinforcement can enhance well-being in elderly individuals.
How do polymorphic variations of clock genes contribute to psychopathology?
Polymorphic variations of clock genes may contribute to bipolar disorder, either through causative involvement or altered responses to external “zeitgebers” like light-dark cycles.
What detrimental effects can sleep loss and disturbances have on neuronal function?
Sleep loss may lead to diminished clearance of toxic substances in the brain and contribute to inflammation associated with these disorders.
What does SDB stand for, and what does it include?
SDB stands for sleep-disordered breathing, which includes various phenotypes like snoring, OSA, CSA, CSR, and hypoventilation syndromes.
What are the neuropsychiatric consequences of sleep-disordered breathing?
Neuropsychiatric consequences include excessive daytime sleepiness (EDS), fatigue, insomnia, and neuropsychiatric symptoms.
What are some potential treatments for OSA?
Continuous positive air pressure (CPAP) treatment can reduce blood pressure, improve EDS, and prevent the progression of mild OSA in obese patients.
What are central hypersomnias characterized by?
Central hypersomnias are characterized by excessive daytime sleepiness (EDS) and/or increased sleep (hypersomnia) not caused by disturbed nocturnal sleep or misaligned circadian rhythm.
WHAT IS cataplexy?
Cataplexy is a sudden and temporary loss of muscle tone or muscle weakness, typically triggered by strong emotions such as laughter, surprise, or excitement. It is a key symptom of narcolepsy, a neurological sleep disorder. Cataplexy occurs due to a lack of hypocretin (also known as orexin)
What treatments are effective for narcolepsy?
Effective treatments include lifestyle changes, antidepressants, stimulants, and sodium oxybate.
What treatments are effective for narcolepsy?
Effective treatments include lifestyle changes, antidepressants, stimulants, and sodium oxybate.
What is one reason why Restless Legs Syndrome (RLS) is under-diagnosed?
Lack of specific diagnostic markers and thresholds for symptom severity.
Which neurotransmitter is suggested to play a primary role in the pathophysiology of RLS?
Dopamine.
Approximately what percentage of adult RLS subjects present with Periodic Limb Movements in Sleep (PLMS)?
70% to 90%.
Name one neurological or psychiatric condition that is associated with higher rates of RLS.
Migraine, multiple sclerosis, spinal cord lesions, parkinsonism, and mood disorders.
What is a potential treatment option for chronic and clinically significant RLS?
Non-ergot dopamine agonists or a-2-d calcium channel ligands.
What is the prevalence of chronic fatigue in people seen in primary care?
Chronic fatigue is reported in more than 20% of people seen in primary care.
What are some examples of medical and neurological diseases in which chronic fatigue can be a part?
Chronic fatigue can be a part of medical and neurological diseases such as anaemia, multiple sclerosis, and poststroke.
What is the clinical definition of fatigue?
Fatigue is best defined as difficulty in initiation of or sustaining voluntary activities.
How can pathological fatigue be understood in neurological disorders?
Pathological fatigue is best understood as an amplified sense of normal (physiological) fatigue that can be induced by changes in one or more variables regulating work output.
What are some examples of fatigue being present in the disorders of the peripheral, autonomic, and central nervous system?
Fatigue is consistently seen with lesions in pathways associated with arousal and attention, reticular and limbic systems, and the basal ganglia.
How can peripheral fatigue be assessed clinically?
A distinctive topographic pattern of myopathic weakness is a strong clue for the peripheral origin of fatigue. Disorders of the neuromuscular junction are typical examples of muscle fatigability.
What is the Jolly test used for?
The Jolly test is a standard electrophysiological procedure for screening myasthenic disorders, involving repetitive electrical stimulation of selected motor nerves at low frequency (3 Hz).
What is Single Fiber Electromyography used for?
Single Fiber Electromyography is a special technique of recording single muscle fiber action potentials and is a sensitive test for neuromuscular junction transmission disorders.
What are some screening tests for mitochondrial myopathy?
Measurement of pre-exercise and postexercise oxygen saturation of venous blood during aerobic maximum forearm exercises can be used as screening tests for mitochondrial myopathy.
What is the typical exercise duration in the forearm ischaemic test for patients with disorders of glycogen metabolism?
Patients with disorders of glycogen metabolism are seldom able to exercise beyond 1 minute in the forearm ischaemic test.
