Sleep and Pathology Overview - Lecture 7

Lecture 7 - Sleep and Pathology: Overview

• Sleep basics
• Sleep disorders
• PTSD
• Depression and insomnia
• Sleep staging

Sleep Staging

• Assessing sleep architecture is crucial for identifying abnormal sleep patterns
• Hypnograms are created by dividing sleep recordings into 30-second epochs
• Sleep stages are assigned to each epoch through visual inspection

Sleep Stages - Example (N3)

• EOG (Electrooculogram): Measures eye movements
  • Data from frontal, central, and occipital electrodes are displayed.
• EMG (Electromyogram): Records muscle activity
  • Data displayed (REM and non-REM)
• EEG (Electroencephalogram): Measures brain waves
  • Data displayed from frontal, central, and occipital electrodes.

Age-Related Changes in Sleep Patterns

• Total sleep time decreases with age
• Wakefulness increases,
• Reduced slow-wave sleep (SWS) and REM sleep
• Sleep becomes more fragmented throughout the lifespan

Memory Consolidation

• Sleep plays a role in the reactivation of newly encoded information
• Information is transformed into long-lasting memories
• Sleep rhythms are involved

Circadian Rhythms

• Our body's internal clock
• Clock genes are found in various organs and tissues

Sleep Regulation

• Sleep is regulated by rhythmic processes
• Circadian rhythms regulate the internal sleep clock
• Sleep pressure interacts with circadian rhythms

Sleep Disorders: Categories and Prevalence

• Insomnia: 10% of the population, increases with age
• Sleep-disordered breathing: 1 billion globally, increases with age
• Central disorders of hypersomnolence: 0.15% of population
• Circadian rhythm sleep-wake disruption: up to 44 per 100,000 people
• Parasomnia: up to 40% of population
• Sleep-related movement disorders - up to 40 per 100,000.
• Non-organic sleep disorders
• Difficulties falling asleep, staying asleep, or early-morning awakenings.

Sleep Disorders: Specifics

• Sleepwalking (somnambulism): Altered consciousness, reduced consciousness, reduced reactivity and dexterity; no memory of sleepwalking after waking.
• Night terrors (pavor nocturnus): episodes of extreme fear, panic, often violent movements, and autonomic arousal; no memory of events after waking up.
• Nightmares/anxiety dreams: vivid dream experiences, intense fear; themes such as threats to safety, often recur.

Organic Diseases/Substances

• Chronic kidney, gastrointestinal disease
• Chronic pain
• Epilepsy
• Heart and lung disease
• Headaches
• Stroke
• Multiple sclerosis
• Alcohol, antibiotics, anti-dementia drugs, blood pressure medications, hormone supplements

Hypersomnia (Sleep Apnea)

• Symptoms: snoring, pauses in breathing, headaches, non-restorative sleep, daytime tiredness
• Prevalence: 2-4% of population, increases to 10-20% with higher age
• Risk Factors: obesity, males
• Treatment: Weight loss, CPAP, other medications as prescribed

Comorbidity of Sleep Disorders

• 20-40% of psychiatric patients experience sleep problems
• Sleep problems can be risk factors for mental disorders like PTSD, or symptoms of mental disorders.
• Sleep is essential in the treatment of mental disorders.

Emotional Memory

• Memories composed of memory and affective tone
• Sleep consolidates declarative information from emotional content, including but not limited to memories and details of a story or event.
• Sleep consolidates emotional memories, while reducing their affective impact

Emotional Regulation

• REM sleep consolidates emotional memories, mediating their impact
• Sleep over time reduces the affective element of emotional memories, so emotions attached fade.

Sleep and PTSD

• Sleep disturbances are risk factors in PTSD development
• Sleep can lead to development of PTSD but sleep can be a protective factor or a resilience strategy.

Behavioral PTSD Therapy & Sleep

• Imagery rescripting is a therapy to modify aversive memories through integration of novel and adaptive information during sleep.
• Sleep may amplify changes in physiological distress from imagery rescripting.
• Intrusive thoughts, often related to PTSD, can be exacerbated by sleep disturbances.

Memory Suppression

• Suppressing memories is useful, suppressing memories of the past leads to weakened memories.

Sleep Deprivation

• Affects sleep-related cognitive processes, including memory
• Mood disturbances and impaired cognitive functioning can occur.
• Results in more intrusions after sleep deprivation

Depression

• Depressive disorders often involve a depressed mood and loss of interest for long periods.
• Prevalence: 3-5% of population; more common in women.
• Symptoms: poor concentration, excessive guilt, low self-worth, disrupted sleep, thoughts about dying or suicide, tiredness, or low energy
• Sleep is impacted by and impacts the severity of depressive disorders.

REM and Depression

• REM sleep alterations may be a biomarker for depression
• However, findings are confounded by age and sex, also other mental disorders display REM alterations
• Early REM onset and reduced SWS are symptoms of mood disorders.

Circadian Disruption

• Circadian rhythms can be phase-advanced in individuals
• A 6-hour delay in circadian rhythm may result in earlier REM onset, or affect the duration of REM sleep.
• Sleep deprivation, which acts anti-depressive by counteracting the S-process in the body, may be beneficial for those affected by mood disorders.

Insomnia

• Prevalence: 10% of the population, increases with age and is more prevalent in women
• Health risks: heart attacks, high blood pressure, obesity, substance addiction, anxiety, or suicidal ideology or trend

Insomnia & Depression

• Bi-directional relationship between insomnia and depression
• Insomnia increases risks for depression.
• Treatment of insomnia is essential component in treatment of comorbid mental disorders.

Insomnia Treatment

• Cognitive Behavioral Therapy for Insomnia (CBT-I) is a common treatment
• Restructuring thoughts, feelings, and behaviors to alleviate risk factors for and symptoms of insomnia.
• Treatment is effective in insomnia patients and results persist over time.

CBT-I in PTSD and Depression

• CBT-I is effective for PTSD and depression.
• Significant effects on sleep latency, wakefulness, sleep efficiency, and related symptoms.
• Large effects on insomnia, depressive symptoms, and sleep-related symptoms

Other Sleep-Related Techniques

• Breathing techniques, meditation, guided imagery
• Cognitive techniques to mitigate concerns about problems falling asleep
• Establishing routines and improving sleep hygiene can be beneficial.