Psych - Sleep Flashcards
Neurotransmitters of WAKEFULNESS
GLUTAMATE - most important
DA, NE, Histamine (anti-histamines make us drowsy), ACh
Neurons in brainstem reticular formation are in charge of cortical activation and keeping us awake. They project from the RF to the cortex (via the ascending reticular system) which has two pathways – dorsal (through thalamus) and ventral (extrathalamic)
Neurotransmitters of SLEEP
GABA!!!!!!!
Serotonin
Adenosine
GABA inhibits the brainstem, hypothalamus and RF – thalamocortical systems then get hyper polarized
Also a shift from sympathetic to parasympathetic
EEG –> low frequency high amplitude –> theta waves, SPINDLES and K complexes, delta waves
NON-REM sleep (no dreams)
Associated with REDUCED NEURONAL ACTIVITY
Composed of:
superficial or light sleep (stages 1 and 2) –> 50% of the night!
Deep or slow wave sleep (stage three - 20-25% of the night)
REM SLEEP (dreams)
REM is often known as PARADOXICAL sleep (EEG is same as awake! High frequency!)
Metabolic and physiologic activity of the brain INCREASES; DREAMS!!!
REM sleep –> increased ACh release (an awake NT!!!!) –> 20-25% of the night
Sleep and age
Kids get a lot of stage 3 (deep) sleep
As we age we get less and less deep sleep
Two phases REM/NONREM cycle every 90-120 minutes
We should be in REM sleep at 90 minutes
REM usually lasts 10-20 minutes, amount gets longer and longer with each cycle
Need about 7-9 hours on avg
Respiration
In NREM sleep, the brain is inactive and the respiratory drive is thus decreased – additionally, sensitivity at chemo receptors decreases
As we drift between stages 1 and 2, brain activity and thus respiratory drive fluctuates, leading to periodic breathing/short periods of apnea – Cheyne-Strokes Respiration –> this is normal
Overall, the respiratory drive during NREM IS STABLE, but LESS than wakefulness
Compared to being awake, during NREM there is:
1-2 L/min reduction in minute ventilation
2-8 mmHg PaCO2 increase
5-10 mmHg paO2 decrease
This is all NORMAL, but breathing problems (COPD, Asthma) these changes may be too much
Muscle tone and sleep
During REM sleep there is INHIBITION OF MUSCLE TONE (hypotonia) –> why we don’t act out our dreams!
This includes INTERCOSTAL and ACCESSORY MUSCLE ACTIVITY
ONLY the diaphragm is spared, but since it is working alone, the breathing is depressed
In BOTH NREM and REM, the muscles of the UPPER AIRWAY are influenced, increasing upper airway resistance (REM > NREM > Awake) –> important for APNEA
Insomnia overview
Unsatisfactory Sleep
10-50% of adults
Around 50% suffer from 1 symptom, 10 from severe/chronic insomnia which interferes with daily life
Have difficulty falling asleep, maintaining sleep, or complain that sleep is poor quality
Can be transient/acute (few days to weeks), subacute (up to 3 months) or chronic (more than 3 months)
Risk factors – female, single, pain/illness, depression/anxiety and any number of stressors
Treating acute = treating the stressor; but acute can become chronic if untreated
Primary Insomnia
Idiopathic
or Paradoxical - patients think they are, but are actually sleeping well
or Psychophysiologic (90%) –> most common type; can be acute or chronic; person gets stressed and sleeps poorly for a few nights, then they get all paranoid, trying to sleep well, but bad habits are hard to break; if they sleep well at other places, then this is the diagnosis
Secondary Insomnia
Can also be caused by:
Sleep disorders
Circadian factors
Environmental causes (loud environment)
Psychiatric/Psychological –> 40% of insomniacs have a diagnosable psych disorder! Can also be an early symptom of another psych disorder
Medical Reasons – this is the third leading cause of insomnia!! Includes a lot of diseases (pain, fibromyalgia, asthma, COPD, neuro disorders, etc etc)
Drug related –> caffeine, alcohol, decongestants, hypnotic-dependent insomnia, BP meds, birth control, SSRIs; abrupt stoppage of a sleep med
Inadequate sleep/hygiene –> bad habits, too much coffee, irregular sleep routine, lack of exercise or exercise just before bed, etc.
EPWORTH SLEEPINESS SCALE (ESS)
Most patients who see a sleep specialists complain about excessive daytime sleepiness
Most of the time, insufficient sleep or apnea is o blame
We can evaluate with the EPWORTH SLEEPINESS SCALE
Patients evaluate whether or not certain situations make them sleepy or not
8 categories are scored from 0-3, and a score LESS THAN 10 is NORMAL
Obstructive Sleep Apnea
Defined as an upper airway obstruction which can stop breathing, leading to arousals and oxygen de-saturation
Affects 2% of women and 4% of men
Most patients are 30-60 years of age
Hypopnea index how many times per hour patient stops breathing = 5+
ventilation is depressed normally! So apnea is a problem!
Apnea is associated with SLEEPINESS, SNORING, AROUSALS, and more serious conditions (arrhythmias, uncontrolled HTN, stroke, MI, DEATH!!!)
Risk factors – obesity, crowded oropharynx, collar size > 17 inches in guys, hypothyroid, weird shaped jaws
Apnea and Hypopnea
Apnea is defined as the ABSENCE of airflow at the nose and mouth for 10 seconds or longer
Hypopnea is a REDUCTION in airflow by 30% from baseline for 10 seconds or longer, with a 4% or greater drop in O2 saturation from baseline
Gold Standard for diagnosing Apnea?
POLYSOMNOGRAM
Records ECG, EMG, EEG, O2 sat, airflow, body position, effort
Categories of Apneas
CENTRAL - no effort is taken to breathe, meaning something is wrong up in the brain; and can be caused by heart failure or stroke
Obstructive - patient is trying to breathe, but airways are not cleared; you can see paradoxical movement between the chest and abdomen
Mixed - starts as central and ends as obstructive
