EEG & Sleep😊

EEG & Sleep

EEG Waves (G BAT Dance)

Gamme (60) → Beta (24), Alpha (12), Theta (6), Delta (3)

As we move from Beta → Delta:

Amplitude increases
Brain activity decreases
Frequency decreases

Brain Waves & Sleep Stages

State	EEG (Electroencephalogram)	EMG (Electromyogram)	EOG (Electrooculogram)
Awake	Fast activity	Activity	Fast activity
NRM (N3)	Slow activity (delta waves)	Some activity	Slow activity
RM	Fast waves (saw-tooth)	Very less activity	Fast activity

State / Wave Type	EEG / Dominant Wave (Frequency & Amplitude)	Key Features	Associated Characteristics
Gamma Wave	Highest freq 30–80 (avg. 60), Lowest amplitude	Highly active brain	Focused attention (meditation, problem-solving)
Beta Wave	~24 Hz, Wave of attention or wakefulness Low amplitude β like EEG → in REM	Rapid Eye Movement High Muscle Activity Mnemonic: Our Beta → Awake, alert, eyes open.	Awake, alert, eyes open. Prefrontal Cortex
Awake, relaxed, eyes closed.	Alpha Wave: ~12 Hz Wave of inattention or relaxed state Medium amplitude	α block: Replacement of α wave with ß wave.	Occipital and Parietal Cortex
NREM Sleep	• Brain and physiological activity are lower than in the awake state. • Dreams are not remembered. • Penile erection is absent. • Body movements are present.	75-80% of total sleep time Smooth Eye Movement Low Muscle Activity	ㅤ
N1 (Light Sleep)	Alpha → Theta wave Theta: ~6 Hz, Medium-low amplitude ◦ Insomnia	Transition phase of sleep Theta waves also seen in memory	Hippocampus (Also seen in short term → Long term memory conversion)
N2	Sleep spindles ► Burst of waves (12 to 14 hertz). K complex Sharp negative waves followed by positive waves. ◦ Bruxism	Max time spent	Mnemonic: ◦ N → Enormous time (80%) ◦ NREM 2 → maximum time → Too (2) Enormous
N3 (Deep Sleep)	Delta Wave: ~3 Hz Lowest frequency (0.5 to 3 hertz) highest amplitude NREM disorders: ◦ Insomnia ◦ Night terror ◦ Somniloquy ◦ Nocturnal enuresis	Deep sleep (N3) Appears in stage 3, max activity in stage 4	Benzodiazepines
REM Sleep	• Physiological activity is increased (as if awake). • Exception: Muscle tone is in a state of paralysis. • Dreams are remembered. • Penile erection is present. • Body movements are absent • Pontogeniculoocular waves → Rapid eye movement REM disorders: 1. Sleep apnea 2. Narcolepsy 3. Nightmares Mare → reMember → REM 4. RM sleep behaviour disorder	- 20-25% of total sleep time - Rapid Eye Movement (like awake) - Shows beta and alpha activity (high frequency). Characteristic saw-tooth waves ◦ High frequency and low amplitude waves. Paradoxical sleep Silent EMG + Beta like EEG = Key for REM	RM sleep behaviour disorder. • Involves movement (punching, kicking). • Occurs because complete paralysis is absent. • May be seen in Lewy body disease

Most difficult to wake up from

NREM stage 3

Parasomnias

Disorders of partial arousal

Reduced REM Latency:

Depression

Nacrolepsy

Elderly:

Low REM, Low N3

Steps

G BAT Dance → order of decreasing frequency and ↑ amplitude

Thinnitt (theta) → N1

peaceful → slow ayiittt → low bp and pr,

Sleep → N2

Sleep spindle, k complex

Deep sleep (delta) → N3

night terror, somnambulism, bed wetting
don't remember dream

REM (RIM → erection, ↑ bp, pr)

nightmares → remember dreams

N2

REM SLEEP

REM Sleep – Hormonal Effects

Effect	Hormones
↑↑	Prolactin, LH, FSH
↓↓	GH, TSH, Cortisol

Mnemonic: REM → Story of Remi

Remi wanted to get periods (LH, FSH) and produce milk (Prolactin)
She did not want to grow (GH) or build muscles (Cortisol). She did not take thyroid medication (TSH)

Sleep Types:

Polysomnography (Sleep Study):

Records:

EoG (eye movement),

EMG (muscle activity),

EEG (brain waves),

SPO2,

ECG,

breathing.

Q. On performing polysomnography in a patient, the waves of EOG, EEG, and EMG, from above
downwards, are seen below. Which stage of sleep do the marked areas represent?
EOG: Electrooculography
EEG: Electroencephalography
EMG: Electromyography

A. REM sleep
B. NREM I sleep
C. NREM II sleep
D. NREM II sleep

ANS

REM sleep

Q. What does the given image represent?

A. Hypnogram
B. Electroencephalogram
C. Polysomnogram
D. Epworth sleep assessment

ANS

Hypnogram

EMG Findings

Wake State

At wake state, the muscles have a particular tone due to spontaneous electrical activity.

Sleep

As we sleep, the tone of the muscles is reduced and lowest in a state of deep sleep.

EOG Findings

Wake State

At wake state, the waves are coarse.

Sleep

As we fall asleep, the waves become finer with bigger amplitude.

Sleep Disorders

Somnambulism (Sleepwalking):

Person engages in motor behaviors while unconscious.

Activities can be complex (walking, opening fridge, eating).

Difficult to awaken;

may be confused or attack.

Better to guide them back to bed.

Usually remits in adolescence and adulthood.

Treatment if it persists: benzodiazepines.

Sleep terrors or Night terrors:

Sudden arousal with fearfulness (scream, cry, panic).

Appears confused if awakened.

Person cannot recall the dream (NREM disorder).

Bruxism (Teeth grinding):

Grinding of teeth in sleep (an NREM disorder).

May make loud sounds.

Can damage enamel;

teeth gaps are used for protection.

Somniloquy (Sleeptalking):

Person talks during sleep.

Does not remember talking upon waking.

Involves movement (talking), so it is an NREM disorder.

Nightmare disorder:

Sudden arousal with fear from a bad dream.

The person is able to recall the dream.

Narcolepsy:

Cause:

Deficiency of hypocretin (also called orexin).

OR defective hypocretin receptors
Deficient in the lateral hypothalamus.
Mnemonic: Orexin → onarnnirikkan

Cause decreased REM sleep latency

Has a tetrad of symptoms:

Sleep attacks:

Excessive daytime sleepiness

(most common symptom).

Cataplexy:

Sudden loss of muscle tone.

Triggered by emotional outburst (e.g., laughter).

Not catalepsy.

Holding odd posture for long (passive)

Sleep paralysis:

Person wakes up

but cannot move.

Special hallucinations:

Hypnogogic: When going to sleep.

Hypnopompic: When coming out of sleep.

Treatment:

Regimen of forced naps.

Drugs: Modafinil (first-line).

CNS stimulant.
Alpha 1 agonist.
FDA approved for narcolepsy.

Kleine-Levin Syndrome:

Episodes of hypersomnia.

Hyperphagia (eats a lot).

Hypersexuality.

May show disinhibited behavior (e.g., aggression).

Patient is asymptomatic between episodes.

HORMONAL CHANGES

Growth hormone

↑ in N3 of NREM sleep.

Prolactin

↑ in REM sleep.

Luteinizing hormone: Nocturnal LH surge in puberty.

Melatonin: Sleep-inducing hormone secreted by pineal gland.

PHYSIOLOGICAL CHANGES

Muscle atonia → Prevents acting out dreams.

Exceptions:

Diaphragm: For respiration.
Extra ocular muscles: For eyeball movement.

Genital organ enlargement (Penis/clitoris).

SLEEP Disorders

Narcolepsy

Modafinil (Drug of Choice)

Insomnia (Drug of Choice)

BZD: Clonazepam > Alprazolam

For patients with history of drug abuse/elderly:

Dual Orexin Receptor Antagonists (DORA)

MOA: Inhibits wakefulness

Blocks Orexin-1 (OX1) and Orexin-2 (OX2) receptors
Orexin neurons located in lateral hypothalamus
Active during wakefulness

Drugs:

Suvorexant
Daridorexant

These promote sleep induction & maintenance
Mnemonic: Night urangan DORA () Save (Suvo) Dari () Story

For other patients:

Z drugs → act on α1 of GABA

Zolpidem
Zaleplon (shortest → sale)
Zopiclone (longest → shopping)
These promote sleep induction & maintenance

Ramelteon (Melatonin Agonist)

For sleep induction only
Ramettan → urakkum

For blind patients with night insomnia

Circadian rhythm disorder

known as Non 24hr sleep wake rhythm disorder

DOC: Tasimelteon
Taxi for blind to sleep

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