Disorders of consciousness
and sleep disorders
doc. MUDr. Valja Kellerová, DrSc.
Department of Neurology
Contents
• Brainstem reticular formation disorders
• Pathophysiology of coma
• Neurological examination of the comatose
patient
• Sleep disorders, classification
• Narcolepsy, cataplexy
• Hypersomnia, sleep apnoea syndrom
• Parasomnias
Brainstem reticular formation (RF)
• descending reticular
system
– inhibitory system in
medulla oblongata,
suppresses motion,
reflexes, muscle tone
– facilitatory system in
the whole brainstem,
facilitates movements,
exaggerates reflexes
• ascending reticular
activating system
Descending reticular system
• inhibitory
stimuli from:
– suppressor cortical regions
– basal ganglia
– anterior parts of cerebellum
disorder:
decerebrate rigidity
• facilitatory
stimuli from:
– vestibular nuclei
– proprioceptive stimuli
disorders:
cataplexy
sleep paralysis
Pathophysiology of decerebrate rigidity
Descending reticular system – inhibitory disorder: decerebrate rigidity
• in extensive midbrain lesion,
the inhibitory syst. in
medulla oblongata does not
obtain stimuli from the
upper parts and so
facilitatory system prevails:
• hypertonicity, opisthotonus,
clenched jaw, extension of
the arms and legs, internal
rotation of the arms
• obtained:
– tonic neck reflexes
– oculocephalic reflex
Mumenthaler 1990
Ascending reticular activating system
• activates the cortex, maintains alert
wakefulness
• clinical signs of a lesion:
– sleep disorders
o pathological sleepiness (lowered function)
o insomnia (irritation)
– disorders of consciousness
o coma (lowered function)
o generalized epileptic seizures (irritation)
Ascending reticular activating system
Visual stimuli
RF
Trigeminal stimuli
Auditory stimuli
Sensory stimuli
Pathophysiology of coma
A conscious state depends on intact:
• cerebral hemispheres
• the ascending reticular activating system in
the brain stem (midbrain, hypothalamus,
thalamus)
• interconnections between upper brain stem
and hemispheres (ascending projections from
the reticular formation toward the cerebral cortex)
Pathophysiology of coma
Impairment of conscious
level:
• diffuse hemisphere
damage
• brain stem involvement
• involvement of the long
tracts between the brain
stem and the cortex
(concussion, diffuse axonal
injury)
Lindsay
Impairment of conscious level – lesion
location (Lindsay et al., Neurology and neurosurgery illustrated, 1991):
diffuse hemisphere damage (not small focal lesions)
No
bilateral thalamic lesion
supratentorial mass s tra transtentorial herniation
infratentorial mass lesion brain stem compression
brain stem lesion
(involving reticular system)
or from tonsillar herniation
(indirectly)
Impairment of conscious level – brain stem lesion
involving reticular formation:
• in diencephalon (thalamus)
• in midbrain – tegmentum - alpha coma (rare)
nc.
- coma
(tr. corticospinalis
tr. corticobulbatis)
Alpha coma
Duffy F.H. 1989
Apallic syndrome (vegetative state):
• severe bilateral involvement of the cortex or
the subcortical white matter (decortication,
„a-pallium“ = „without cortex“)
• brainstem functions are preserved
• manifestations:
– coma vigile
– primitive reflexes – sucking, grasping and
oral automatisms are prominent
– focal findings (pyramidal), posture: flexed arms,
or global cerebral dysfunction
Coma vigile = syndrome (a part of the
apallic syndrome). Clinical findings:
• Disorder of consciousness: no perception, no
reaction to commands, no awareness of the
environment, no self-awareness
• wakeful appearance, with eyes open, arousal
• no purposeful or voluntary responses to stimuli
• sleep-wake cycles are preserved
• the patient lies passively without moving and
without speaking (akinetic mutism)
• after recovery – amnesia
• persistent vegetative state – persists for 1 month,
permanent – for 3 months (or 1 year, after trauma)
Examination of the comatose patient
•
Disorder of consciousness is
– a true medical emergency
– the diagnostic problem, the goal - to distinguish
the cause (structural, focal or diffuse - toxic or metabolic
– symmetrical)
•
The initial assessment:
– vital functions (respiration, circulation),
appearance…(the head – marks of trauma?...)
– history (trauma, previous illnesses, epilepsy, alcohol…)
– information about farmacological influences:
•
•
•
sedatives
analgetics (miosis)
muscle relaxants
Neurological examination of the comatose
patient
• assessment of the level of consciousness –GCS
• the topical diagnosis
• neurological examination:
– it is impossible to examine some signs which
require the patient´s cooperation
– in addition, it is necessary to examine some
reflexes which are present in coma only
– assessment of brainstem functions, motor function,
muscle tone, respiration
– assessment of focal findings
Examination of the comatose patient
The major neurologic functions to be observed:
•
•
•
•
•
•
level of consciousness
exam. of the eyes - pupils, ocular movements…
diencephalic and brainstem reflexes
other cranial nerves, reflexes, meningeal signs
respiration
motor function
Examination of the eyes
• palpebral fissures
– symmetry and size (nn. III, VII)
– eyelids – muscle tone (open eyes – pontine lesion or n.VII)
• pupils
– size: miosis – opiates? mydriasis – atropine? or
a brainstem lesion
– reactivity: the light reflex – absent – midbrain damage
(pupils are fixed to light)
– symmetry: anisocoria – unilateral unreactive mydriasis
- uncal transtentorial herniation
Pupillary abnormalities in brainstem lesions
(Plum F., Posner J.B., 1972)
miosis,
2mm
mydriasis,
6mm
1mm,
reactive
tegmental,
4-5mm
Examination of the eyes - ocular
movements
• position of the eyes at rest:
– dysconjugate horizontally - strabismus (III, IV, VI),
vertically - skew deviation
– conjugate deviation of the eyes
• ocular movements
– spontaneous (involuntary)
• slow roving eye movements (conjugate or
dysconjugate) – intact brainstem
• rare: ping-pong movements (fast), ocular dipping (slowfast), ocular bobbing (fast-slow), opsoclonus (fast, irregular)
– reflex eye movements (conjugated)
Diencephalic and brainstem reflexes
• Reflex eye movements (vestibular stimulation):
–the oculocephalic (or “doll´s head”)
reflexes (present only in coma)
• horizontal – rapid rotation of the head –
the eyes move in the opposite direction
(looking forward all the time)
absent – pontine lesion
• vertical – passive flexion or extension of the neck
– the oculovestibular (vestibuloocular or caloric)
reflex
The oculocephalic reflex (horizontal)
Hopkins
Diencephalic and brainstem reflexes Reflex eye movements:
– the oculovestibular or caloric reflex –
the ice-cold water, instilled into the external
auditory canal, causes tonic deviation
of the eyes toward the side of the stimulus
(in the comatose patient, with intact brainstem)
Other diencephalic and brainstem reflexes
• the ciliospinal reflex – pupillary dilatation
(1-2 mm) in response to a painful stimulus
absent – diencephalic lesion
• the frontoorbicular (glabellar, nasopalpebral)
reflex:
tapping between the eyes – blinking
absent – diencephalic or brainstem lesion
it habituates to repeated stimuli – disappears – cortex is intact
it does not habituate – persistent contaction or blepharospasmus in apallic syndrome
Other diencephalic and brainstem reflexes
• the oculo-cardiac reflex:
compression of eyeballs slows down
the heart rate
absent in medulla oblongata lesion
• the corneal reflex - absent in pontine lesion
• the masseter reflex - absent in pontine lesion
• the gag reflex - absent in medulla oblongata lesion
Respiration: abnormal respiratory patterns
Lesions:
(Plum F., Posner J.B., 1972)
cerebral
hemispheres
CheyneStokes
Central
neurogenic
midbrain
pons
pons
medulla
oblongata
Patterns:
(Plum F., Posner J.B., 1972)
apneusi
s
cluster
ataxic
Respiration
• Central respiratory disorders can have
localizing significance, but
• if the patient is hypoventilating, intubation
with assisted respiration should be considered
Motor function
• Assessment: (asymmetry – paresis)
– spontaneous movements
– posture
– muscle tone
– movements after a painful stimulus:
the supraorbital ridge
the nail bed
compression of
the sternum
Decorticate and decerebrate posture
• Decorticate posture (rigidity):
flexion and adduction of the arms,
(flexion of the wrists, fingers,)
extension (and plantar flexion)
of the legs
• Decerebrate posture (rigidity): extension, adduction
and internal rotation
of the arms,
extension of the legs
Netter
Other postures
• Mixed decerebrate rigidity - extension, adduction
and internal rotation of the arms,
hypotonia (or atonia) of the legs – lower pontine
lesion
• Generalized atonia – medulla oblongata lesion
Motor function disorders Plum F., Posner J.B., 1972
Lesions:
Motor
response:
unilateral,
hemisphere
hemispheres,
diencephalon
bilateral
abnormal
flexor
response
midbrain
abnormal
extensor
response
pons
mixed
response
Rostrocaudal (craniocaudal) deterioration
• is the progressive decline in neurological status
due to more caudal propagation of the lesion or
downward displacement of the brainstem
• consequence of central herniation
• cause: a supratentorial space occupying mass
(tumor, hemorrhage or edema)
• Important:
to recognize rostrocaudal
deterioration early in order to institute therapy
to prevent progression (against edema, operation,
decompressive craniectomy…)
Rostrocaudal deterioration
• Levels of deterioration:
– Cortical - subcortical
– Diencephalic
– Midbrain (often due to herniation of the uncus of the
medial temporal lobe)
– Pontine
– Medulla oblongata
The deterioration at the certain level of the brainstem is
accompanied by disorders of all higher levels.
Regression of the damage – reparation (repair) is
anterograde
Sleep – two states:
• Non-rapid eye movement (non-REM) sleep
(synchronous, slow wave sleep) – 4 stages:
– stage 1 – drowsiness (somnolence): in EEG alfa,
beta, theta waves
– stage 2 – light sleep: in EEG theta waves, sleep
spindles, K-complexes
– stage 3 – deep sleep: in EEG theta a delta
– stage 4 – deep sleep: in EEG delta
• Rapid eye movement (REM) sleep
(paradoxical): in EEG a low voltage record with
mixed frequencies, dominated by fast activity
Sleep cycles
• Duration about 80-120 minutes
• NREM sleep: 60-90 minutes
• REM sleep:
10-30 minutes (it prolongs
during night)
Sleep disorders - classification
• the classification is necessary to discriminate
between disorders
• the earliest classification systems were organized
according to major symptoms:
– insomnia
– excessive sleepiness
– abnormal events that occur during sleep
• the International Classification of Sleep Disorders
(2005) combines a symptomatic presentation (as insomnia)
with pathopysiology (as circadian rhythms) and body systems
(e.g. breathing disorders).
Sleep disorders
International Classification of Sleep Disorders
(ICSD version 2 – 2005):
• insomnias
• sleep related breathing disorders
• hypersomnias of central origin
• circadian rhythm sleep disorders
• parasomnias
• sleep related movement disorders
• isolated symptoms
• other
Sleep disorders – diagnostic procedures
• the sleep history
– the chief complaint – to explain, what is meant by
„insomnia“, „tiredness“, „sleepiness“
– the timing, duration, frequency, course
– a detailed sleep log (2-3 weeks):
•
•
•
•
•
•
•
the patient´s bedtimes
times of sleep onset
noctural awakenings
final awakenings
times of arising
the number of brief daytime naps (narcolepsy?)
snoring (obstructive sleep apnea?)….
– medication…
Sleep disorders – diagnostic procedures
• Scales, questionnaires
• Electroencephalography:
– polysomnography
– multiple sleep latency test (MSLT)
Epworth Sleepiness Scale (ESS)
• is a scale intended to measure daytime sleepiness
by use of a very short questionnaire
• it was introduced in 1991 by Dr Murray Johns of Epworth
Hospital in Melbourne, Australia
• is used to determine the level of daytime sleepiness
– a score of 10 or more is considered sleepy
– a score of 18 or more is very sleepy
• if you score 10 or more on this test, you should consider whether you
are obtaining adequate sleep, need to improve your sleep hygiene
and/or need to see a sleep specialist
Epworth Sleepiness Scale
Use the following scale to choose the most
appropriate number for each situation:
0 = would never doze or sleep, no chance of dozing
1 = slight chance of dozing or sleeping
2 = moderate chance of dozing or sleeping
3 = high chance of dozing or sleeping
Epworth Sleepiness Scale
Situation
Chance of Dozing or Sleeping
Sitting and reading
____
Watching TV
____
Sitting inactive in a public place
____
Being a passenger in a motor vehicle
for an hour or more
____
Lying down in the afternoon
____
Sitting and talking to someone
____
Sitting quietly after lunch (no alcohol)
____
Stopped for a few minutes in traffic
while driving
____
Total score (add the scores up)
____
Excessive daytime sleepiness, EDS
• An increase in total sleep time during the 24hr day (hypersomnia) or
• Attacks of unavoidable naps during the day,
drowsiness, lowered alertness
• Epworth Sleepiness Scale score >10
• MSLT
Excessive daytime sleepiness – causes:
• restriction of sleep - chronic sleep debt
(getting too little sleep, <7 hr)
• irregular sleep-wake schedules – shift
workers on rapidly rotating work schedules
• diseases:
– hypersomnias of central origin
– hypersomnias in poor night sleep (obstructive
sleep apnea, RLS, insomnia...)
– neurological diseases (Parkinson´s disease,
encephalitis, stroke, traumatic brain injury…)
– psychiatrical diseases (depression, anxiety…)
• medication
Central hypersomnia
• Narcolepsy with cataplexy, without cataplexy
• Recurrent hypersomnia (Kleine-Levin sy)
• Idiopathic hypersomnia
• Behaviorally induced insufficient sleep sy
• Hypersomnia associated with other disorders
(psychiatric – bipolar disorder…)
• Hypersomnia associated with use of drugs
and alcohol
Narcolepsy
• is characterized by abnormal REM sleep
regulation
• patients with narcolepsy have deficit of
hypocretin 1 (orexin) in the CSF and brain
• genetic predisposition – narcolepsy occurs in patients
with a specific HLA subtype -the HLA-DR2 (human
leucocyte antigens genotype DR2)
• the prevalence of narcolepsy is about 0.05-0.1%
• it usually begins between the ages of 15 and 35 years
Narcolepsy
• Monosymptomatic
• Polysymptomatic, characterized by:
– Sleep attacks
– Cataplexy
– Sleep paralysis
– Hypnagogic hallucinations
• Idiopathic, essential
• Symptomatic, secondary
Narcolepsy
• brief attacks of falling asleep (several minutes)
• their onset is irresistible, imperative
• they occur repeatedly, the circumstances may
be inappropriate for sleep (while standing,
walking, eating, active conversation…)
• the sleep attacks may begin with REM stage,
the patient falls into deep stages of sleep immediately
• falling asleep may be without drowsiness,
driving a car is prohibited
Cataplexy
• Sudden loss of postural tone, partial or
complete muscle weakness (sparing the
muscles of respiration)
• the patient is fully awake, but cannot move
• it is triggered by a strong emotion like
laughter, anger, surprise or excitement
• usually lasting up to 1 min
Cataplexy
Netter
sleep paralysis
•
•
•
•
•
a patient becomes transiently unable to move
before sleep onset or just after awakening
patients are fully awake
it lasts seconds to minutes
breathing is preserved
sleep paralysis
Netter
Hypnagogic halucinations
• vivid, frightening dreams, unpleasant
• visual, in color, auditory, tactile, often complex
• occur at the time of sleep onset or awakening
• Cataplexy, sleep paralysis and hypnagogic
hallucinations are dissociated fragments of
the REM state that intrude inappropriately on,
or persist into, wakefulness
Narcolepsy - the diagnosis
• multiple sleep latency test (MSLT):
– the whole day
– polysomnography is recorded at 2-hour intervals (20´)
– the patient is given 20 min to fall asleep (5 opportunities)
– the latency to sleep onset is measured
– sleep stages are assessed
• diagnosis of narcolepsy:
– short latency to sleep onset (less than 5-7 min)
– sleep onset REM periods (if 2 or more sleep periods
contain REM sleep, then a diagnosis of narcolepsy is highly likely)
Narcolepsy - therapy
• Naps of even brief duration are helpful
• Against the narcoleptic sleep attacks: stimulant
medication:
– Methylphenidate
– Modafinil
• Against cataplexy, sleep paralysis and hypnagogic
hallucinations: drugs which inhibit REM sleep:
– Tricyclic antidepressants, imipramine, clomipramine
– SSRI (selective serotonin reuptake inhibitors),
fluoxetine…
Recurrent (periodic) hypersomnia
• Recurrent episodes of sleepiness lasting 2 - 28
days, at least once a year
• At the beginning of the episode, sleep lasts 18hrs
and more
• Often superficial sleep stages with awakening
• Intermittent, transient, with weeks to months of
normal wakefulness between episodes of EDS
• Polysymptomatic form – sometimes with bulimia,
polydipsia, behavioral changes, hypersexuality
– Kleine-Levin syndrome - rare
Idiopathic hypersomnia
Excessive daytime sleepiness – permanent:
• The night sleep is lengthened, prolonged >10hrs
• Difficult to get up in the morning (lethargic form)
• Without prolonged night sleep (somnolent form)
• Polysomnography – normal sleep patterns
• sleep drunkenness – an inability to fully awaken
in the morning, with reduced cognitive and motor
abilities for about 30 min, with cerebellar signs
• Daily sleepiness is not so imperative
• Hypersomnia may be also secondary, symptomatic – the
lesion is in the floor of the 3rd ventricle
Sleep apnea syndrome, SAS
• Respiratory rate fluctuates during sleep with short
pauses
• apnea = break of breathing longer than 10 sec
• Causes:
– central (respiratory movements fail) – rare, causes:
lesion in medulla oblongata (infarction, tumour…) or
congenital disorder (loss of automatic breathing control)
– peripheral – obstructive – from mechanical obstruction
of the airway, respiratory movements are present, loud
snoring is frequent
– causes: obesity, large tongue, long soft palate, tonsillar
enlargement…
Sleep apnea syndrome (obstructive):
Netter
Sleep apnea syndrome (obstructive)
• After breathing ceases, hypercapnia and hypoxia
occur which stimulate respiration and awake the
patient
• Sleep is fragmented, leads to daytime sleepiness
• The end of apnea – sympathetic reaction with
tachycardia and arterial hypertension
• Consequences: sleep apnea syndrome is a risk
factor of pulmonary and systemic hypertension
and cardiac arrhythmia
Treatment of obstructive sleep apnea syndrome
• continuous positive airway pressure (CPAP)
during sleep, applied through the nose, by fitting a
mask to the nose, with air from a compressor
(positive pressure
of 5-10cm H2O)
• Mechanical airway obstruction should be relieved
by operation (uvulopalatopharyngoplasty…)
Parasomnias
• Events occurring in relation to sleep,
dissociations of sleep
• Episodic, abnormal
• States resembling prolonged sleep, from
which the patient can be aroused
• classification of parasomnias:
– Related to non-REM sleep
– Related to REM sleep
Non-REM-sleep-related parasomnias
• sleep drunkenness
• In idiopathic hypersomnia
• Desorientation, slowness, automatic
movements
• Cerebellar signs are present
• Lasts up to 30 min, amnesia
• EEG: sleep stages 1-2
Non-REM-sleep-related parasomnias
• somnambulism, sleep-walking
• Repeated episodes with automatic
movements or walking, eyes open, poor
coordination, injury !!!
• If awakened – disoriented, confused,
then amnesia
• Children aged between 4 and 12 years,
often familiar occurrence
Non-REM-sleep-related parasomnias
• pavor nocturnus, night terrors
• In stage III-IV of non-REM sleep
• Dramatic, sudden arousal, the child cries, with
eyes open, disoriented, mydriasis, tachycardia,
sweating
• amnesia, familiar
• enuresis nocturna, bed wetting
• Disorder od arousal
• therapy – training of micturition control
Non-REM-sleep-related parasomnias
• bruxism
• Rhythmic teeth grinding during sleep
• Damage of dental surfaces
• jactatio capitis nocturna
• Stereotypical rhythmic movements of the head or
entire body
• Infants at age 9 months
REM-sleep-related parasomnias
• nightmares
• dream–anxiety attacks
• Dreams with an unpleasant psychic
content, elicit awaking, often in children
• Patient remembers the content of the dream
•
sleep paralysis
• Awake, unable to move
• after awakening or before sleep onset
• it lasts seconds to minutes
• In narcolepsy
REM-sleep-related parasomnias
• hypnagogic hallucinations
• In narcolepsy
• REM behaviour disorder
• Always in REM phase, loss of muscle atonia !
• Accompanied by episodes of motor behaviour
• Violent behaviour, directed at the bed-partner or at
objects in the room, injury is often
• Vivid, unpleasant dreams, the content correspons
with the behaviour
• May be proved by polysomnography
•