MC Qs 2 Flashcards
Triad of findings in tuberous sclerosis
- Intellectual disability (MR)
- Seizures
- cortical tubers on MRI
- subependymal nodules/giant cell astrocytomas - Dermatologic findings
- ash leaf spots (hypomelanotic macules)
- Shagreen’s patch = elevated hardened skin patch usually on lower back
- angiofibromas in butterfly pattern on face
Other: renal, eye, lung findings
Differentiate classic from common migraine
Classic migraine = w/ aura
Common migraine = w/o aura
Name features of these specific types of migraines
(a) Basilar migraines
(b) Opthalmoplegic migraines
(a) Basilar migraine = symptoms referable to the basilar artery: visual disturbance, vertigo, confusion, brainstem dysfunction
(b) Opthalmoplegic migraines = associated w/ retroorbital pain or CN nerve palsies of CN 3,4,6
2 tests to help confirm Dx of myasthenia gravis
- Tensilon test = edrophonium = readily reversible AChE inhibitor that improves muscle weakness (by decreasing ACh breakdown)
- Ice pack test- putting ice pack on pt’s forehead for several minutes temporarily relieves ptosis
60 yo M develops asymmetric distal muscle weakness
- modestly elevated CK
- wheelchair bound after 7 yrs of gradual progression
Dx
Dx = inclusion body myositis
-over 50 yo, distal asymmetric inflammatory myopathy (see inflammatory infiltrate on biopsy)
No tx :-(
Distinguishing features of PSP vs. Parkinsons
PSP: restricted vertical gaze, prominent falls
Name 2 other types of chorea that are not Huntington’s
Chorea gravidarum- in women of child-bearing age get a pregnancy test!
Sydenham’s chorea in children w/ rheumatic fever (check group A strep titer)
Triggers for
(a) Absence seizures
(b) Juvenile myoclonic epilepsy seizures
Triggers
(a) Hyperventilation can reliably reproduce absence seizures
(b) Juvenile myoclonic epilepsy seizures can be triggered by sleep deprivation, classically a teenager who p/w seizure after pulling an all nighter
Pt w/ known brain tumor experiences shaking of right hand that progresses up to r. arm and shoulder that continuous until LOC and tonic-clonic mov’t of entire body
Type of seizure?
Secondary generalized seizure
Generalized b/c entire brain involved
Secondary b/c initially it’s focal, than spreads
(a) What is epilepsia partialis continua?
(b) Body parts most commonly involved
(c) Possible complication
(a) Epilepsia partialis continua = persistent focal motor seizure (repetitive focal myoclonus or Jacksonian march) that recur every few seconds to minutes for days to years
(b) Often hand, foot, or face
(c) Possibe complicated by Todd’s phenomenon where involved body part afterwards has transient weakness (conceptually due to exhaustion of motor cortex)
Differentiate chorea from athetosis
Chorea- irregular, asymmetric random and continuous movements
Athetosis- slow twisting/writhing movements, typically distal muscles
Differentiate ballism from chorea
Ballism is an extreme form of chorea, where there is involuntary, violent flailing of extremities
Chorea = irregular, asymmetric random and continuous movements
Before diagnosing pt w/ idiopathic carpel tunnel, what should be ruled out?
R/o pregnancy and endocrinopathies (diabetes, thyroid hormone irregularities)
Mov’t d/o in pt who survived CO poisoning
Parkinsonism
76 yo M started a new medication 2 mo ago, p/w muscle aches/pains and slightly elevated CK
What med?
Atorvastatin
Statins (esp high doses) are a very common cause of myopathies
Guillain-Barre
(a) Mechanism
(b) Clinical features
(c) Timeline
Guillain-Barre
(a) Autoimmune, often following GI illness (campylobacter jejuni classically)
(b) Ascending paralysis, minimal sensory findings, areflexia
- loss of reflexes is key to clinical dx
- back pain 2/2 inflammation of nerve roots
(c) Hours to days
Name 2 trinucleotide repeat diseases
- Huntington’s
2. Fragile X = most common inherited cause of ID, most commonly known single-gene of autism
Name 2 other features of Juvenile Gout (Lesch-Nyan)
Lesch-Nyan
- hyperuricemia => gout and kidney stones
- neurologic dysfunction
- cognitive and behavioral disturbances, most notably self mutilating behavior (biting lip and fingers, like even biting fingers off EW)
Differentiate myoclonus and dystonia
Myoclonus = very rapid, brief, uncontrollable jerks
Dystonia = sustained, abnormal posture caused by simultaneous activation of both agonist and antagonist muscles
Lennox-Gastaut Syndrome
(a) Age
(b) Difference btwn West syndrome
Lennox Gastaut Syndrome
(a) Btwn 2-6 yoa
(b) Many parallels, but L-G typically multiple types (not just infantile spasms) and more frequent (like can have multiple a day
- EEG findings: slow wave forms btwn seizures, not hypsarrhythmia like West syndrome
- L-G more resistant to tx
Main features of NF1
Tumors along the nervous system:
- Neurofibromas = benign skin tumors, peripheral neurofibromas causing painful neuropathies
- plexiform neurofibromas = large benign tumor of nerves
- Lisch nodules = brownish-red spots in the colored part of the eye
- cafe au lait spots, axillary freckling
- seizures, MR**
- thinning of long bones
Overall: seizures, cafe au lait spots, neurofibromas, plexiform neurofibromas
-often presents w/ seizures before age 5
Migraines
(a) Duration
(b) Dx criteria
Migraines
(a) 4-72 hrs duration
(b) 2/4:
-unilateral
-pulsatile quality
-inhibition of daily activity
-aggravated by physical activity
1/2:
-photo/phono-phobia
-nausea/vom
21 yo M wakes up in the night w/ stabbing pain behind eye, episodes last 30-60 mins during which eye looks is red/swollen w/ ptosis and unequal pupil size
Dx
Dx = cluster headaches
= severe unilateral pain (orbital, supraorbital, and/or temporal) lasting 15-80 minutes associated w/ eye, nose findings
- ptosis, miosis, red conjunctivae, lacrimation, eyelid edema
- nasal congestion/rhionrrhea
- forehead and facial sweating
Differentiate simple vs. complex febrile seizures
Simple febrile seizure = GTC lasting less than 60 seconds w/ no recurrence w/in the next 24 hrs
-these don’t need tx
Complex febrile seizure = focal features lasting longer than 15 minutes or recurrence in 24 hrs
-these need tx
5 yo child w/ severe decline in ability to comprehend and produce speech
(a) Dx
(b) EEG finding
(a) Landau-Kleffner syndrome = infantile acquired aphasia = acquired epileptic aphasia
= aphasia (inability to understand or express speech) w/ abnormal EEG
(b) EEG: b/l spike and wave discharges (epileptiform activity) during non-REM sleep
- basically a kid 3-7 yoa who develops speech normally but then loses it and also has epileptiform activity during non-REM sleep
- development of aphasia in child who otherwise developed normally
What lab value must be monitored in pts taking oxcarbazepine/carbamazepine
BMP- monitor Na+ values b/c they are associated w/ hyponatremia
Pt w/ b/l, asynchronous ballistic mov’t of arms and legs
-pt is conscious during the events that last 30-120 seconds
Dx
Dx = non-epleptic seizures = pseudoseizures
Differentiating factor = not stereotypic (like true epileptic seizures)- last different amounts of time, differ in time and clinical presentation
65 yo being treated for Parkinson’s develops paranoia and hallucinations
Mgmt
First step = reduce Sinemet (carbadopa-Levadopa) dose
But if his Parkinsonian symptoms worsen, then can restart Sinemet while adding antipsychotic
-best choice of antipscyhotic = Quetiapine (seroquel)
Similarities btwn Rett’s syndrome and autosim
Lack of social reciprocity, young age of onset, loss of speech
-but Rett’s has known molecular etiology
Define akathisia
‘Motor restlessness’
subjective sense of inner restless in which pt feels compelled to move continuously
Differentiate movement d/o from extrapyramidal d/o
Synonymous, b/c movement d/o don’t affect the pyramids (spare the corticospinal tract), they are disorders of the basal ganglia
What is the most common primary CNS tumor in children?
(a) What kind of tumor is this?
(b) Clinical presentation
Medulloblastoma
a) PNET = primary neuroectodermal tumor
(b) Presents w/ cerebellar features: ataxia, signs of increased ICP (HA, vom
75 yo w/ trouble initiating gait, but once he gets started his steps become faster until he has trouble stopping
(a) Name this gait
(b) Associated d/o
(a) Festinating gait
2/2 postural instability from loss of dopaminergic signals
(b) Idiopathic Parkinson’s
Duchenne’s muscular dystrophy
(a) Pattern of inheritance
(b) Mutated gene
(c) Clinical presentation
(d) Associated findings
Duchenne’s muscular dystrophy
(a) X-linked recessive- hence why only boys get it
(b) Mutated dystrophin gene- encodes for protein that connects muscle fiber’s cytoskeleton w/ the extracellular matrix to allow for contraction/relaxation
(c) Presents in boys around 3-5 w/ trouble walking, rising from sitting (Gower’s sign), unable to ambulate by teenage and death by 20s
(d) Dilated cardiomyopathy
2 yo girl seemed healthy until 11 mo when she seemed floppy, continued to develop but lost skills around age 2 particularly in her hands
Dx
Dx = Rett’s syndrome
- only in girls, starts around 1-4 yoa w/ cognitive and physical deficits/decline
- normal early development followed by stagnation and eventual regression
- grey matter disease
Define status epilepticus
Status epilepticus = life-threatening condition of seizures lasting more than 5-10 minutes, or recurrent seizures w/o regain of consciousness in between lasting 30 minutes
Name two examples of primary generalized seizures
Absence seizures, tonic-clonic seizures
7 yo boy w/ day-dreaming spells numerous times during the day
-child has no recollection of these events, his grades start to suffer
Dx
Dx = absence seizures
Distinguishing features of MSA-Parkinson’s type over Idiopathic Parkinson’s
MSA-Parkinson’s type: b/l onset of symptoms, lack of tremor, prominent orthostatic hypotension
Recall: hot cross buns sign on neuroimaging
Pt w/ known brain tumor experiences shaking of right hand that progresses up to right arm and shoulder before terminating.
-no LOC
Type of seizure?
Simple partial seizure
Simple b/c no LOC
Partial bc specific definitive (not entire) part of brain involved
Most common reason why pts discontinue Depakote
Wt gain
3 most common brain mets that bleed
Bleeding brain mets: melanoma, renal cell, choriocarcinoma
Differentiate the 4 kinds of seizures
Simple partial seizures = one definitive area of the brain (partial) involved, no LOC (simple)
Complex partial seizure = one definitive area of the brain involved (partial), some alteration in consciousness (complex)
Primarily generalized = entire brain affected at once, loss of consciousness
Secondarily generalized (Jacksonian march) when single area of brain affected initially, then spreads to include the rest
2 mo w/ colic pain causing baby to bend over in pain, 3 hypopigmented lesions on skin that are more apparent w/ UV light
Suspected diagnosis?
Tuberous sclerosis = aut dom inherited neurocutaneous d/o characterized by tons of benign tumors of the head (cortical tubers), kidneys, skin
- Hypopigmented macules = ash-leaf macules
- GERD is common
Cornerstones of tx for myasthenia gravis
- maintenance w/ pyridostigmine = cholinesterase inhibitor
- steroids
- immunosuppressants (ex: azathioprine)
Last resort: IVIG, plasmaphoresis
-ppx thymus removal
10 yo w/ seizures characterized by laughing fits
(a) What type of seizure is this?
(b) Most likely due to neoplasm at what location?
(a) Gelastic seizures = sudden burst of energy (usually laughing or crying)
(b) Many causes, but most likely 2/2 hypothalamic neoplasm
3 MC mets to the brain
Lung, lung, lung, lung…
then breast and melanoma
Compare and contrast acute disseminated encephalomyelitis and multiple sclerosis
Both ADEM and MS are autoimmune demyelinating d/o
-similar MRI findings w/ multiple periventricular lesions
ADEM- acute onset, usually uniphasic, often in children following viral infection or atypical vaccination, p/w seizure, encephalopathy
MS- adult, recurring/remitting, no fever, more asymmetric unilateral findings not seizure/encephalopathy
Triad of NF2
Multiple schwannomas (usually b/l vestibular schwannomas), meningiomas, and ependymomas
Ependyma = epithelial lining of the ventricles, can be intra-axial or in the spinal cord
Tx for carpel tunnel
(a) First line
(b) Refractory disease
Carpel tunnel syndrome
(a) Conservative therapy: night brace/splint, avoidance of repetitive movements
(b) Release of transverse carpal ligament
Name one factor that differentiate tics from other movement disorders
Tics are considered semi-voluntary, in that w/ great effort they can be temporarily suppressed
Most focal epilepsies arise from which location?
Mesial temporal areas/hippocampus
Differentiate presentation of NF1 vs. NF2
(a) Which is more common?
NF2 presents before 20 usually from symptoms of CNS (benign) tumor compression of cranial nerves
ex: hearing loss from b/l vestibular schwannomas
NF1 presents before 5 yoa w/ seizures, painful neuropathies from peripheral neurofibromas, cafe au lait spots
(a) NF1 much more common than NF2
Why is lorazepam preferred over pheyntoin for acute seizure eradication?
Lorazepam has very rapid onset
Can’t give IV phenytoin too quickly 2/2 risk of cardiac arrhythmia
Infxn w/ what commonly precedes Guillain-Barre
Campylobacter jejuni = infectious febrile diarrheal illness
Which child w/ febrile seizures has higher risk of developing seizures as an adult
(a) Seizures lasting 5 or 30 minutes?
(b) W/ or w/o strong FHx of febrile seizure
(c) Focal vs. generalized features
HIgher risk of developing seizures as an adult if
(a) Seizure lasts longer than 15 minutes
(b) W/o strong Fhx
- so having strong family h/o febrile seizures doesnt increase risk
(c) Focal features
- generalized seizures is not a RF for seizures as adult
Buzzword: 2 yo w/ self-mutilating behavior
Dx
Dx = Lesch-Nyan disease
-X linked mutation in enzyme HGPRT => build up of uric acid
3 features
- neurologic dysfxn
- cognitive and behavioral disturbances, most notably self-mutilating behaviors (chewing lip/fingers)
- hyperuricemia => gout and kidney stones
Juvenile myoclonic epilepsy
(a) Typical presentation
(b) Tx
Juvenile myoclonic epilepsy = idiopathic generalized epilepsy
(a) 12-18 yo w/ brief episodes of involuntary muscle twitching early in the morning
- myoclonic jerks, typically upon wakening
(b) Valproic acid (depakote)
- seizures do not remit, tx is needed
- Keppra also a good first choice
Electrical stimulation of which cranial nerve is used to help control epilepsy?
Vagus nerve
-direct electrical excitation of the vagus can suppress the onset of seizures
Pt suffers completely lacerated median nerve. What would an EMG 3 months later show?
Fibrillations and positive sharp waves = finding of spontaneous depolarization of individual muscle fibers
-while normally innervated muscles are responsive as an entire motor unit (not individual fibers)
=> fibrillations and positive sharp waves indicate acute (weeks to 12 mo) motor axonal injury
Anti-epileptic most strongly associated w/ neural tube defects when given to pregnant women
Depakote
Distinguishing factor btwn absence seizures and complex partial seizures
No post-ictal state w/ absence seizures
Good test for absence seizures
Hyperventilation is a very reliable way of bringing out absence seizures
34 yo M p/w 3 mo of irritability and personality changes, enlarged liver and coarse tremor of UE. Mov’ts are slow and he is dysarthric
(a) Dx
(b) Additional expect physical exam finding
(a) Dx = Wilson’s disease = hepatolenticular degeneration
- lenticular nucleus = caudate and putamen
(b) Kaiser-Fleischer rings around the cornea 2/2 copper deposition
Pseudotumor cerebri
(a) Physiology
(b) RF
(c) Confirm dx
Pseudotumor cerebri
(a) Impaired CSF absorption
(b) Typically young obese F
- endocrine d/o
(c) Confirm dx w/ LP showing elevated opening pressure
Manifestations of Von-Hippel-Lindau disease
Autosomal dominant 2/2 mutation in VHL tumor suppressor gene => multiple hemangioblastomas (mostly of the eye and brain)
-also pheos, renal cell carcinomas, pancreatic cysts
See angiomas in the eye, brain imaging shows hemangiomas (not symptomatic unless ruptured), pheo/RCC/pancreatic cyst in family members
(a) What is the most common epilepsy syndrome in children?
(b) Prognosis
(a) Benign rolandic epilepsy = epilepsy w/ centrotemporal spikes
- characterized by noctural seizures
(b) Rarely needs tx, children only have a few seizures, always remits by age 16
What is Miller-Fischer Syndrome?
Variant of Guillain-Barre (acquired neuropathy) that presents w/ descending symptoms and most prominently opthalmoplegia (weakness of eye muscles
-also w/ areflexia and ataxia (but usually no limb weakness)
-associated w/ Anti-GQ1b antibodies
25 yo referred for episodes of altered behavior lasting 2 mins w/ lip-smacking and repetitive behavior
-pt doesn’t remember events, feels “butterflies in my stomach” and a sense of fear, and smells burning rubber, before they occur
Most likely dx
Complex partial seizure
What are meningiomas?
(a) imaging finding
(b) Prognosis
Meningiomas = tumors arising from the meninges = membranous layer covering of the CSF
(a) Dural tail
(b) 90% benign => often don’t even require tx (can observe)
What feature strongly suggests a non-epleptic seizure?
Non-epileptic (pseudo) seizure suggested by convulsion in the doctor’s office or waiting room
-not associated w/ comorbid mood d/o
Differentiate the location of CNS tumors in children vs. adults
Majority (2/3) in adult are supratentorial (in the cortex) while majority (2/3) in children are infratentorial
ex of infratentorial = medulloblastoma (cerebellar)
Tuberous sclerosis
(a) Etiology
(b) Characteristic lesion
(c) First step in tx
Tuberous sclerosis
(a) Aut dom inherited neurocutaneous d/o
(b) Benign tumors in brain (cortical tubers/glioneuronal hamartomas, kidney, skin, lungs)
(c) ACTH, to suppress CRH release in hope of preventing associated infantile spasms
Diagnostic criteria for Tourette’s
Need both motor and at least one vocal tic
-starting before age 18 and lasting for 1+ year w/o tic-free period of more than 3 mo
Tx for Guillain Barre
Best tx = IVIG and supporitve care (airway protection, required by about 30%)
-equal in efficacy, but much easier and fewer side effects, than plasmaphoresis
-no role for steroids in tx of GB
CNS presentation of Wilson’s disease
Most commonly will present w/ liver failure, but can present initially w/ CNS signs: generally any movement d/o and dysarthria (speech disturbance) 2/2 basal ganglion abnormality
-classic finding = wing-flapping tremor
Temporal arteritis
(a) Most feared complication
(b) Tx
Temporal/giant cell arteritis
(a) unilateral vision loss
(b) Start prednisone ASAP
Differentiate genetics of Prader-Willi vs. Angelman’s
Prader-Willi = deletion of normal paternal contribution of chrom 15
-hypotonia, MR, obesity
Angelman’s = deletion of normal maternal contribution of chrom 15
-MR, hand flapping/jerky mov’ts, seizures
Differentiate conduction velocity and conduction amplitude findings on nerve conduction studies
Decrease in conduction velocity = demyelinating process
-same amount of nerves, signal just going slower
Decrease in amplitude = axonal process
-fewer nerves, but speed of those nerves is preserved
Mentally retarded infant develops seizures, facial birthmark
(a) Dx
(b) Expected MRI findings
(c) Additional expected findings
(a) Sturge-Weber syndrome
(b) Ipsilateral (same side as port-wine stain) leptomeningeal angioma causing gradual calcification and atrophy of underlying brain
(c) Seizures starting in infancy: can be severe enough to warrant hemispherectomy
- glaucoma
- port-wine stain 2/2 capillary overgrowth, most commonly in V1 (opthalmic) distribution
- neuronal loss and calcification in cerebral cortex ipsilateral to birth mark
Overall: MR, seizures, port-wine stain, glaucoma, ipsilateral leptomeningeal angioma
Differentiate tremor from chorea
Tremor- rhythmic
-alternating contraction btwn agonist and antagonist muscles
Chorea- not repetitive or rhythmic
-flow from one muscle group to the next
Pt observed to suddenly lose consciousness and have tonic-clonic mov’ts, you hear your pager and arrive w/in 1 minute
-pt is still seizing at this time, next step?
Next step at this point = observation
-ABCs
Tx for IV Lorazepam if it lasts 5-10 minutes or more
(a) What is Todd’s paralysis?
(b) Most common manifestation?
(a) Todd’s paralysis/phenomenon = focal neurologic deficit that persists for an extended period (but under 28 hrs) after a seizure
(b) Usually transient weakness of involved limb (arm, hand, leg), but can be sensory, visual, speech etc depending on part of brain where the seizure activity occured
35 yo M falls off bike and hits head on the ground, no LOC
- 30 mins later: turns white as a ghost and falls to the ground, some shaking mov’t of arms and legs
- gets up w/in mins and seems fine
Dx
Dx = syncopal event
-vasovagal syncope, specifically convulsive syncope: many pts can have convulsive movements during syncope
Name 2 meds that can cause myopathy
Muscle aches/pains
- statins (high dose)
- chronic corticosteroids
Features of Rett’s syndrome
Normal development until 1-4 yoa, stagnation then decline in both cognitive and physical fxn
- lose of purposeful hand movements, inability to speak
- almost only female
- gray matter disease
- small hands/feet, decelerated head growth
- repetitive stereotyped hand movements
Classification for primary CNS tumors
Glial origin
-astrocytoma, glioblastoma, oligodendroglioma, ependymoma, choroid plexus papilloma/carcinoma
Non-Glial Origin
- meningioma
- primary CNS lymphoma
Surgical procedures done in epilepsy
(a) Most common
(b) Most aggressive
(a) Removal of the temporal lobe
(b) Corpus callostomy- used in refractory epilepsy to prevent partial seizures from spreading into generalized
In which pt would IV phenytoin be indicated as seizure ppx
Pt w/ severe head trauma: in pts w/ severe head trauma ppx anticonvulsants decreases initial seizure rate, but does not have any impact on long-term seizure rate
-no role for seizure ppx in brain tumors or intracerebral bleeds
What presents w/
(a) Ascending paralysis
(b) Descending paralysis
(a) Ascending paralysis = Guillaine-Barre, tick paralysis, transverse myelitis, spinal cord compression
(b) Descending paralysis = Botulsim
West syndrome
(a) What is it?
(b) Best tx
West syndrome = epilepsy d/o of infantile spasms
(a) Triad:
1. infantile spasms
2. pathognomonic EEG pattern of hypsarrhythmia (high amplitude waves and a background of irregular spikes
3. mental retardation/developmental regression
(b) Hard to tx, mainstay is to give ACTH
Tx for pseudotumor cerebri
(a) First line
(b) Next steps
(c) Treating RF
Pseudotumor cerebri
(a) Acetazolaminde = carbonic anhydrase inhibitor to decrease CSF production
(b) Optic nerve sheath fenestration to prevent blindness, can do serial LPs or VP shunt
(c) Bariatric surgery for wt loss shown to be effective
Test to confirm myasthenia gravis in first visit
Tensilon test = edrophonium = readily reversible AChE inhibitor that improves muscle weakness, while worsening weakness seen in cholinergic crisis
Concern when starting pt on lamotrigine
Lamotrigene (Lamictal) has to be titrated slowly to therapeutic dose 2/2 association w/ Steven-Johnson syndrome
-when starting lamotrigine, be cautious of new onset rash
Familial hemiplegic migraine
Aut dom migraine d/o w/ hemiparesis during the migraine aura
Otherwise 65 yo M has first seizure of his life, suspected dx?
Brain tumor
-rate of epilepsy declines significantly after 60 (highest in early childhood ages 0-14)
What anti-epileptic med is contraindicated in pt w/ a h/o kidney stones
Topiramate (Topamax)
Pt has sudden LOC and tonic-clonic mov’t of extremities w/ urinary incontinence and tongue-biting
Type of seizure?
Primary generalized seizure
Define epilepsy
2 or more unprovoked seizures
Albuminocytologic dissociation
CSF finding of high protein w/ normal cell count seen in Guillain-Barre
-but not seen acutely, takes about a week to develop
MRI findings in tuberous sclerosis
- cortical tubers (tubers…tuberous)
- subependymal nodules
- subependymal giant cell astrocytomas = benign but can enlarge and obstruct CSF flow
- ventriculomegaly
76 yo M develops constant dull pain in the side of his head that is worse w/ chewing
Dx
Dx = temporal arteritis- over 60 yoa, indolent headache in the temple, jaw claudication
Distinguishing features of Lew Body Dimentia vs. Parkinsons
Early onset dementia, hallucinations, hypersensitivity to antipyschotics
LBD: fluctuating alertness/awareness
