EEG board prep 2023 exam with complete solutions

Mu Rhythm -c3/c4 region -7-11Hz -does not block with eye opening -easy to see with eyes open -blocks unilaterally with contralateral hand -asymmetrical and asynchronous -NORMAL Beta ->14 HZ -detected during wakefulness, enhanced during drowsiness, and decreased in deeper sleep -seen on barbiturates and benzodiazepines Lambda waves -NORMAL, awake -sharp waves occurring in occipital region (o1/o2) during wakefulness -visually scanning a picture in a lit room -physiological, eyes OPEN -saccadic eye movement -4-6hz Small sharp spikes / BETS -occurs in stage 1/stage 2 -peaks at 30-60 years -temporal region -occurs sporadically and short duration -NORMAL benign variant Wicket Spikes -Single spike or 6-11 hz Mu like shape seen in drowsiness and light sleep. -mid temporal region -seen in adults over 30 -NORMAL benign variant 14&6hz positive spikes -posterior/temporal region (t5/t6) -normal benign variant -light sleep -best seen in referential montage -runs last less than 2 seconds -seen in a lot of adolescents sleep spindles -11-14hz , 1/2 second duration -central regions -asynchrony is abnormal after 2years old -stage 2 sleep Hypnagogic Hypersynchrony -2-6years old -central/frontal regions -paroxysmal bursts high voltage, 3-4.5hz -normal variant of drowsiness Dilantin toxicity ataxia (loss of control of body muscles) Laplacian montage -source reference deviation -looks at only the electrodes that are closest to the point of interest -emphasizes localized waveforms deja vu -complex partial sz -automatisms/impaired consciousness extreme spindles -found in MR (mental retardation) patients -high voltage, anterior dominant -generalized OIRDA (Occipital Intermittent Rhythmic Delta Activity) -encephalopathy eeg pattern most associated with children -high amplitude, saw toothed, and reactive to eye opening Rolandic Spikes -seen in children -cento/temporal -seen in benign rolandic epilepsy FIRDA -Frontal Intermittent Rhythmic Delta Activity -reacts to stimulation -2-3hz -rhythmic -awake adult eeg Atonic seizure (drop attack) generalized seizure characterized by sudden loss of muscle tone and strength; may cause the head to drop suddenly, objects to fall from the hands, or the legs to lose strength, with falling and potential injury Tonic seizure Muscle stiffness, rigidity photomyogenic response -normal physiological response to photic light -frontal leads -only seen with eyes closed Photoparoxysmal response -abnormal response to photic -spikes, polyspikes, or spike/waves -mostly seen in FQ >10hz HV contraindications recent subarachnoid hemorrhage, recent stroke, sickle cell disease, intracranial hemorrhage, old age, heart and/or breathing problems photic contraindications subarachnoid hemorrhage, recent eye surgery tonic (tonic/clonic sz) muscle artifact, generalized voltage suppression -stiffening/contracting of muscles clonic (tonic/clonic sz) rhythmic twitching or jerking of muscles -spike and slow wave Posterior Slow Waves of Youth -8-14 years old -accentuated by HV -high voltage theta/delta -occipital regions SREDA (subclinical rhythmic electrographic discharges in adults) -suddenly in resting EEG -periodic sharp activity that progresses into a monorhythmic theta pattern -seen in mostly normal adults over 50 By age 1, what should the background rhythm be? 5-6Hz what pattern is seen after cardiac arrest? alpha coma EEG obtained during sleep are most important in what type of seizures? complex partial seizures Sleep stages in tern newborn are characterized by: onset active sleep What montage are 14&6 positive spikes are best seen in? contralateral ear reference At what age does posterior background rhythm become reactive to eye closure? 3-6 months Sleep onset REM = narcolepsy POSTS -stage 1 sleep, sometimes in stage 2 -4-5hz -occipital channels MU vs Alpha -Mu occurs in c3/c4 -alpha occurs in o1/o2 -mu and alpha have the same fq 8-13hz -mu does not go away when eyes are open, unlike alpha What different scenarios do you see normal EEG activity ? -multiple sclerosis -cerebellar abscess -following an absence seizure -early Alzheimer's -two days after a TIA -down syndrome -inter-ictal of febrile seizures What scenarios would you see PLEDS in EEG? -cerebral embolus -acute cerebral infarction -herpes simplex encephalopathy* -ischemic stroke* Asperger's syndrome Mild form of autism; may have concomitant learning disabilities and/or poor motor skills. what scenarios would you see bi-pleds? (both hemispheres but independently) -anoxic encephalopathy -hypoxia Proprioception -temporal lobe -our sense of body position Frequencies of EEG Delta - 0-4hz Theta - 4-7hz Alpha - 8-13hz Beta- 14+hz physiological artifacts originate from the body outside of the brain -ex: muscle, pulse, eye mvt, respiration, sweat non-physiological artifacts originates from the environment, not the body ex: electrodes, 60hz from equipment, etc secondary bilateral synchrony -reflects rapid generalization from one or more sources -abnormality starts on one side of the body and spreads to the other side eventually When should you see Delta? -background in infants >1yr -stage 3 sleep -OIRDA posteriorly in children -FIRDA frontals in adults -generalized with diffuse lesions -focally with subcortical lesions -ABNORMAl in awake adults When should you see Theta? -sleep ABNORMAL in awake adults