Neuroscience - Block 3 - Part 3

davidwurbel7's version from 2016-04-04 04:14

EEG’s and Seizure Disorders

Question Answer
Composed of 21 electrodes; 19 on head, 2 on earsEEG
Alpha8-13 Hz
Beta14-30 Hz
Theta4-7 Hz
Delta1-5 Hz
Gamma30-100 Hz
Mu8-13 Hz
8-13 HzAlpha Waves
14-30 HzBeta Waves
4-7 HzTheta Waves
1-5 HzDelta Waves
30-100 HzGamma Waves
8-13 HzMu Waves
Waves present in the awake resting state. Alpha waves disappear during sleep, and decrease with eye opening or mental exertionAlpha Waves
Occur during activation of nervous system (during sensory input and mental activity). Activity decreases during motor movementBeta Waves
Occurs in children and adults during emotional stress. They also occur during some mental disorders. Interestingly, can also appear during meditative or ‘creative’ statesTheta Waves
Occur during deep sleep in adults, and also in awake infants. If these waves are present in awake adults they likely indicate brain injuryDelta Waves
Groups of neurons working together for a specific cognitive or motor taskGamma Waves
Overlaps with other frequencies. Reflects the synchronous activity of motor neurons in the resting stateMu Waves


Question Answer
The EEG is believed to be generated by this from excitatory and inhibitory cortical nerve cellPostsynaptic Potentials
The EEG is the leading test used to help diagnose thisSeizures
The actual seizureIctis (Ictal)
Period immediately following the seizurePostictis (ictal)
Period between seizuresInterictal
Continuous seizures or clusters of seizuresStatus Epilepticus
Rapid, brief contraction of body muscles. Usually involves arms or feet/legsMyoclonic Seizure
‘Petit Mal’. Periods of lack of awareness, usually lasting less than a minute.Absence Seizure
Abrupt loss of muscle tone. Might need to wear a helmet with this oneAtonic Seizure
Area of seizure is limited to one region of the bodyPartial Seizures
Involves no loss of consciousnessSimple Partial Seizure
Consciousness is lost or impaired. A common feature is picking (ie picking at clothes)Complex Partial Seizure
One time only. No family history of seizures. (induced by drugs, anesthetics, or unknown).First Seizures
Seizures occurring during high fever in childrenFebrile Seizures
Looks like a seizure but no change in EEG. PTSD, panic disorder, are examples, as are factitious (Munchausen’s)Dissociative Seizures
Diabetes, syncope, migraine, stroke, tumor, etcOrganic Caused Seizure
Neurotransmitter imbalance - Low GABA levels in some patients. Some anti-seizures meds are GABAergic. Brain damage/trauma/disease: Irritative lesions can result in seizures. Environmental - Drug use or disuse, lack of sleep, stress, toxins.Etiology of Seizures
Treatment of seizures with Dilantin (phenytoin) and Tegretol (carbamazepine)Anticonvulsant Medication
Treatment method by stimulating electrode ‘wrapped’ around the left vagus nerveVagus Nerve Stimulation (VNS)
Seizures that do not originate from physical causes, thus are treated with therapy and often adjunct medsPsychogenic Seizures
Reticular Formation, Serotonin (5-HT), Adenosine, Acetylcholine, Hypothalamus are involved with thisSleep/Wakefulness
The part of the RF involved in Sleep/Waking Ascending Reticular Activating System (ARAS)
The part of the RF that drives the cortexMidbrain ARAS
The part fo the RF that turns off midbrain (for sleep).Pontine ARAS
The part of the RF that generates REM sleep (and somatic muscle inhibition)Pontine ARAS
Caffeine is an antagonist which binds to this receptor on ACh neuronsA1 Receptor
This neurotransmitter is responsible for binding to ACh neurons, inhibiting them resulting in sedation/sleepAdenosine


Question Answer
By release of excessive and uncontrolled electrical activity in the brainSeizure
A neurological condition, that in different times produce brief disturbances in the electrical functions of the brain. 2 or more unprovoked seizuresEpilepsy
An area of the brain in which seizure activity spreads through the brain if untreatedKindling
Onset: Entire brain at once. Generalized symptoms and EEG changesPrimary (Idiopathic) Generalized Epilepsy
Onset: Specific part of the brain Focal symptoms, focal EEG changesFocal Epilepsy
Absence seizures (i.e. “Petit Mal”), Myoclonic (as seen in Juvenile Myoclonic Epilepsy), Primary generalized tonic-clonic seizures, Tonic, Clonic and Atonic are examples of this type of seizureGeneralized Epilepsy
Temporal lobe seizures, Frontal lobe seizures, Occipital lobe seizures and Secondarily generalized tonic-clonic seizuresFocal epilepsy
<4Hz (sleep)Delta
8-13Hz (when predominant posterior rhythm awake, relaxed, with eyes closed)Alpha
>13Hz (anterior head regions, increased in people on benzodiazepines/barbiturates)Beta
Sudden intense fear, déjà vu, jamais vu, olfactory or gustatory hallucinations, rising abdominal sensation. Moving sensory symptoms. Visual. MotorEpilepsy Auras
Generalized spikes from onset on EEG. No auras. Sudden LOC, might have cry. Last 2-3 minutes, with post-ictal period of confusion. May have urinary/fecal incontinence, frothing, tongue biting. Amnestic for the eventGeneralized Tonic-Clonic
Sudden behavioral arrest. Staring, unresponsive, eye blinking. Sudden return to normal without prevent amnesia common. Most young children (told daydreaming). Typical petit mal: triggered by hyperventilation, regular generalized 3/second spike and slow wave. Atypical spike and wave often with static encephalopathyAbsence Seisures
Brief, lightening like, whole body or portion, often no LOC. May be triggered by lights/startle. May or may not be epileptic (need EEG to distinguish)Myoclonic Seizures
Hippocampal sclerosis is the most common pathologic abnormality in temporal lobe epilepsy (TLE). Neuronal loss in the CA1, CA3 and CA4 regions of the hippocampus, atrophy and gliosis. Presentation is usually with an aura of rising epigastric sensation, impaired consciousness and oroalimentary (lip smacking) automatisms. Important cause of refractory epilepsy. EEG -> anterior temporal spikes. MRI brain -> T2 weighted images show hyperintensity and atrophy of the involved hippocampusMesial Temporal Sclerosis (MTS)
Most focal seizures begin in temporal lobe. Auras: epigastric rising feeling, intense fear (amygdala involved), déjà vu, olfactory hallucinations. Automatisms common (lip smacking or chewing, button picking)Temporal Lobe Seizures
Only seizure that can be bilateral without loss of awareness. Often nocturnal, brief vocalizations, shaking, forced head turning to one side, Jacksonian marchFrontal Lobe Seizures
Rare, since this is not a very epileptic location. Poorly formed colors with lights. Might see complex forms, often stereotypedOccipital Lobe Seizures
Adolescence. Usually family history of epilepsy. Myoclonus early in day (drops things). Requires treatment lifelongJuvenile Myoclonic Epilepsy
Unilateral paresthesiae involving tongue, lip, cheek. Unilateral clonic activity involving face, lip, larynx: causing speech disturbance (arrest). Drooling. Intact consciousness before secondary generalization. Usually shortly after falling asleep. EEG diagnosis. Resolves by adolescenceBenign Epilepsy with Centrotemporal Spikes (Rolandic Seizures)
3-12 months of age. Sudden jerk followed by stiffening. Treat with ACTHInfantile Spasms (West Syndrome)
Triad of mental retardation, slow spike and wave and multiple seizure types (often absences). Tonic seizures out of sleep. Diagnosis made earlier than age 8. Treatment difficultLennox-Gaustat syndrome
Sudden loss, may be head nod or fall. Can be injured. Often begins in childhood and lasts until adulthoodAtonic Seizures
Simple: less than 15 minutes with shaking. 3 months to 5 years with fever. Benign: treatment not requiredFebrile Seizures
A condition a seizure lasts more than 30 minutes , or multiple seizures lasting 30 minutes without recovery in between. May be life-threatening with the development of pyrexia, deepening coma and circulatory collapse. May require intubation. Needs EEG monitoring. Treatment: intravenous lorazepam, diazepam, phosphenytoin, valproate, and general anesthesia if neededStatus Epilepticus
Usually NOT Stereotyped. Side-to-side head or body turning (“jacitation”), pelvic thrusting. Asynchronous body movements (may involve thrashing and writhing movements). Discontinuous motor patterns. Prolonged duration, rapid recovery. Eyes closed, face not involved. Crying during or after event. Situational triggersPsychogenic Non-Epileptic Seizures (Pseudoseizures)

Nutritional Disorders

Question Answer
Children develop behavioral and IQ impairment. Adults develop abdominal pain and constipation and wrist drop (motor neuropathy), encephalopathy, unusual taste in mouth, hypochromic, microcytic anemia. Discoloration of the upper gum margin (Burton’s line)Lead Poisoning
Encephalopathy, sensorimotor neuropathy, seizures, tremor. Metallic tasteMercury Poisoning
Encephalopathy, painful neuropathy, nausea, vomiting, diarrhea, renal failure, arrhythmias. Urine test better than bloodArsenic Poisoning
Vomiting, diarrhea, paresthesias (small fiber neuropathy), cognitive impairment. Late hair lossThallium Poisoning
Confusion, irritability, compulsive behavior, then Parkinson’s disease symptoms. Hyperreflexia. Seen in arc welding supplies, steel industry, dry cellsManganese Poisoning
Balanced starvation” (deficient in all nutrients). Insufficient breast milk. Dilute milk mixture or lack of hygiene. Wasting (up to 80% of normal weight). Mental changes, growth retardationMarasmus
Between 1-3 yrs. old. encephalopathy, muscle wasting. Very low protein but w/calories from carbohydrates. In places where starchy foods are main staple (clay/dirt/Argo starch eating). Due to famine, limited food, low levels of education about diet. When seen in US, usually due to child abuseKwashiorkor
Generalized, excessive accumulation of fat in subcutaneous & other tissues. Excessive intake of food compared w/ utilization. Genetic constitution. Psychic disturbance. Endocrine & metabolic disturbances rare. Insufficient exercise or lack of activityObesity
Rare complication of extreme exogenous obesity. Severe cardiorespiratory distress & alveolar hypoventilation. Includes polycythemia, hypoxemia, cyanosis, CHF & somnolence. High O2 concentrations dangerous in cyanosis. Weight reduction ASAPPickwickian Syndrome
Excessive daytime sleepiness, oxygen desaturation, arrhythmiasSleep Apnea
Dementia. “Ischemic” cranial nerve palsies. Peripheral neuropathies. Plexopathies. Mononeuritis multiplex. Blindness. Increased risk of stroke. Loss of limbs (vascular complications)Debetes Melitis
Learning difficulties, Mental retardation, Behavioral difficulties, Microcephaly, Hypotonia, Growth impairment, Short palpebral fissure, Cataracts, Hypoplastic maxilla, Hypoplastic philtrumFetal Alcohol Syndrome
Over vigorous correction of hyponatremia, alcoholism, liver disease, malnutrition Get severe paralysis, dysphagia, dysarthriaCentral Pontine Myelinolysis
Demyelination of corpus callosum. Seen in chronic alcoholism. Rapid psychosis, stupor and coma, death (mild forms exist)Marchiafava-Bignami disease
Truncal ataxia. Unclear how much due to alcohol/nutrition. Unlikely to respond to treatment. Alcoholic cerebellar degeneration. Encephalopathy. If repeated bouts of hepatic encephalopathy, hepatorenal syndrome with dementia and ataxia. AsterixisHepatic Disease Associated with Alcoholism
When due to alcohol, length dependent sensory or sensorimotor neuropathy. pain invariable. Can also be due to fad diets, dialysis, bariatric surgery. starts with weakness or numbness, rapid progressionPolyneuropathy Thiamine Deficiency
Ataxia, ophthalmoplegia, confusion. Typically due to impaired absorption or poor intake of thiamine (as in alcoholism), HIV, hyperemesis gravidarum. Typically have nystagmusWernicke’s Encephalopathy
Anterograde amnesia. Memory loss anterograde (striking short term), retrograde amnesia. Confabulation. Apathy, impaired executive functions, lack of insight, dementiaKorsakoff’s Psychosis
Due to insufficient neurotransmitter synthesis, such as irritability, depression & somnolence. Usually seen in infancy, intractable seizures within hours of birth. Rare; but death if untreatedPyridoxine Dependent Seizures
Progressive spinocerebellar syndrome and peripheral neuropathy. Dry hair or baldness. Muscle weakness. Leg cramps. Blindness. May be due to GI, pancreatic, hepatic diseaseVitamin E Deficiency

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