Measurement of neurophysiology Flashcards
Number of electrodes used in standard EEG
21
Procedures that are used to elicit abnormalities in EEG
Hyperventilation
Strobe lighting
Sleep deprivation
Frequency of beta waves in EEG
13-30Hz
Frequency of alpha waves in EEG
8-13Hz
Frequency of theta waves in EEG
4-8Hz
Frequency of delta waves in EEG
<4Hz
Frequency of Mu waves in EEG
7-11Hz
Waves described as fast waves in EEG
Beta
Alpha
Waves described as slow waves in EEG
Theta
Delta
Wave seen at the frontal, central position on a normal waking EEG when busy or concentrating
Beta
Most common wave seen in awake but eyes closed, relaxing EEG
Alpha
Wave prominent in sleep in EEG
Theta
Wave prominent in deep sleep in EEG
Delta
Factors that cause alpha waves to disappear in EEG
Anxiety
Eyes opening
Arousal
Focused attention
EEG wave which is suggestive of pathology if seen in large amounts during waking
Theta
EEG wave which is suggestive of pathology if seen at all in waking EEG
Delta
Characteristics of Mu waves in EEG
Related to motor activity
Arch like waves
Caused by movement of the contralateral side
Characteristics of Lambda waves on EEG
Single, occipital, triangular, sharp wave
Produced by visual scanning e.g. reading a line of text
Characteristics of normal EEG in newborns
Dominant delta and theta waves
Characteristics of normal EEG in babies
Irregular medium to high frequency delta waves
Characteristics of normal EEG in early childhood
Posterior alpha waves developing
Age at which a child’s EEG becomes similar to an adult’s
12-14
Characteristic EEG in absence seizures
Regular 3Hz waves
Characteristic EEG in Alzheimer’s dementia
Increase in lower frequency waves
Rarely normal in advanced Alzheimer’s dementia
Characteristic EEG in Angelman’s syndrome
Long runs of 2-3Hz frontal activity with epileptiform discharges
Occipital 4-6Hz occipital activity on eye closure by the age of 12
Characteristic EEG in ADHD
Spike or spike and wave pattern in 60%
Characteristic EEG in borderline personality disorder
Spikes in 25% of patients
Characteristic EEG in CJD
1-2Hz sharp waves every 1-2 seconds in 90% of patients with sporadic CJD
Less often seen in familial CJD
Not seen in variant CJD
Characteristic EEG in subdural haematoma
Focal delta slowing
Characteristic EEG in herpes simplex encephalitis
Episodic discharges every 1-3 seconds over temporal areas
Characteristic EEG in Huntington’s disease
Initially loss of alpha waves
Later flattened wave
Characteristic EEG in infantile spasms
Hypsarrhythmia - diffuse giant waves with a chaotic background
Characteristic EEG in infectious disorders
Diffuse, synchronous high voltage slowing
Characteristic EEG in metabolic or endocrine disorders
Diffused generalised slowing
Characteristic EEG in hepatic encephalopathy
Triphasic waves
Widespread slowing
Characteristic EEG in neurosyphilis
General increase in slow waves
Characteristic EEG in seizures
Generalised, hemispheric, or focal spike or spike/wave discharge
Characteristic EEG in stroke
Delta activity
Characteristic EEG in structural lesions
Focal slowing or focal spike
Most common EEG abonrmality
Diffuse slowing
Effect of antipsychotics on EEG
Slowing of beta
Increase in alpha, theta and delta
Mild instability of waveforms
Effect of antidepressants on EEG
Slowing of beta
Increase in alpha, theta, delta
Effect of lithium on EEG
Slowing of alpha
Effect anticonvulsants on EEG
No effect
Effect of barbiturates on EEG
Increased beta activity
Effect of barbiturate withdrawal on EEG
Generalised paroxysmal activity
Spikes
Effect of benzodiazepines on EEG
Increased beta
Decreased alpha
Effect of benzodiazepine overdose on EEG
Suppressed rhythm
Excess fast waves/beta waves
Effect of opiates on EEG
Decreased alpha
Increased voltage of theta and delta
Effect of opiate overdose on EEG
Slow waves
Effect of alcohol intoxication on EEG
Increased alpha activity
Increased theta activity
Effect of alcohol withdrawal on EEG
Increased beta
Characteristic EEG in delirium
Slow waves
Characteristic EEG in delirium tremens
Beta activity
Effect of marijuana on EEG
Increased alpha in frontal area
Overall slow alpha activity
Effect of cocaine on EEG
Increased alpha activity in frontal area
Overall slow alpha activity
Effect of nicotine on EEG
Increased alpha
Effect of nicotine withdrawal on EEG
Decrease in alpha activiy
Effect of caffeine withdrawal on EEG
Increase in amplitude of theta waves
Measurement technique used to measure the magnetic fields produced by electrical activity in the brain
Magnetoencephalography (MEG)
Age at which EEG changes are seen in Angelman’s syndrome
2
Characteristic EEG in subacute sclerosing panencephalitis
Bilateral symmetrical polyphasic sharp wave and slow wave complexes every 4-15 seconds
EEG seen immediately after ECT treatment
Delta and theta excess
Time after ECT treatment for EEG to return to normal
3 months
Percentage of healthy individuals who show EEG abnormalities
10-15%
Percentage of epileptic patients who show normal EEG between seizures
30-50%
Characteristic EEG in atypical absence seizures
<2.5Hz generalised spike and wave
Characteristic EEG in focal seizures
Focal spikes
Characteristic EEG in myoclonic seizures
3-6Hz polyspike and wave discharge
Characteristic EEG in generalised tonic clonic seizures
Generalised fast rhythmic spikes in tonic phase
Burst of spikes and slow waves in clonic phase
Characteristic post ictal EEG
Irregular slow activity
Characteristic EEG in atonic seizures
Generalised spike and wave
Slow waves during atonia
Frequency of gamma waves
30-100Hz
Wave seen normally in advanced meditators
Gamma
Changes in EEG seen in variant CJD
No typical changes
EEG findings in normal aging
Diffuse or focal slowing
If focal most often present in the left temporal region
Alternative name for sleep spindles
Sigma waves
Stage of sleep sigma waves occur in
Stage II
Disease characterised by loss of sigma waves
Familial fatal insomnia
Area of the brain where sigma waves are generated
Thalamus
Effect of lithium toxicity on EEG
Generalised slowing with triphasic waves
EEG wave most suggestive of a SOL in the brain
Delta waves
Characteristic EEG in HIV infection
Diffuse slowing
EEG seen in frontotemporal dementia
Usually normal
Area of the brain where alpha waves are most frequently seen
Occipital regions