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EEG: New Applications in Psychiatry?
Introduction
EEG as a confirmatory test in epilepsy Child presenting with school difficulty
Acute confusional state
Psychogenic non-epileptic spells Example 1 Example 2
Outline
Digital Processing of EEG
EEG in ADHD
EEG in depression
EEG in Autism
EEG
EEG
Digital Processing: Matrix
Sampling (200/sec)
20
ch
an
nels
200 values/sec
SR*time (sec)
Nb
of
Ch
Digital Processing: Matrix
Digital Processing
Spectral analysis
Coherence
Spectral Analysis
Fourier transform is a mathematical procedure that breaks a a function into the frequencies that compose it
FT
Spectral Analysis
MusicEEG
Spectral Analysis
Digital Processing: Spectral analysis
EEG: Artifacts
EEG: Artifacts
Digital Processing: Coherence
Coherence of two Random Signals
Coherence in EEG
Coherence in EEG
Coherence in EEG
Outline
Digital Processing of EEG
EEG in ADHD
EEG in depression
EEG in Autism
Neuropsychiatric EEG-Based Assessment Aid
Neuropsychiatric EEG-Based Assessment Aid
EEG in ADHD
A meta-analysis was performed on quantitative EEG studies that evaluated ADHD using the criteria of the DSM-IV
Nine eligible studies (N = 1498) were included Increased beta/theta power compared to
control Pooled effect size of 3.08 (95% confidence
interval 2.90 to 3.26) for ADHD versus controls (normal children, adolescents, and adults)
This effect size of 3.08 predicts a sensitivity and specificity of 94%
J Clin Neurophysiol. 2006;23(5):440-455.
EEG in ADHD
Do we really need NEBA to diagnose ADHD? Pathophysiology
Outline
Digital Processing of EEG
EEG in ADHD
EEG in depression
EEG in Autism
PSG in Depression
Latency to REM = 24.50 Minutes
(i) impaired sleep continuity (prolonged sleep latency, increased number of intermittent awakenings, early morning awakenings),(ii) disinhibition of REM sleep: shortened REM latency or sleep onset REM periods (SOREMPs, REM latency 0–20 min) prolonged first REM period, elevated REM density (measure of the frequency of rapid eye movements) particularly duringthe first REM period,(iii) changes of non-REM sleep (decrease of SWS, and sleep stage 2,).(IV) decreased delta power throughout the night
REM and Antidepressants
Journal of Psychiatric Research 44 (2010) 242–252
Quantitative EEG Cordance in Depression
1) Absolute and relative power2) z-transformed to measure deviation from the mean valuesfor that recording3) z scores were summed to yield a cordance value for each electrode in each frequency band
Am J Psychiatry 2006; 163:1426–1432
Quantitative EEG and Response to Treatment
A decrease in prefrontal cordance during the placebolead-in period were associated with lowerfinal Hamilton depression scale scores insubjects randomly assigned to medication.Prefrontal changes explained 19% ofthe variance in final Hamilton depressionscale scores.
Am J Psychiatry 2006; 163:1426–1432
Outline
Digital Processing of EEG
EEG in ADHD
EEG in depression
EEG in Autism
Autism and Coherence
In one study carried out in 20 children with autistic disorder and gender, age, and IQ-matched controls, the autism group had increased theta power in the right posterior region, decreased frontal delta power, increased midline beta power, decreased intrahemispheric delta and theta coherence, decreased delta and theta coherence frontally, and decreased delta, theta, and beta coherence posteriorly
In another study of 18 adults with autistic disorder and 18 controls, those with autistic disorder were found to have increased power in the 3 to 6 Hz and 13 to 17 Hz bands and less 9 to 10 Hz power as well as elevated theta coherence in the left frontal temporal regions and between frontal and all other regions.
1- Clin Neurophysiol. 2008;119(5): 1002-1009.2- Biol Psychiatry. 2007;62(3):270-273.
Autism and Coherence
Autism Res 2014, 7: 334–343
In Nineteen children with high-functioning ASD: displayed reduced coherence at the alpha frequency between the left and right temporal-parietal lobes in all conditions and reduced coherence at the alpha frequency between left and right frontal lobes during baseline. No group differences in intrahemispheric coherence at the alpha frequency emerged at the chosen statistical threshold. Results suggest decreased interhemispheric connectivity in frontal and temporal-parietal regions in children with ASD compared to controls.
Multivariate Approaches To Coherence analysis
The simplistic coherence pairwise measurements do not represent the true and quite complicated picture of connectivity anomalies in autism
Different forms of multivariate connectivity analysis with increasing levels of sophistication (including one based on principle components analysis, sLORETA source coherence, and Granger causality)
This multivariate analysis resembled structural connectivity (MRI-DTI)
Frontiers in Human Neuroscience 2014;8: 1-12
Multivariate Approaches To Coherence analysis
Frontiers in Human Neuroscience 2014;8: 1-12
Conclusions
Signal analysis applied to EEG in psychiatric diseases is a promising new technology
Limitations Clinical applications Best signal analysis technique
What are we measuring? What is the best mathematical construct?
Physiologic basis of the EEG EPSP and IPSP
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