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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