Clinical EEG Rhythms

1
Clinical EEG Rhythms
2
Eyes Closed Baseline
3
Eyes Open Baseline
4
Spectral Plot is one way to present frequency and
amplitude information start here
5
Brain Maps
6
Topometrics
7
Frontal Slowing during Math Abnormal
8
Numbers for Statistical Analysis

• Quantitative EEG (QEEG)

9
Some of the signal properties that can be
quantified
10
Also between-site differences

• Absolute Magnitude
• Relative Magnitude
• Asymmetry
• Coherence

11

• Attenuation of temporal lobes
• Beta1SMR
• Waveform morphology
• Bipolar
• Non-specific arousal

12
Role of Topography and Timing
13
(No Transcript)
14
Waveform morphology
15

• Power vs Magnitude
• Squared microvolts vs microvolts

16
Cross-spectral analysis
Coherence estimates phase consistency
Comodulation estimates magnitude consistency
between signals at each specified
frequency Coh average normalized
cross-spectrum amplitude2 Comod average
normalized cross-product amplitude Coh
range from 0.0 to 1.0 Comod range from -1.0
to 1.0 Confusing point Tukey called coherency
the square root of coherence
17

• Signals are coherent when phase relationship is
  stable

• Signals are comodulated (or hypermodulated) when
  magnitude relationship is stable

18
Comodulation
19
Each site compared to all others ( itself) in
each head
20
An individuals data (rho) and his/her
statistical (z) comparison to the database
21
MTBI patient Rage Disorder
22
Hypermodulation
23
Hypomodulation
24
Current EEG Applications

• CLINICAL
• Epilepsy (1930s)
• Sleep (1940s)
• Patient monitoring, anaesthesia
• Head injury assessment
• Neurological assessment (AEP, ERP)
• Neurotherapy
• Psychiatric assessment

25
Current EEG Applications

• SCIENTIFIC
• Attention
• Workload
• Circadian rhythms
• Cognition
• Learning Memory
• Neuroimaging co-registration

26
Future EEG Assessment

• Subtype clinical conditions
• Monitor attentional state
• Lie Detection
• Parole disposition