I have recently recorded EEG (linked ears reference) from a young man (18 years old) in order to evaluate the possibility of attention deficit hyperactivuty disorder (ADHD) by looking at his theta/beta ratio. While he had a relatively normal theta bata ratio with eyes open (max. between 1.5 and 3 at Fz, at separate eyes-open recordings), he showed a high theta/beta ratio with eyes closed (max. 6.5 at Cz). His theta had a dominant rhythm of 6 Hz with a highest amplitude at Cz. The participant had a jet lag because he travelled from a 7-hour distant time zone area two dyas before, and reported feeling sleepy during the eyes-closed EEG recording, so I initially explained the abundance of theta waves to drowsiness. However, the eyes-closed recording had concurrent alpha waves (peak frequency 10 Hz) distributed occipitally. Since I am no sleep expert, I shall appreciate any input into differentiating between ADHD and sleep onset theta EEG waves.
Thanks Marius,
you mean diagnosis as usual with interview as per DSM? I always do that, then I administer standardized rating scales for parents, teachers, and adolescents, then I give full neuropsychological battery incuding continuous performance test, and if still in doubt I record EEG. My question refers to many cases like this, where I have doubts based on diagnosis as usual.
Hello Efthymios,
Do you have seen the data with the laplacian montage ?
Do you have compared the data with a database ? (looking only the theta rhythm for example, without paying attention to the theta/beta ratio. Maybe the power of the beta frequencies is different in the EO and EC condition ?).
Regarding the attention disorder, in the "theta AD(H)D profile", the theta rhythm is supposed to increased in EO condition as well as EC. Usually patients complain about attention problems while they are working (so when the brain is in an EO state).
I will take the jet lag-state of this patient seriously in the interpretation of the data.
The alpha waves are only in occipital or in the parietal electrodes as well (LinkEar and Laplacian) ?
I have had some patients falling asleep at the end of the EC-EEG recording. It's clear some slow waves appear. So I cannot take in account the last minutes of my raw data.
Hope my answer will help you
Regards,
Nadia
Hello Efthymios,
A midline central theta rhythm 6 to 7 Hz occurs episodically in bursts that have duration of 4 to 20sec. It occurs only in the awake state, and is not related to drowsiness. Wesmoreland & Klass (1986) reports this rhythm highly correlates with epilepsy, however about 25% of persons who show this pattern have other disorders, including mental fatigue. Differential diagnosis required with the midline frontal theta rhythm which may occur in adults during mental tasks.
References:
1. Westmoreland BF, Klass DW. Midline theta rhythm. Arch Neurol. 1986 Feb;43(2):139-41.
2. Zhang C, Yu X, Yang Y, Xu L. Phase Synchronization and Spectral Coherence Analysis of EEG Activity During Mental Fatigue. Clin EEG Neurosci. 2014 Oct;45(4):249-256. When the mental fatigue level increases, the interhemispheric theta are enhanced in the frontal region and C3-Cz electrode pair, and the intrahemispheric theta are heightened at frontal-central middle electrode pairs.
3. Lee SM, Jang KI, Chae JH. Electroencephalographic Correlates of Suicidal Ideation in the Theta Band. Clin EEG Neurosci. 2017 Sep;48(5):316-321. EEG activity in theta band in F3, Fz, FCz, and Cz has clinical potential as a biomarker for preventing suicide.
Kind regards,
Tatyana
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