Can an EEG Test Diagnose Depression?

What is an EEG?

Electroencephalogram (EEG) is a test used to record electrical activity from the brain’s cortex. Through electrodes placed on different regions of the scalp, it records changes in voltage as ions spontaneously move across the membrane of the neurons.

Similar to EEG, evoked potentials are also recordings of the brain’s electrical activity. However, evoked potentials are produced by a stimulus (e.g. visual or auditory stimuli) instead of the spontaneous recording obtained through EEG.

Event related potentials (ERP) hold some promise in neuropsychiatric research but have little clinical relevance. These recordings, even smaller than EEG and evoked potential waveforms, are time-locked waveforms following a stimulus and its corresponding neurobehavioral response.

Can an EEG Test Find Depression?

In general, all of these waveforms offer non-specific findings as it relates to psychological conditions. For example, a depressed patient quite frankly will have normal EEG, evoked potentials, and event related potentials if no confounding structural lesion exists.

In contrast, there is anecdotal evidence that patients with depression can have certain timed recordings with lower amplitude (i.e. P300 waveform). Emotions originate from deeper, more primitive areas of the brain, such as the limbic system.

However, they reach our conscious through the cortex. Therefore, theoretically, scalp electrodes can record waveforms related to feelings.

But since these recordings are generated through signal averaging, electrodes placed closer to the structures where emotions are generated may be offer more sensitive and specific recordings.

About Dr. Dee

Decontee Jimmeh, MD is a board certified neurologist with fellowship training in neurophysiology from the University of Alabama School of Medicine. Currently, she is in private practice in Birmingham, Al at Norwood Clinic associated with Brookwood Medical Center

The Neurologic Effects of Tear Gas Exposure

In recent days we've all seen the news coverage of the Ferguson, Missouri shooting and riots. The eyes of the world are watching the events as they happen.

It breaks my heart to know a young man was gunned down. What's worse is people have taken to the streets in protest, but that protest has turned into more violence. To control the crowd the police have resorted to using tear gas.

I will not comment on how absurd I think this behavior is (on both sides), but I offer my medical observations regarding the physical affects of the tear gas and what to do in case of exposure.

What is Tear Gas?

Tear gas and other lacrimating agents have been used since the early 1900s as a means of crowd control. Some examples include xylyl bromide, dibenzoxazepine (CR gas), 2-chlorobenzalmalononitrile (CS gas), Phenacyl chloride (CN gas), syn-propanethial-S-oxide, and pepper spray.

How Does Tear Gas Affect the Body?

These compounds are absorbed by the mucous membranes of the eyes, nose, mouth, and lungs. In the eye, the gas stimulates corneal nerves, which cause profuse tearing and eye muscle cramping as a protective measure to provoke eye closure.

Other effects observed in victims of tear gas exposure include burning of the mouth and throat, difficulty breathing, headache, dizziness, and even blindness. While there is no definite effective antidote, there are many anecdotal reports of substances like milk helping to ease the effects of tear gas. This is presumably due to the neutralizing, antacid properties of milk.

 If exposed to tear gas, follow these instructions: 

• Do not panic 
• Avoid the path of the dispensing grenade canister. It is usually hot to touch and near the greatest concentration of gas. 
• If no mask is available, use cloth to cover your face until you can reach higher ground. You may have to cover your face with the shirt you are wearing. 
• Remove contact lenses and flush eyes profusely with water (once in a clear area) until pain abates 
• You may need supplemental oxygen if breathing problems exist. 
• Seek medical attention urgently for further monitoring and treatment

Decontee "Dr. Dee" Jimmeh, MD Talks Foot Nerve Pain

It was a pleasure to answer questions about foot nerve pain during the Fox 6 Birmingham Ask the Doctor segment recently. Here is the video replay.

If you have any questions leave them in the comments below.