Identifying Neurological Changes after Trauma

An experimental clinical trial using a novel digital intervention and EEG measurements to investigate how trauma can change our brains.

  • Organization

    Middlebury College

  • My Role

    Principal Researcher

  • Tasks

    Experimental Design, Data Collection and Analysis (MatLab), Participant Recruitment and Coordination, Literature Review and Poster Presentation

Research Question:

Can we detect trauma from an EEG?

Conclusion:

Yes.

Why does this matter?

Understanding the neurology of trauma means that we can more effectively develop treatments that offer real relief.

Stakeholder

Middlebury College invested significant resources into this project, including providing technical lab space, with hope that it could bolster the existing cannon of trauma research.

Focus of Work

We know that having a history of trauma causes externally noticeable behavioral changes in two categories:

  • Hypoarousal (dissociation, numbing)

  • Hyperarousal (hypervigilance, intrusive thoughts, nightmares)

Hypothesis

Those with a history of trauma might show different electrical patterns than those without trauma, corresponding with these visible behavioral symptoms.

Intervention Design

  • In order to replicate a startle (or fear) reflex, we developed a series of images of varying emotional intensity to be passively presented on a screen

  • We assumed that higher emotional intensity images would trigger a neurological startle response that may differ depending on trauma status.

  • We implemented the intervention in a clinical setting where we could measure brain activity of our participants simultaneously.

  • Post-hoc EEG analysis would show us if brain activity during the intervention was different for those with trauma compared to those without.

Important Controls

To make sure that any effect we found was due to the high emotional intensity images, we included control images that were designed to NOT elicit a startle response.

To make sure that any effect we found was due to a trauma response, we recruited and tested a control group (no trauma history) as well.

Analysis

EEG Analysis

Using MatLab software to measure the EEG startle response and a Chi-Square test to compare the four groups (since our data was non-continuous), we discovered that only the trauma group showed a diminished P300 brain wave after viewing startle triggers (high emotional intensity images).

Findings

Conclusion

Our hypothesis was confirmed.

One of the expected startle-related brain waves was significantly smaller, but only in participants who were diagnosed with trauma, and only after the high emotional intensity images.

Smaller brain waves mean less electrical activity, which may correlate with hypoarousal symptoms like dissociation, numbing, and depression.

Post-hoc tests showed that trauma survivors with smaller startle responses were also likely to have depressive symptoms.

Interpretation

This finding might mean that after we experience trauma, our neurology can shift to soften our responses to startling events.

This could be a protective adaptation. When we experience a fear reflex, it costs the body significantly in terms of stress hormones and reflexive behavior.

A traumatized brain may expect that startling events will happen more often, leading it to reduce the threshold for reactivity to save internal resources.

Depressive symptoms may therefore actually be a clever neurological adaptation to cope with trauma.

Next Steps

  • Symptom Validation

    The Diagnostic and Statistical Manual defined dissociation and numbing as symptoms of PTSD long before we had the tools to confirm the underlying neurology. Now we can see that numbing may be a neurological event caused by diminished brain activity.

  • Treatment Recommendations

    Addressing reduced startle response in both pharmaceutical and psychological treatment of PTSD is crucial. Recovery expectations could include healing hypoarousal symptoms that diminish the startle reflex, with a focus on seeing depression as part of the bigger picture and not a separate illness.

  • Opportunity for Innovation

    A trauma diagnosis is often co-morbid with other mental health disorders, like depression, anxiety, disordered eating, and substance abuse. Developing technology to assess brain activity may provide more accurate diagnosis, more specific treatment, and better outcomes.

Limitations

  • Our novel intervention (passively displaying images with a range of emotional intensity) was developed specifically for our study - wider validation would be helpful to verify it as a true measure of a “startle” trigger.

  • Recruitment for our trauma study in a rural area was difficult. Our sample was small, and our trauma group had varied types of trauma (combat veterans, EMTs, car accident survivors). However, even with our small sample, the effect we found was large enough that we had enough power to draw conclusions with statistical significance.

My Role

As a thesis researcher, this was my capstone project under Dr. Matthew Kimble at Middlebury College. My role included:

  • Developing the study design to further explore existing research around the P300 wave (startle response)

  • Recruiting participants

  • Participating in In-Depth Interviews to determine diagnosis and fit for the study

  • Conducting the EEG intervention protocol

  • Analyzing the results (using MATLab and SPSS)

  • Writing an extensive paper outlining the project and our conclusions

  • Presenting a poster with findings

  • Defending my thesis to a team of tenured professors to confirm qualifications for my degree