Integrative Assessment of Brain Function in Ptsd: Brain Stability and Working Memory

Abstract

Posttraumatic Stress Disorder (PTSD) is characterized by symptoms of hyperarousal, avoidance and intrusive trauma-related memories and deficits in everyday memory and attention. Separate studies in PTSD have found abnormalities in electroencephalogram EEG, in event-related potential (ERP) and behavioral measures of working memory and attention. The present study seeks to determine whether these abnormalities are related and the extent to which they share this relationship with clinical symptoms. EEG data were collected during an eyes-open paradigm and a one-back working memory task. Behavioral and clinical data (CAPS) were also collected. The PTSD group showed signs of altered cortical arousal as indexed by reduced alpha power and an increased theta/alpha ratio, and clinical and physiological measures of arousal were found to be related. The normal relationship between theta power and ERP indices of working memory was not affected in PTSD, with both sets of measures reduced in the disordered group. Medication appeared to underpin a number of abnormal parameters, including P3 amplitude to targets and the accuracy, though not speed, of target detection. The present study helps to overcome a limitation of earlier studies that assess such parameters independently in different groups of patients that vary in factors such as comorbidity, medication status, gender and symptom profile. The present study begins to shed light on the relationship between these measures and suggests that abnormalities in brain working memory may be linked to underlying abnormalities in brain stability.

Reduced prefrontal MEG alpha-band power in mild traumatic brain injury with associated posttraumatic stress disorder symptoms

“…It would follow from this argument that the inverse correlation between PTSD symptom severity and alpha power is a function of the relationship of both to TBI severity (in those whose TBI event meets the criteria for mTBI) and does not reflect a direct causal relationship between the decrease in alpha-band power and PTSD. However, the fact that reduced alpha power has been demonstrated in the setting of primary PTSD in previous studies (JokicBegic, 2003;Veltmeyer, 2006;Huang et al, 2014) and our finding of a correlation between the reduction in prefrontal alpha-band power and the specific PTSD symptom of emotional numbing argue against mTBI severity as the causative factor of two otherwise unrelated outcomes, i.e. the decrease in alpha-band oscillatory activity and the increase in susceptibility to PTSD.…”

“…Six of fifteen patients in Group 1 (40%) were taking medications that exert some pharmacological effect on the central nervous system as compared to nine of seventeen in Group 2 (53%). However, it has previously been demonstrated that there is no significant difference in alpha frequency between "medicated" and "non-medicated" patients with PTSD, although there are differences in power demonstrated at faster frequencies (Veltmeyer et al, 2006). Notably, approximately a third of Group 2 patients were taking Prazosin at the time of the recording.…”

“…Controversies regarding the validity of their results were generated by the non-homogeneous subject populations and nonspecific nature of the results, as it was felt the findings could be attributed to a variety of psychiatric conditions or pharmacological effects (see ϰ Nuwer et al, 2005). Independently, other EEG studies in primary PTSD have reported a widespread reduction in alpha-band power relative to healthy controls (Jokic-Begic, 2003;Veltmeyer, 2006).…”

Altered regional homogeneity in post-traumatic stress disorder: a restingstate functional magnetic resonance imaging study

“…The increased activation in the superior frontal cortex found in the present study might therefore be related to altered processing of negative emotions in PTSD, perhaps underlying the avoidance [43] , hypervigilance and emotional numbness [37] seen in PTSD. Consistent with this, a study of resting-state functional connectivity between the posterior cingulate and other brain regions in a group of acutely traumatized adults found that the degree of connectivity with bilateral anterior cingulate region is positively associated with the severity of PTSD symptoms (i.e., the most severe cases had the greatest coordinated activity between posterior and anterior cingulate) [7] .…”

EEG correlates of the severity of posttraumatic stress symptoms: A systematic review of the dimensional PTSD literature

“…It is possible that mixed-trauma samples prevent significant results from being achieved in the EEG studies. In fact, most of the studies that used a mixedtrauma sample found no significant correlation between EEG parameters and the severity of symptoms-very few exceptions were found (Lobo et al, 2014;Veltmeyer et al, 2009Veltmeyer et al, , 2006.…”