Tamara V. Gurvits

Magnetic resonance imaging study of hippocampal volume in chronic, combat-related posttraumatic stress disorder

This study used quantitative volumetric magnetic resonance imaging techniques to explore the neuroanatomic correlates of chronic, combat-related posttraumatic stress disorder (PTSD) in seven Vietnam veterans with PTSD compared with seven nonPTSD combat veterans and eight normal nonveterans. Both left and right hippocampi were significantly smaller in the PTSD subjects compared to the Combat Control and Normal subjects, even after adjusting for age, whole brain volume, and lifetime alcohol consumption. There were no statistically significant group differences in intracranial cavity, whole brain, ventricles, ventricle:brain ratio, or amygdala. Subarachnoidal cerebrospinal fluid was increased in both veteran groups. Our finding of decreased hippocampal volume in PTSD subjects is consistent with results of other investigations which utilized only trauma-unexposed control groups. Hippocampal volume was directly correlated with combat exposure, which suggests that traumatic stress may damage the hippocampus. Alternatively, smaller hippocampi volume may be a pre-existing risk factor for combat exposure and/or the development of PTSD upon combat exposure.

Multivariate Assessment of Explicit Memory Function in Combat Veterans with Posttraumatic Stress Disorder

Declarative memory impairment is a frequent complaint of patients suffering from posttraumatic stress disorder (PTSD). We assessed memory, attention, visual spatial skills, and executive function in Vietnam combat veterans with (n = 19) and without (n = 13) PTSD. Although PTSD subjects demonstrated a “generalized impairment” relative to non-PTSD subjects on a majority of tasks, only attention and memory provided unique and independent prediction of PTSD versus non-PTSD status. Our findings suggest that memory functioning represents a neurocognitive domain of specific relevance to the development of PTSD in trauma-exposed individuals, which can be distinguished from generalized attentional impairment as well as the effects of trauma exposure severity, IQ, comorbid depression, history of alcohol use, and history of developmental learning problems.

Neurocognitive function in monozygotic twins discordant for combat exposure : Relationship to posttraumatic stress disorder

Neuropsychological deficits have been reported among trauma survivors with posttraumatic stress disorder (PTSD). It is often assumed that these cognitive difficulties are toxic consequences of trauma exposure. Alternatively, they may reflect preexisting characteristics that contribute to the likelihood of developing PTSD. To address this possibility, the authors evaluated cognitive performance in monozygotic twin pairs who were discordant for combat exposure. Pairs were grouped according to whether the combat-exposed brother developed PTSD. The combat-unexposed cotwins of combat veterans with PTSD largely displayed the same performance as their brothers, which was significantly lower than that of non-PTSD combat veterans and their brothers. The results support the notion that specific domains of cognitive function may serve as premorbid risk or protective factors in PTSD.

Clarifying the Origin of Biological Abnormalities in PTSD Through the Study of Identical Twins Discordant for Combat Exposure

Abstract:  A biological abnormality found to be associated with posttraumatic stress disorder (PTSD) may be, among other things, a pretrauma vulnerability factor, that is, it may have been present prior to the events occurrence and increased the individuals likelihood of developing PTSD upon traumatic exposure. Alternately, it may be an acquired PTSD sign, that is, it may have developed after the traumatic exposure, along with the PTSD. We have studied pairs of Vietnam combat veterans and their noncombat‐exposed, identical twins in an effort to resolve these competing origins. Combat veterans were diagnosed as current PTSD or non‐PTSD (i.e., never had). Average heart rate responses (HRRs) to a series of sudden, loud‐tone presentations were larger in Vietnam combat veteran twins with PTSD, but these larger responses were not shared by their noncombat‐exposed cotwins, whose responses were similar to those of the non‐PTSD combat veterans and their noncombat‐exposed cotwins. These results suggest that larger HRRs to sudden, loud tones represent an acquired sign of PTSD. In contrast, increased neurological soft signs (NSSs), diminished hippocampal volume, and presence of abnormal cavum septum pellucidum (CSP) were found in Vietnam combat veteran twins with PTSD and their “high‐risk,” unexposed cotwins compared to Vietnam combat veteran twins without PTSD and their “low‐risk,” unexposed cotwins. These results support the conclusion that the latter abnormalities represent antecedent, familial vulnerability factors for developing chronic PTSD upon exposure to a traumatic event.

Aggression and its correlates in Vietnam veterans with and without chronic posttraumatic stress disorder

This study measured self-reported aggression, hostility, and anger in Vietnam combat veterans with (n = 27) and without (n = 15) posttraumatic stress disorder (PTSD). On the Buss-Durkee Hostility Inventory, Past Feelings and Acts of Violence Scale, Episodic Dyscontrol Scale, and State-Trait Anger Expression Inventory (STAXI), PTSD subjects scored significantly higher than non-PTSD subjects, whose scores fell in the range reported for normative, noncombat populations. The PTSD versus non-PTSD group differences were not explained by combat exposure, which did not correlate significantly with the psychometric aggression measures. These findings suggest that increased aggression in war veterans is more appropriately regarded as a property of PTSD, rather than a direct consequence of military combat. The association between compromised neurologic and neuropsychologic status and the psychometric measures was modest and explained little of the group differences.

Configural Cue Performance in Identical Twins Discordant for Posttraumatic Stress Disorder: Theoretical Implications for the Role of Hippocampal Function

BACKGROUND A significant subgroup of individuals with posttraumatic stress disorder (PTSD) exhibits chronic, unremitting symptomatology that has also been associated with smaller hippocampal volume. The hippocampus plays a significant role in configural processing of contextual cues that facilitates context-appropriate extinction of conditioned fear. We test the hypothesis that hippocampus-based configural processing deficits are a pre-existing vulnerability factor for unremitting forms of PTSD. METHODS Participants included male monozygotic twin pairs who were discordant for combat trauma. In 18 twin pairs the combat-exposed brother developed unremitting PTSD, whereas in 23 pairs the combat-exposed brother never developed PTSD. Participants were compared in the capacity to solve allocentric spatial processing tasks, and this performance was examined for its relationship to the severity of PTSD symptomatology and hippocampal volume. RESULTS Although not completely differentiated from overall IQ, PTSD combat veterans demonstrated significantly impaired performance in configural processing relative to non-PTSD combat veterans. Despite having neither combat-exposure nor PTSD, the unexposed co-twins of combat veterans with PTSD displayed the same decrements as their brothers. Deficits were significantly related to PTSD severity and hippocampal volume. CONCLUSIONS The current study provides the first evidence that the relevance of the hippocampus in PTSD might be related to pre-existing configural cue processing deficits that predispose individuals to develop unremitting forms of the disorder.

Performance on visuospatial copying tasks in individuals with chronic posttraumatic stress disorder

The ability to copy figures was evaluated in 41 subjects with chronic posttraumatic stress disorder (PTSD) and 27 trauma-exposed, non-PTSD comparison subjects. Individuals with PTSD demonstrated significantly impaired performance. However, after adjusting for pre-trauma variables, there was only a marginally significant association between figure-copying performance and PTSD. These findings are consistent with pre-trauma visual-spatial impairment as being among the risk factors for chronic PTSD.

Neurological Status of Combat Veterans and Adult Survivors of Sexual Abuse PTSD

We found higher levels of positive soft neurological signs in PTSD participants than in participants who also experienced similar trauma but did not develop PTSD. This finding was replicated in two samples, that is, Vietnam combat veterans and adult female survivors of childhood sexual abuse, despite differences in gender, age, nature of trauma, and period of life when the trauma occurred. Past developmental history of participants and a substance abuse history of first-degree relatives also differentiated PTSD from non-PTSD groups in both combat and sexual abuse samples. Evidence for neurological impairment and compromised developmental history raises the possibility of pretrauma impairment as a risk factor for the development of PTSD.

Absence of selected neurological soft signs in Vietnam nurse veterans with post-traumatic stress disorder

This study examined eight neurological soft signs (NSSs), which had previously proved successful in discriminating medication-free post-traumatic stress disorder (PTSD) from non-PTSD combat veterans and sexually abused women, in 82 unmedicated female nurse Vietnam veterans, 32 with and 50 without PTSD. The increased NSSs observed in the previously studied PTSD samples were not found in the nurses with PTSD. The results fail to support the hypothesis that the stress of a traumatic event and/or resultant PTSD damages the nervous system.

Pilot Study of Neurological Soft Signs and Depressive and Postconcussive Symptoms During Recovery From Mild Traumatic Brain Injury (mTBI)

Neurological soft signs (NSSs) tap into a variety of perceptual, motor, and cognitive functions. The authors administered a battery of NSSs serially to a group of 14 pilot patients recruited from an emergency room after they experienced a mild traumatic brain injury. Patients were seen within 96 hours after injury, and again 30 and 90 days later. Measures of balance, mood, and postconcussive symptoms and impairment were also obtained. NSSs and balance improved across visits. Across visits, NSSs and balance were not significantly associated with any postconcussive outcome measures, although depressive symptoms were. Initial neurological impairment appeared to predict subsequent residual postconcussive symptoms and impairment, but this result requires replication.