Biomedical subjects

N B Lasko

Publications and source records attributed to N B Lasko.

27 records · Page 2Linked to original sources

PubMed1996

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.

Adult↗

PubMed1995

Autobiographical memory disturbance in combat-related posttraumatic stress disorder.

Vietnam combat veterans with (n = 19) and without (n = 13) posttraumatic stress disorder (PTSD) participated in an autobiographical memory experiment in which they attempted to retrieve specific personal memories exemplifying traits denoted by positive (e.g. loyal) and negative (e.g. guilty) cue words. Veterans with PTSD exhibited difficulties retrieving specific autobiographical memories, especially in response to positive trait cue words. These deficits were especially pronounced in PTSD Ss who wore Vietnam War regalia (e.g. medals, fatigues) to the laboratory. Regalia-wearing PTSD Ss disproportionately retrieved memories from the Vietnam War, unlike other Ss who retrieved relatively recent memories. Wearing regalia in daily life may be emblematic of psychological fixation to a war fought more than two decades ago. Difficulties remembering one's past may underlie difficulties envisioning one's future, as reflected in the PTSD symptom of 'future foreshortening', and difficulties using memory specifically may also hamper efforts to solve personal problems.

Adult↗

PubMed1995

Physiologic responses to loud tones in Vietnam veterans with posttraumatic stress disorder.

The authors evaluated eyeblink and autonomic components of the acoustic startle response in combat-related posttraumatic stress disorder (PTSD). Thirty-seven Vietnam combat veterans with current PTSD and 19 combat veterans without PTSD were exposed to 15 consecutive 95-dB, 500-ms, 1000-Hz tones with 0-ms rise and fall times, while orbicularis oculi electromyogram, skin conductance, and heart rate responses were measured. PTSD veterans produced larger averaged electromyographic and heart rate responses, and a slower decline in skin conductance responses, across the 15 tone presentations compared to non-PTSD veterans. Results of this study provide laboratory support for an exaggerated startle response in PTSD and replicate and extend previous findings of increased autonomic responses to loud tone stimuli in this disorder.

Acoustic Stimulation↗

PubMed1993

Effects of intranasal vasopressin and oxytocin on physiologic responding during personal combat imagery in Vietnam veterans with posttraumatic stress disorder.

This study measured heart rate, skin conductance, and lateral frontalis electromyographic (EMG) responses in 43 male Vietnam veterans with posttraumatic stress disorder during personal combat imagery. In a double-blind research design, subjects were randomly assigned to receive intranasal arginine vasopressin (20 IU), placebo, or oxytocin (20 IU) an hour before the experiment. The group order of physiologic responding was as predicted: vasopressin > placebo > oxytocin. The most specific effect was exerted by vasopressin on EMG responses. This drug effect was not accounted for by nonspecific changes in responsiveness. Results are consistent with enhancing and inhibiting effects on memory retrieval and conditioned responding of vasopressin and oxytocin, respectively.

Administration, Intranasal↗

PubMed1993

Psychophysiological assessment of posttraumatic stress disorder imagery in World War II and Korean combat veterans.

We assessed the heart rate, skin conductance, and left lateral frontalis electromyographic responses of World War II (WWII) and Korean War male veterans to recollection of their combat experiences by using a script-driven imagery technique previously validated in Vietnam veterans (Pitman et al., 1990; Pitman, Orr, Forgue, de Jong, & Claiborn, 1987). Medication-free subjects were classified on the basis of criteria from the revised third edition of the Diagnostic and Statistical Manual of Mental Disorders into posttraumatic stress disorder (PTSD; n = 8) and non-PTSD (n = 12) groups, which did not differ in overall combat exposure or severity of personal combat events. PTSD subjects' physiological responses during personal combat imagery were markedly larger than those of non-PTSD subjects', even though the self-reported emotional responses of the two groups were comparable. A physiological discriminant function derived from Vietnam veterans (Orr et al., 1990) correctly classified 7 of the 8 PTSD subjects (sensitivity was 88%) and 12 of the 12 non-PTSD subjects (specificity was 100%; p < .001).

Aged↗

PubMed1993

Neurological status of Vietnam veterans with chronic posttraumatic stress disorder.

This study investigated neurological status in 27 medication-free outpatient Vietnam veterans meeting DSM-III-R criteria for posttraumatic stress disorder (PTSD) and 15 non-PTSD combat control subjects, all without alcohol or drug dependence or abuse during the past year. Subjects underwent neurological examination, neuropsychological testing, and sleep-deprived EEG. PTSD subjects showed significantly more neurological soft signs than non-PTSD subjects. Neither substance dependence/abuse nor the more frequent history of developmental problems in PTSD subjects accounted for this difference. There were no significant EEG or neuropsychological testing group differences; however, there were significant correlations between several neuropsychological test scores and total neurological soft signs.

Adult↗

PubMedDate not supplied

Seeking the source of emotional Stroop interference effects in PTSD: a study of P3s to traumatic words.

We investigated the source of emotional Stroop interference effects in posttraumatic stress disorder (PTSD) by measuring reaction times and P3 latencies and amplitudes to personal traumatic, personal positive, and neutral words in a modified Stroop paradigm. Individuals with PTSD were slower to indicate word color, especially for traumatic words, thereby replicating emotional Stroop interference in PTSD. Individuals with PTSD also had significantly reduced and delayed P3 components across word types. Across diagnostic groups, frontal P3 amplitudes were larger to personal positive and traumatic words compared to standard neutral words. However, the absence of Diagnosis x Word Type interactions for P3 measures suggests that individuals with PTSD do not differ from individuals without PTSD in the encoding and recognition of the color of traumatic relative to nontraumatic words, and that Stroop interference does not occur during these early stages of processing.

Adult↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

Five-year follow-up study of eye movement desensitization and reprocessing therapy for combat-related posttraumatic stress disorder.

This study reports the results of a 5-year follow-up evaluation of 13 Vietnam combat veterans with chronic posttraumatic stress disorder (PTSD) who participated in a study of eye movement desensitization and reprocessing (EMDR) therapy previously reported in this journal. Pretreatment and follow-up psychometric outcome measures were compared with those of a demographically matched control group of 14 combat veterans with chronic PTSD who did not receive EMDR. Analysis of variance showed that the modest to moderate therapeutic benefits that were manifest immediately following EMDR were lost at the 5-year follow-up evaluation, and there was an overall worsening of PTSD symptomatology over the 5-year period in both EMDR-treated and nontreated control subjects.

Case-Control Studies↗