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Biomedical subjects

R A Bryant

Publications and source records attributed to R A Bryant.

At least 37 records · Page 2Linked to original sources
PubMed2000

Coping style and post-traumatic stress disorder following severe traumatic brain injury.

There is increasing evidence that a proportion of severe traumatically brain injured (TBI) patients do suffer post-traumatic stress disorder (PTSD). The aim of this study was to investigate the predictors of PTSD following severe TBI in a sample of 96 patients who sustained a severe TBI, of whom 27% satisfied diagnostic criteria for PTSD. The Post-traumatic Stress Disorder Interview, the Coping Style Questionnaire, and the Functional Assessment Measure was administered to these patients 6 months after hospital discharge. Avoidant coping style, behavioural coping style, and a history of prior unemployment were the significant predictors of PTSD severity. These findings indicate that reduction of PTSD and management of severe TBI may be facilitated by teaching patients more adaptive coping strategies.

Adaptation, Psychological↗
PubMed2000

Memory for acute stress disorder symptoms: a two-year prospective study.

The present study aimed to index the accuracy of memory for acute trauma symptoms by comparing the symptoms reported by motor vehicle accident (MVA) victims within 1 month posttrauma with the recall of these symptoms at 2 years posttrauma. Ninety-two consecutive MVA admissions were assessed for the presence of acute stress disorder (ASD) within 1 month posttrauma. At 2 years posttrauma, 61% (N = 56) of the sample were reassessed for posttraumatic stress disorder (PTSD) and for accuracy of recall of the symptoms reported during the first assessment. At least one of the four ASD diagnostic clusters was recalled inaccurately by 75% of patients. High levels of posttraumatic stress severity and high subjective ratings of injury severity at 2 years posttrauma were associated with errors of addition (i.e., recalling the presence of acute symptoms 2 years posttrauma that were not reported during the first assessment). Low levels of posttraumatic stress severity and low subjective ratings of injury severity at 2 years posttrauma were associated with errors of omission (i.e., omitting to recall acute symptoms 2 years posttrauma that were reported during the first assessment). These results suggest that retrospective reports of acute stress symptoms should be interpreted cautiously because of the influence of current symptoms on recall of acute symptoms.

Accidents, Traffic↗
PubMed2000

Two-year prospective evaluation of the relationship between acute stress disorder and posttraumatic stress disorder following mild traumatic brain injury.

OBJECTIVE: To assess the ability of acute stress disorder to predict posttraumatic stress disorder (PTSD), the relationship between acute stress disorder and PTSD over the 2 years following mild traumatic brain injury was determined. METHOD: Survivors of motor vehicle accidents who sustained mild traumatic brain injuries were assessed for acute stress disorder within 1 month of the trauma (N=79) and for PTSD at 6 months (N=63) and 2 years (N=50) posttrauma. RESULTS: Acute stress disorder was diagnosed in 14% of the patients. Among the patients who participated in all three assessments, 80% of the subjects who met the criteria for acute stress disorder were diagnosed with PTSD at 2 years. Of the total initial group, 73% of those diagnosed with acute stress disorder had PTSD at 2 years. CONCLUSIONS: This study provides further support for the utility of the acute stress disorder diagnosis as a predictor of PTSD but indicates that the predictive power of the diagnostic criteria can be increased by placing greater emphasis on reexperiencing, avoidance, and arousal symptoms.

Accidents, Traffic↗
PubMed2000

Posttraumatic stress disorder after severe traumatic brain injury.

OBJECTIVE: This study indexed the profile of posttraumatic stress disorder (PTSD) after severe traumatic injury to the brain. METHOD: Patients who sustained a severe traumatic brain injury (N=96) were assessed for PTSD 6 months after the injury with the PTSD Interview, a structured clinical interview based on DSM-III-R criteria. RESULTS: PTSD was diagnosed in 26 (27.1%) of the patients. While only 19.2% (N=5) of the patients with PTSD reported intrusive memories of the trauma, 96.2% (N=25) reported emotional reactivity. Intrusive memories, nightmares, and emotional reactivity had very strong positive predictive values for the presence of PTSD. CONCLUSIONS: These findings indicate that PTSD can develop after severe traumatic brain injury. The predominance of emotional reactivity and the relative absence of traumatic memories in patients with PTSD who suffered impaired consciousness during trauma suggest that traumatic experiences can mediate PTSD at an implicit level.

Adolescent↗
PubMed2000

Acute Stress Disorder Scale: a self-report measure of acute stress disorder.

The Acute Stress Disorder Scale (ASDS) is a self-report inventory that (a) indexes acute stress disorder (ASD) and (b) predicts posttraumatic stress disorder (PTSD). The ASDS is a 19-item inventory that is based on Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV, American Psychiatric Association, 1994) criteria. The ASDS possessed good sensitivity (95%) and specificity (83%) for identifying ASD against the ASD Interview on 99 civilian trauma survivors. Test-retest reliability of the ASDS scores between 2 and 7 days was strong (r = .94). The ASDS predicted 91% of bushfire survivors who developed PTSD and 93% of those who did not; one third of those identified by the ASDS as being at risk did not develop PTSD, however. The ASDS shows promise as a screening instrument to identify acutely traumatized individuals who warrant more thorough assessment for risk of PTSD.

Acute Disease↗
PubMed2000

A prospective study of psychophysiological arousal, acute stress disorder, and posttraumatic stress disorder.

This study investigated the role of acute arousal in the development of posttraumatic stress disorder (PTSD). Hospitalized motor-vehicle-accident survivors (n = 146) were assessed for acute stress disorder (ASD) within 1 month of the trauma and were reassessed (n = 113) for PTSD 6 months posttrauma. Heart rate (HR) and blood pressure (BP) were assessed on the day of hospital discharge. Participants with subclinical ASD had higher HR than those with ASD and no ASD. Participants who developed PTSD had higher HR in the acute posttrauma phase than those without PTSD. Diagnosis of ASD and resting HR accounted for 36% of the variance of the number of PTSD symptoms. A formula composed of a diagnosis of ASD or a resting HR of > 90 beats per minute possessed strong sensitivity (88%) and specificity (85%) in predicting PTSD. These findings are discussed in terms of acute arousal and longer term adaptation to trauma.

Accidents, Traffic↗
PubMed1999

Cathepsin S controls the trafficking and maturation of MHC class II molecules in dendritic cells.

Before a class II molecule can be loaded with antigenic material and reach the surface to engage CD4+ T cells, its chaperone, the class II-associated invariant chain (Ii), is degraded in a stepwise fashion by proteases in endocytic compartments. We have dissected the role of cathepsin S (CatS) in the trafficking and maturation of class II molecules by combining the use of dendritic cells (DC) from CatS(-/-) mice with a new active site-directed probe for direct visualization of active CatS. Our data demonstrate that CatS is active along the entire endocytic route, and that cleavage of the lysosomal sorting signal of Ii by CatS can occur there in mature DC. Genetic disruption of CatS dramatically reduces the flow of class II molecules to the cell surface. In CatS(-/-) DC, the bulk of major histocompatibility complex (MHC) class II molecules is retained in late endocytic compartments, although paradoxically, surface expression of class II is largely unaffected. The greatly diminished but continuous flow of class II molecules to the cell surface, in conjunction with their long half-life, can account for the latter observation. We conclude that in DC, CatS is a major determinant in the regulation of intracellular trafficking of MHC class II molecules.

Animals↗
PubMed1999

Predictors of acute stress following motor vehicle accidents.

The aim of this study was to investigate the predictors of acute stress following motor vehicle accidents (MVA). Sixty-two consecutive adult admissions to a hospital were assessed between two days and four weeks following a MVA. Participants were assessed for acute stress disorder (ASD) with a structured clinical interview and administered the Beck Depression Inventory (BDI), Coping Style Questionnaire, Dissociative Experiences Scale, and the Eysenck Personality Inventory. The prevalences of full and sub-syndromal ASD were 16.1% and 14.5%, respectively. BDI, history of psychiatric treatment, history of posttraumatic stress disorder (PTSD), and history of previous MVA accounted for 61% of the variance of acute stress severity. The findings indicate that predictors of acute stress severity are comparable to the predictors of PTSD and highlight the possibility of identifying those who may benefit from early treatment.

Accidents, Traffic↗
PubMed1999

Dissociative symptoms in acute stress disorder.

This study provides a profile of symptoms, and particularly dissociative symptoms, in the diagnosis of acute stress disorder (ASD) following motor vehicle accidents (MVAs). Consecutive adult non-brain-injured admissions to a major trauma hospital (N = 92) were assessed between 2 days and 4 weeks following an MVA. Presence of ASD was determined by a structured clinical interview. The occurrence of full and subsyndromal ASD was approximately 13% and 21%, respectively. The majority of those who met criteria for subsyndromal ASD did not meet the ASD criteria for dissociation. At least 80% of individuals who reported derealization also reported reduced awareness and depersonalization. This significant overlap between dissociative symptoms questions the discriminatory power and conceptual independence of the dissociative criteria. These findings suggest the need for a more refined conceptual and operational understanding of dissociative symptoms in the acute trauma stage.

Accidents, Traffic↗
PubMed1999

The relationship between acute stress disorder and posttraumatic stress disorder: a 2-year prospective evaluation.

Previous research established that 78% of a sample of motor vehicle accident survivors initially diagnosed with acute stress disorder (ASD) were subsequently diagnosed with posttraumatic stress disorder (PTSD) at 6 months posttrauma. Although the previous study provided initial evidence for the utility of the ASD diagnosis, the relationship between ASD and PTSD was assessed over a relatively short period. The present study reassessed that original sample 2 years following the trauma to establish the longer term relationship between ASD and PTSD. ASD was diagnosed in 13% of participants, and 21% were diagnosed with subsyndromal ASD. In terms of participants who participated in all 3 assessments, 63% who met the criteria for ASD, 70% who met the criteria for subsyndromal ASD, and 13% who did not meet the criteria for ASD were diagnosed with PTSD at 2 years posttrauma. These findings indicate the importance of considering multiple pathways to the development of PTSD.

Acute Disease↗
PubMed1999

Posthypnotic amnesia for material learned before hypnosis.

The impact of a suggestion for posthypnotic amnesia on material learned either before or during hypnosis was investigated across 2 experiments. In Experiment 1, very high, high, and low hypnotizable participants learned a word list either before or immediately after a hypnotic induction. During hypnosis, participants were given a suggestion for posthypnotic amnesia for the word list. After hypnosis, they were tested on recall, word-fragment, and word-recognition tasks. Experiment 2 replicated and extended Experiment 1 through application of the real-simulating paradigm. Across the 2 experiments, there was no difference in the performance of participants who learned the word list either before or during hypnosis. Although amnesia on direct memory measures was associated with high hypnotizability (Experiment 1), an explanation based on demand characteristics could not be excluded (Experiment 2). The implications of these findings for the use of post-hypnotic amnesia as a laboratory analog of disorders of autobiographical memory are discussed.

Adult↗
PubMed1999

Eliciting autobiographical pseudomemories: the relevance of hypnosis, hypnotizability, and attributions.

The authors investigated the roles of hypnosis, hypnotizability, and attributions in autobiographical pseudomemories. Experiment 1 administered a suggestion for recall of their second birthday to hypnotized high and low hypnotizable participants and nonhypnotized, high hypnotizable participants; Experiment 2 administered a similar suggestion to real and simulating participants. Recall was tested during hypnosis, after hypnosis, and after a challenge procedure. In Experiment 1, more highs than lows reported a memory during hypnosis; however, following the challenge, half the walking highs but none of the hypnosis highs retracted their memory. Notably, highs attributed their memories to reconstructions based on other birthdays. In Experiment 2, whereas an equal number of reals and simulators reported a memory of their second birthday during hypnosis and then retracted following the challenge, they made different attributions about their memories. These findings highlight the value of a closer investigation of attributional processes that reconcile believed-in autobiographical memories with conflicting evidence.

Adult↗
PubMed1999

The influence of traumatic brain injury on acute stress disorder and post-traumatic stress disorder following motor vehicle accidents.

This study compared the acute stress disorder and post-traumatic stress disorder (PTSD) symptom profiles in motor vehicle accident survivors who sustained a mild traumatic brain injury (MTBI) or no TBI. Consecutive adult patients who sustained a MTBI (n = 79) and no TBI (n = 92) were assessed for acute stress disorder within 1 month of their trauma and reassessed for PTSD (MTBI: n = 63; non-TBI; n = 72) 6-months post-trauma. Comparable rates of acute stress disorder and PTSD were reported in MTBI and non-TBI patients. Intrusive memories and fear and helplessness in response to the trauma were reported less frequently by MTBI than non-TBI patients at the acute phase. Six-months post-trauma fewer MTBI patients than non-TBI reported fear and helplessness in response to the trauma. These findings suggest that, whereas impaired consciousness at the time of a trauma may reduce the frequency of traumatic memories in the initial month post-trauma, MTBI does not result in a different profile of longer-term PTSD.

Accidents, Traffic↗
PubMed1999

Interaction of posttraumatic stress disorder and chronic pain following traumatic brain injury.

OBJECTIVE: To investigate the association between posttraumatic stress disorder (PTSD) and chronic pain in patients who had sustained a severe traumatic brain injury (TBI). DESIGN: Correlational relationships between pain variables and PTSD measures were examined in a cohort study. SETTING: An adult tertiary care center brain injury clinic. PATIENTS: Ninety-six persons with severe TBI. OUTCOME MEASURES: The Posttraumatic Stress Disorder Interview (PTSD-I), a modified McGill Pain Questionnaire, the Beck Depression Inventory (BDI), the General Health Questionnaire (GHQ), the Community Integration Questionnaire (CIQ), the Satisfaction with Life Scale (SWL), and the Coping Style Questionnaire (CSQ). RESULTS: More persons with chronic pain reported PTSD than did those without pain. The relationship between pain severity and depression, functional adjustment, and satisfaction with life was mediated by severity of PTSD. Pain severity was significantly associated with an avoidant coping style. CONCLUSIONS: Effective rehabilitation of persons with chronic pain following severe TBI should recognize the role of posttraumatic stress in the maintenance of dysfunctional reactions. Specific interventions that address adaptive coping mechanisms to reduce PTSD may enhance rehabilitation for persons with TBI who suffer chronic pain.

Adaptation, Psychological↗
PubMed1999

Postconcussive symptoms and posttraumatic stress disorder after mild traumatic brain injury.

Postconcussive symptoms after mild traumatic brain injury (MTBI) may be exacerbated by anxiety associated with posttraumatic stress. The aim of this study was to investigate the relationship between postconcussive symptoms and posttraumatic stress disorder (PTSD) in an MTBI population. Survivors of motor vehicle accidents who either sustained an MTBI (N = 46) or no TBI (N = 59) were assessed 6 months posttrauma for PTSD and postconcussive symptoms. Postconcussive symptoms were more evident in MTBI patients with PTSD than those without PTSD, and in MTBI patients than non-TBI patients. Further, postconcussive symptoms were significantly correlated with PTSD symptoms. These findings indicate that postconcussive symptoms may be mediated by an interaction of neurological and psychological factors after MTBI.

Accidents, Traffic↗
PubMed1999

Proteases involved in MHC class II antigen presentation.

Major histocompatibility complex class II antigen presentation requires the participation of lysosomal proteases in two convergent processes. First, the antigens endocytosed by the antigen-presenting cells must be broken down into antigenic peptides. Second, class II molecules are synthesized with their peptide-binding site blocked by invariant chain (Ii), and they acquire the capacity to bind antigens only after Ii has been degraded in the compartments where peptides reside. The study of genetically modified mice deficient in single lysosomal proteases has allowed us to determine their role in these processes. Cathepsins (Cat) B and D, previously considered major players in MHC class II antigen presentation, are dispensable for degradation of Ii and for generation of several antigenic determinants. By contrast, Cat S plays an essential role in removal of Ii in B cells and dendritic cells, whereas Cat L apparently does so in thymic epithelial cells. Accordingly, the absence of Cat S and L have major consequences for the onset of humoral immune responses and for T-cell selection, respectively. It is likely that other as yet uncharacterized lysosomal enzymes also play a role in Ii degradation and in generation of antigenic determinants. Experiments involving drugs that interfere with protein traffic suggest that more than one mechanism for Ii removal, probably involving different proteases, can co-exist in the same antigen-presenting cell. These findings may allow the development of protease inhibitors with possible therapeutic applications.

Animals↗