The prospective course of postconcussion syndrome: the role of mild traumatic brain injury.

OBJECTIVE: To investigate whether postconcussion syndrome (PCS) represents long-term sequelae associated with mild traumatic brain injury (mTBI). METHODS: Prospective consecutive admissions to a Level 1 trauma hospital were assessed a mean 4.9 days and again 106.2 days post-injury. The final sample comprised 62 mTBI and 58 nonbrain injured trauma controls (TC). Change or lack of change in individual PCS-like symptoms and PCS was examined. Multilevel logistic regression was used to analyze whether mTBI predicts 3-month PCS (Time 2; T2); whether predictors of PCS (within 14 days of injury, Time 1; T1) predict 3-month PCS, and how change in these predictors from T1 to T2 were associated with change in PCS status. Variables included demographic, injury-related, financial incentives, neuropsychological, and psychiatric disorder. RESULTS: MTBI did not predict PCS. PCS was comparable (T1: mTBI: 40.3%, TC: 50.0%; T2: mTBI: 46.8%, TC: 48.3%). At T2, 38.6% were new cases of PCS; between 30.8% and 86.2% reported either a new or more frequent symptom. A pre-injury depressive or anxiety disorder (OR = 2.99, 95% CI [1.38, 6.45]), and acute posttraumatic stress (OR = 1.05, 95% CI [1.00, 1.00]) were early markers of PCS, regardless of mTBI. An interaction between time and posttraumatic stress disorder (PTSD) suggested the relationship between the severity of PTSD symptoms and PCS strengthened over time (OR = 2.66, 95% CI [1.08, 6.55]). Pain was related to PCS. Females were more likely than males to have PCS. CONCLUSION: The data suggest the phenomenon of PCS in trauma patients does not show an association with mTBI.

Applicability of neural reserve theory in mild traumatic brain injury.

OBJECTIVE: The aim of the current study was to examine whether neural reserve influenced the duration of post-traumatic amnesia (PTA) following mild traumatic brain injury (MTBI). METHOD: The relationship between duration of PTA and both IQ and education was examined in a group of 59 MTBI patients. In addition, the effects of factors that could potentially diminish neural reserve, namely pre-injury hazardous alcohol consumption, pre-injury marijuana use, previous neurological damage, age and post-injury emotional distress on PTA duration were analysed. RESULTS: Significant, negative associations between PTA duration and both IQ and education were revealed. None of the other variables that were examined were significantly related to PTA duration. CONCLUSION: The findings were interpreted as providing preliminary evidence to suggest that reference to neural reserve may help explain between-subject variability in acute response to MTBI.

The relationship of psychological and cognitive factors and opioids in the development of the postconcussion syndrome in general trauma patients with mild traumatic brain injury.

The relationship of psychological and cognitive factors in the development of the postconcussion syndrome (PCS) following mild uncomplicated traumatic brain injury (mTBI) has received little study. This may be because of the widely held belief that neurological factors are the cause of early PCS symptoms, whereas psychological factors are responsible for enduring symptoms. To further understand these relationships, the association between PCS and neuropsychological and psychological outcome was investigated in 122 general trauma patients, many of whom had orthopedic injuries, around 5 days following mTBI. Apart from verbal fluency, participants with a PCS did not differ in their performances on neuropsychological measures compared to those without a PCS. Individuals with a PCS reported significantly more psychological symptoms. Large effect sizes present on the psychological measures showed that the difference between participants with a PCS and without was greater on psychological than on neuropsychological measures. Analyses also revealed a relationship between opioid analgesia and depression, anxiety and stress, and opioids and reduced learning. The results suggest that psychological factors are present much earlier than has previously been considered in the development of the PCS.

Elevated resting heart rate as a predictor of posttraumatic stress disorder after severe traumatic brain injury.

OBJECTIVE: This study indexed the relationship between resting heart rates (HRs) after injury and subsequent posttraumatic stress disorder (PTSD) in patients who sustained severe traumatic brain injury (TBI). METHODS: Patients who sustained a severe TBI (N = 68) had their resting HR assessed 1 week and 1 month after injury, and they were assessed for PTSD 6 months after injury with the PTSD Interview, a structured clinical interview based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 3rd Edition, Revised. RESULTS: PTSD was diagnosed in 23% of patients. PTSD participants had higher HRs at 1 week but not at 1 month after trauma than non-PTSD participants. This difference remained significant when the effect of posttraumatic amnesia was controlled, but it was not significant when the effect of Glasgow Coma Scale was controlled. CONCLUSION: These findings accord with the proposal that fear conditioning can occur outside the level of awareness and contribute to PTSD development.

Pharmacological management of Dysautonomia following traumatic brain injury.

PRIMARY OBJECTIVE: To document and critically evaluate the likely effectiveness of pharmacological treatments used in a sample of patients with Dysautonomia and to link these findings to previously published literature. RESEARCH DESIGN: Retrospective case control chart review. METHODS AND PROCEDURES: Data were collected on age, sex and GCS matched subjects with and without Dysautonomia (35 cases and 35 controls). Data included demographic and injury details, physiological parameters, medication usage, clinical progress and rehabilitation outcome. Descriptive analyses were undertaken to characterize the timing and frequency of CNS active medications. MAIN OUTCOMES AND RESULTS: Dysautonomic patients were significantly more likely to receive neurologically active medications. A wide variety of drugs were utilised with the most frequent being morphine/midazolam and chlorpromazine. Cessation of morphine/midazolam produced significant increases in heart rate and respiratory rate but not temperature. Chlorpromazine may have modified respiratory rate responses, but not temperature or heart rate. CONCLUSIONS: The features of Dysautonomia are similar to a number of conditions treated as medical emergencies. Despite this, no definitive treatment paradigm exists. The best available evidence is for morphine (especially intravenously), benzodiazepines, propanolol, bromocriptine and possibly intrathecal baclofen. Barriers to improving management include the lack of a standardized nomenclature, formal definition or accepted diagnostic test. Future research needs to be conducted to improve understanding of Dysautonomia with a view to minimizing disability.

Sex differences in injury severity and outcome measures after traumatic brain injury.

OBJECTIVE: To investigate the effect of a patient's sex on various measures of injury severity and outcome after rehabilitation in a matched sample of patients with traumatic brain injury (TBI). DESIGN: Retrospective data were retrieved from a database that contains information routinely collected on all patients admitted for inpatient rehabilitation. SETTING: Inpatient rehabilitation unit of major teaching hospital in Australia. PARTICIPANTS: Fifty-four women with TBI after a motor vehicle crash (MVC) were identified from the Brain Injury Rehabilitation Database. An equal number of men were then matched for age and years of education. All subjects met the study admission criteria of having being involved in a high-speed MVC. Exclusion criteria included history of a previous head injury, chronic amnesia, psychiatric disturbance, and significant alcohol and/or substance abuse. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Differences, by sex, in patient scores on measures of injury severity and outcome after TBI. RESULTS: Men had significantly greater levels of injury severity as indicated by the Glasgow Coma Scale scores (U=994.0, P=.002) and length of posttraumatic amnesia (U=880.0, P=.016) when compared with women. No significant sex differences existed in the outcome measures or in injuries not associated with the central nervous system. CONCLUSIONS: Few investigations exist on the effect of patient sex on measures of injury severity and outcome after a TBI. In the present study, men's levels of injury severity were greater than women's despite the same admission criteria (high-speed MVC) being applied to both sexes.