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arbias Ltd in conjunction with Latrobe University were contracted by Corrections Victoria to undertake the project titled ―Acquired Brain Injury: Screening, Identification and Validation in the Victorian Correctional System. Ethics approval was granted by La Trobe University (Application No: 08-030) and the Department of Justice Human Research Ethics Committee (Approval: CF/07/6072).
There were two main aims of the study. The first aim was to test the efficiency and veracity of a three-stage process for screening and identification of prisoners entering the Victorian correctional system who may have an acquired brain injury (ABI). The second aim of the study was to provide indicative data on the prevalence of ABI within the Victorian correctional system. The study used a three-tiered approach of initial screening, clinical interview and neuropsychological assessment to provide an indication of the potential prevalence rate of prisoners with an ABI within the Victorian prison system, as well as the nature and aetiology of the brain injury.
In Stage 1, 110 adult male prisoners and 86 female prisoners consented to participate in the study. Participants were recruited from sentenced prisoners only. Sixty-four per cent of male prisoners endorsed at least one ABI risk factor, whilst 73% of female prisoners endorsed at least one ABI risk factor during screening for ABI.
The most commonly endorsed risk factors for male prisoners were drug use (61%), hypoxic brain injury (47% – overdose and suicide attempt), traumatic brain injury (TBI) (29%) and alcohol use (25%). The most commonly endorsed risk factors for female prisoners were drug use (62%), hypoxic brain injury (51% – overdose and suicide attempt), TBI (29%) and alcohol (15%). Comparing male and female prisoners, female prisoners were more likely to endorse drug use, whilst males were more likely to endorse alcohol use.
Stage Two of the studies involved clinical interviews being conducted by staff employed by arbias Ltd. 90 male prisoners and 53 female prisoners continued to the clinical interview stage. The clinical interview involved taking a comprehensive background history, as well as further information regarding ABI risk factors. The male and female prisoners differed from the general population on a number of demographic variables including education, employment, accommodation, mental health history, substance use and offending behaviour:
In stage 3, 74 male prisoners and 42 female prisoners participated in a full neuropsychological assessment. The diagnosis of an ABI was based on independent evaluation of the evidence by two clinical neuropsychologists at arbias Ltd.
This evidence included the profile of cognitive strengths and weaknesses on formal testing, behavioural observations during the assessment and consideration of background history including ABI risk factors. ABI was not diagnosed when the cognitive deficits could be wholly explained by factors such as medication side-effects, physical problems, emotional disturbance, the person’s intellectual background, and limited history of education.
Males and females were found to have different neuropsychological profiles with significant differences found on tests of perceptual and spatial ability, complex vision memory and spatial working memory. As a result of the finding of different male and female profiles, it was decided to analyse the male and female data separately.
Male and female prisoners who were diagnosed as not having ABI performed overall in the average range in all neuropsychological tests and cognitive categories.
Overall, male and female prisoners with an ABI produced significantly different cognitive profiles.
Females tended to present with more impairments in spatial abilities, complex attention and working memory, whilst male prisoners had more wide spread and generalised impairments in all areas, apart from basic processing speed and the basic perceptual abilities.
It is likely the females’ cognitive profile is the result of substance use, in particular, benzodiazepine use. In contrast, the males’ impairment profile more resembles that seen in alcohol related brain injury and traumatic brain injury.
Formal analysis of the sensitivity of the screening tool with regard to identifying a potential ABI indicated that the screening tool was able to identify potential ABI. There were no false negatives in the female participants. By contrast, there was a false negative rate of almost one quarter in the male sample, indicating that some male prisoners were still being missed at the screening stage. It was noted that new learning and memory problems were the most significantly impaired cognitive skill in males (moderate to severe impairment), and this is likely to have made their history somewhat unreliable. Thus they tended to under-report risk factors on screening assessment. This highlights the importance of not relying solely on the screening, as well as the usefulness of clinical interview and formal neuropsychological assessment.
The current research has found that the prevalence of ABI in the Victorian Correctional System is high, with 42% of males and 33% of females found to have evidence of an ABI following formal neuropsychological assessment. This indicates that persons with an ABI are a significant proportion of both male and female prisoners and are a group that requires particular attention.
Unexpectedly, male and female prisoners produced different profiles of cognitive impairment. Females tended to present with more impairments in spatial abilities, complex attention and working memory, whilst male prisoners had more widespread and generalised impairments in all areas, apart from basic processing speed and basic perceptual abilities. It is likely the females’ cognitive profile is the result of substance use, in particular, benzodiazepine use.
In contrast, the males’ impairment profile more resembles that seen in alcohol related brain injury and traumatic brain injury. This means that males and females with an ABI will present with different cognitive and behavioural profiles and may require different management strategies.