published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

The present study attempts to further define the neuropsychological characteristics associated with mild, moderate, and severe closed head injuries (CHI). The Dean-Woodcock Neuropsychological Assessment System (D-WNAS), a new neuropsychological battery, was administered to 119 CHI patients. The scores of the cognitive portion of the D-WNAS were then analyzed via cluster analysis in an attempt to further delineate neuropsychological impairment into more specific classifications occurring within types of brain trauma.Results suggested that the cognitive portion of the D-WNAS was effective in separating 4 subtypes within CHI, which are best interpreted as "profiles" or characteristics associated with "levels" of impairment. These levels of impairment were characterized by distinctly different subtest profiles, and were labeled as mild/high functioning, mild, moderate, and severe. The highest performing group, mild/high functioning, showed no neuropsychological deficits. The most severely impaired group was characterized by many deficits in short-term memory, visual stimuli, new learning, processing speed, visual-spatial abilities, abstract reasoning, attention/concentration, and remote memory tasks. A multivariate analysis showed that educational level was significant in differentiating between the subtypes and suggested that, depending on the severity of injury, educational level might also protect individuals from obtaining a poorer prognosis.From this investigation, the cognitive portion of the D-WNAS appears to offer valuable utility in identifying CHI patients and in further classifying their varied neuropsychological characteristics. Implications for diagnosing and differentiating between different levels or profiles of CHI was discussed. / Department of Educational Psychology

Computers are used for diagnostic and training in the neuropsychological rehabilitation. PLANTEST is a program for the IBM-PC that was developed for diagnostic support. It implements a test that gives information about the reduced ability of brain-injured patients to make plans regarding a certain task.The presented thesis describes a knowledge-based system that can be used to develop new test versions for PLANTEST. The program is called SolvePT and it can prove the solubility of test material used in PLANTEST. It can also automatically generate new test material. The program uses an exhaustive forward-chaining, depth-first search and is implemented in Prolog. The datastructures and algorithm of the program as well as space and time requirements are discussed. / Department of Computer Science

This thesis investigates the reading and writing of two patients with brain injuries due to cerebro-vascular accidents. Background tests show both patients to be moderately anomic and to have severe impairments in reading and writing nonwords. Investigations of the locus of impairment in AN's nonword reading showed her to have normal orthographic analysis capabilities but impairments in converting single and multiple graphemes into phonemes and in phonemic blending. The central issue studied was the role of lexical but non-semantic processes in reading aloud, writing to dictation and copying. For this purpose a "familiar nonword" paradigm was developed in which the patients learned to read or write a small set of nonwords either with or without any associated semantics. Both AN and AM were able to learn to read nonwords to which no meanings were attached but they could still not read novel nonwords. Both patients were unable to report any meanings for the familiar nonwords when they read them and there was no evidence that learning to read them improved their sub-lexical processing abilities. These results are evidence for a direct lexical route from print to sound that is dedicated to processing whole familiar words. It was also shown with AN that if nonwords are given meanings then learning is faster than if they are not given meanings. Experiments designed to test the hypothesis that nonwords are read by analogy to words found no support for it. Both patients have severe impairments in writing novel nonwords to dictation. As they can repeat spoken nonwords after they have failed to write them, this is not due to a short-term memory impairment. Despite their nonword writing impairments, both patients were able to write to dictation the meaningless nonwords that they had previously learned to read at the first attempt, and AN did so one month after learning to read them. Neither patient however, could write novel nonwords made by reordering the letters of the familiar nonwords. Furthermore, the familiar nonwords used spellings that are of a priori low probability. The familiar nonwords must therefore have been written using lexical knowledge. Tests of semantic association showed that the familiar nonwords evoked no semantic information that the patients could report. Function words dictated to AN evoked little semantic information but she wrote them to dictation significantly better than nonwords made by reordering their letters. These results are evidence for a direct lexical route for writing to dictation. Copying was studied both with and without a five second delay between presentation and response. AN was better at delayed copying of meaningless but familiar nonwords than she was at copying novel nonwords. She was also better at delayed copying of six-letter, bi-syllabic nonwords that she had been trained to copy than she was at copying novel nonwords made by recombining the first and second halves of the familiar nonwords such that these halves retained their positions from the parent nonwords. AN was better at copying function words than nonwords made by reordering their letters. She was also better at copying function words than she was at reading or writing them to dictation. These results are evidence for a direct lexical route for copying. AN and AM were both able to write to dictation nonwords that they had never heard or written before but with which they had been made visually familiar during a visual discrimination task. They must have used lexical knowledge to do so because the spellings used were of a priori very low probability. The creation of lexical orthographic information which can be retrieved from novel auditory input raises difficulties for current models and various possible interpretations are discussed. Finally, some of the possible implications of the re-learning abilities shown by these patients, for rehabilitation procedures are discussed briefly.

Neuropsychological rehabilitation following acquired brain injury is increasingly recognized as essential with the advancements in research evidence of its effectiveness, particularly as current estimates of disability following the most common forms of brain injury (traumatic brain injury and cerebrovascular accident) are so high. Improvements in predictive capabilities of researchers and clinicians are paramount in designing effective interventions. As many variables associated with outcome following brain injury are not controllable (e.g. severity of the injury, age, education), it is essential that rehabilitation programs design interventions to target those variables that are susceptible to amelioration. While personality factors have been shown to affect outcome in other medical illnesses, only a few studies have examined the influence of personality on outcome following neurorehabilitation for acquired brain injury. The results of these studies have been mixed. This study used the Millon Behavioral Medicine Diagnostic (MBMD) to predict outcome as measured by the Mayo-Portland Adaptability Index (MPAI-4) following brain injury rehabilitation in a heterogeneous sample of persons with acquired brain injuries (N = 50). It was hypothesized that specific coping styles scales from the MBMD (Introversive, Dejected, Oppositional), which are based on Millon's personality system, would predict outcome. Results indicated that both the Introversive and Oppositional coping styles scales accounted for significant amounts of variance in outcome beyond that accounted for by the severity of the injury alone (p < .001). In both cases, individuals with mild/moderate-moderate/severe limitations following completion of the rehabilitation program had significantly higher scores on the Introversive and Oppositional coping compared to individuals with more successful outcomes. The hypothesis that a dejected coping style would predict outcome was not supported. Implications for rehabilitation are discussed in the context of Millon's personality system.

This study utilized the Medical Symptom Validity Test (MSVT) and a set of standard neuropsychological instruments to determine the underlying construct of the MSVT that accounts for effort in mild traumatic brain injury (mTBI) patients by comparing/contrasting mTBI with dementia and an analog simulation. The results indicate that a common underlying neurocognitive construct (memory) exists between mTBI and dementia patients, which may account for poor effort as measured by the MSVT. Other underlying factors emerged for both groups, though they did not point to a common construct. This finding suggests that the overall effect of brain injury in neurologically impaired groups also impacts effort performance as measured by the MSVT. Similarly impaired performance patterns also emerged between mTBI and dementia groups in sub-groups that failed effort measures. Thus, failed effort tests may be a function of more pronounced deficits in these groups, rather than a function of effort. Finally, although similar effort profiles were noted between mTBI and analog simulators, the analog group was unable to mimic the neurocognitive effects of mTBI.

While the cognitive disturbances that frequently follow severe TBI are relatively well understood, the ways in which these affect the psychosocial functioning of people with TBI are yet to be determined and have thus received little attention in treatment research. Growing evidence indicates that that a significant proportion of individuals with TBI demonstrate deficits in the perception of affective information from the face, voice, bodily movement and posture. As accurate evaluation of emotion in others is critical for the successful negotiation of social interactions, effective treatments are necessary. Until recently, however, there have been no rehabilitation efforts in this area with TBI groups. The present research aims to redress this absence. The literature on emotion perception deficits in TBI is examined, and a theoretical rationale for intervention is presented. Several lines of research are reviewed which suggest that rehabilitation targeting such deficits is tenable. These include research on emotion perception remediation with other cognitively impaired populations, findings from cognitive neuroscience suggesting the potential for neuronal restoration after brain damage, and the successful applications of remediation techniques, in particular errorless learning and self-instruction, for treating other cognitive deficits in a range of neurological disorders and TBI. Discussion of this research is followed by a description of two randomised controlled trials aimed at improving emotion perception in individuals with TBI. The findings are discussed with reference to useful theoretical models of rehabilitation, learning and emotion perception. Suggestions for future directions of research are outlined together with relevant design issues.

published_or_final_version / Speech and Hearing Sciences / Doctoral / Doctor of Philosophy

While the cognitive disturbances that frequently follow severe TBI are relatively well understood, the ways in which these affect the psychosocial functioning of people with TBI are yet to be determined and have thus received little attention in treatment research. Growing evidence indicates that that a significant proportion of individuals with TBI demonstrate deficits in the perception of affective information from the face, voice, bodily movement and posture. As accurate evaluation of emotion in others is critical for the successful negotiation of social interactions, effective treatments are necessary. Until recently, however, there have been no rehabilitation efforts in this area with TBI groups. The present research aims to redress this absence. The literature on emotion perception deficits in TBI is examined, and a theoretical rationale for intervention is presented. Several lines of research are reviewed which suggest that rehabilitation targeting such deficits is tenable. These include research on emotion perception remediation with other cognitively impaired populations, findings from cognitive neuroscience suggesting the potential for neuronal restoration after brain damage, and the successful applications of remediation techniques, in particular errorless learning and self-instruction, for treating other cognitive deficits in a range of neurological disorders and TBI. Discussion of this research is followed by a description of two randomised controlled trials aimed at improving emotion perception in individuals with TBI. The findings are discussed with reference to useful theoretical models of rehabilitation, learning and emotion perception. Suggestions for future directions of research are outlined together with relevant design issues.

Pharmacological interventions to treat Human Immunodeficiency Virus (HIV) with antiretrovirals (ARVs), have dramatically improved the survival rates of HIV positive children maturing into adulthood. However, HIV-associated neurocognitive decline still persists in the era of ARVs. Within the framework of brain plasticity, a number of researchers have begun to assess the feasibility of cognitive rehabilitation therapy as a complement to ARVs to reverse neurocognitive decline as a result of HIV (e.g., Becker et al., 2012). Only one study has been conducted in South Africa, by Zondo & Mulder (2014), assessing the efficacy of cognitive rehabilitation in a paediatric sample. The current research builds on the above mentioned study by implementing an experimental approach to examine the effect of cognitive rehabilitation in a sample of both HIV positive and HIV negative children. Five HIV positive and six HIV negative children were assigned to either an experimental or control group. The experimental group underwent two months of cognitive rehabilitation therapy remediating sustained attention, whereas the control group took part in placebo activities. Sustained attention measures were taken before and after the intervention training sessions, using a sustained attention subtest from the Test of Everyday Attention for Children (TEA-CH). A Mann Whitney U Test revealed that the experimental group (Mdn=38.50) did not differ significantly from the control group (Mdn = 37.00) after the cognitive rehabilitation intervention, U=12.00, z= -.55, p= .66, r= -.17. But a Wilcoxon Signed Rank Test found that there was a significant improvement from pretest scores (Mdn=31.00) to posttest scores (Mdn=38.00) following the rehabilitation for HIV positive participants in the sample, T=15.00, z = -2.02, p= .04, r= -.90. This raises the possibility that cognitive rehabilitation could be used as a low cost intervention in underdeveloped contexts