Brain-damaged Subjects Research Articles

A Preliminary Evaluation of Emotional Experience and Expression Following Unilateral Brain Damage

In this preliminary study, hemispheric specialization for the experience and expression of emotion was investigated. Subjects were right-brain-damaged (RBD), left-brain-damaged (LBD), and normal control (NC) right-handed adults, carefully matched on demographic and neurological variables. Facial expressions were videotaped while subjects described recollected emotional and nonemotional experiences. Expressions were later rated by trained judges for emotional intensity and category accuracy. To examine experience, subjects evaluated the intensity and accuracy with which they had produced their monologues. RBDs produced less intense facial expressions and reported less intense emotional experiences than LBDs and NCs. LBDs rated themselves as producing expressions with less accuracy than did RBDs and NCs. These findings are consistent with research that supports the right-hemisphere hypothesis for emotion. In addition, judges' ratings and subjects' self-reports of emotional intensity were positively correlated for normal but not for brain-damaged subjects.

Explaining category-related effects in the retrieval of conceptual and lexical knowledge for concrete entities: operationalization and analysis of factors

Category-related effects in the retrieval of conceptual and lexical knowledge for concrete entities have been well documented in lesion studies, and also with functional imaging and electrophysiological approaches. For example, brain-damaged subjects may be impaired in the ability to recognize or to name animals but not tools, or the opposite pattern may obtain. One reason for these dissociations is that different patterns of defects tend to be caused by distinct lesion profiles, suggesting a relative tendency for certain neural systems to be involved in category-related knowledge. But we and others have also hypothesized that a variety of traits of concrete entities co-determine category-related dissociations. Such traits (‘factors’) include homomorphy (similarity of form), familiarity, value to perceiver, manipulability, characteristic motion, characteristic sensory modality of transaction (vision, touch, hearing), and typical age of acquisition. It is our view that the mix of factors relative to different conceptual categories plays a key role in the neuroanatomical distribution of records for those different categories, and is thus behind the systematic correlations between certain retrieval defects and damage to certain neural systems [12, 52]. In this study, we operationalized these factors and analyzed their intercorrelations. Stimuli were slides of 215 items from the conceptual categories of animals, fruits/vegetables, tools/utensils, vehicles, and musical instruments. The factors were operationalized on the basis of ratings obtained from 227 normal control subjects and on the basis of computer analyses of the digitized outlines of the stimuli. Principal components analysis revealed that 81% of the variability across items could be accounted for by three components: Component 1 ( practically useful, common items): high value to perceiver, tactile mode of transaction, high familiarity, low age of acquisition; Component 2 ( homomorphic, non-manipulable items): high homomorphy, low characteristic motion and manipulability; Component 3 ( items with characteristic sound): hearing mode of transaction, highly distinctive sounds. In another analysis, we found that the categories of animals versus tools/utensils differed significantly on the factors of homomorphy, familiarity, value, manipulability, characteristic motion, and touch. The factor structure we identified in this study may help explain category-related performance defects in brain-damaged subjects. The results lend support to our proposal that systematic differences in physical characteristics and contextual specification of concrete entities constitute a driving force behind the regionalization of neural systems related to the acquisition and retrieval of conceptual and lexical knowledge.

Performance characteristics of chronic schizophrenia on attention tests sensitive to unilateral brain damage.

The aims of this study were to investigate the lateralization hypothesis of schizophrenia, comparing chronic schizophrenics with unilateral brain-damaged subjects and normal controls, using attentional tests sensitive to the unilateral brain damage. Three attentional tests with different modes of stimuli, two vigilance tasks that require the self-paced or nonself-paced responses of subjects and one divided attention task, were administered to 28 chronic schizophrenics, 26 right and 24 left unilateral brain-damaged subjects, and 20 normal controls. The results indicated that schizophrenics performed a possible right-hemisphere damages pattern and also a left pattern in part, with failure of all tasks to show either pattern related to a number of differences between the three tasks. Furthermore, the attention deficits of schizophrenics are less than those of brain-damaged subjects but are clearly abnormal compared with the normal controls.

Age and education effects on brain-damaged subjects: ‘Negative’ findings revisited

In a recent publication Reitan and Wolfson (1995) report on the results of research in which they identify minimal effect for age and education on brain-damaged subjects. The purpose of the present article was to expand considerably on the cautionary comments expressed by these auth for their findings, with respect to (1) the problem of non-differentiated brain-damage samples both in terms of type and severity of neuropathology, and (2) psychometric issues, particularly in terms of the possibility of a Type II error (false negative results). An argument is presented which suggests that the relative absence of positive findings in the Reitan and Wolfson research is inconsistent with current theoretical and research indications of a high probability for compromised neuropsychological function in brain-damaged populations due to older age and lower education effects.

Nimodipine on Shuttle-box Avoidance Learning in Mice: No Impairment But Slight Improvement

The dihydropyridine calcium channel antagonist nimodipine was tested in mice of CD-1, C57BL/6, and DBA/2 strains subjected to shuttle-box avoidance training. In contrast with some findings of other authors showing impairment of shuttle-box avoidance learning by low doses of the drug in rats, nimodipine given IP before each training session at doses of 0.25, 0.5, 1, 2.5, or 5 mg/kg never impaired avoidance acquisition in mice. On the contrary, one dose of nimodipine (1 mg/kg) significantly improved avoidance acquisition in mice of the DBA/2 strain. The drug failed to impair avoidance performance in DBA/2 mice even if given acutely in the middle (third session) or at the end (fifth session) of the training period. The results contradict studies showing cognitive impairment induced by calcium channel blockers, and may provide some limited evidence in support of improved cognitive function in normal animals, although this effect is much less evident than in aged or brain-damaged subjects.

Patterns of performance by neuropsychiatric patients on the halstead category test: Evidence for conceptual learning in schizophrenic patients

We attempted to determine whether schizophrenic patients can improve their performance on an abstract reasoning task through experience, and to ascertain how the degree of learning compares with brain-damaged patients and patient controls. Two hundred and two schizophrenic patients, 179 brain-damaged patients and 229 patient controls were compared with regard to their improvement on Subtest 6 relative to Subtest 5 of the Halstead Category Test. Since Subtests 5 and 6 are based on the same concept, experience with Subtest 5 should reduce errors on Subtest 6. Subjects were also compared on Subtest 7, which evaluates learning and retention of the concepts associated with subtests 1 to 6. the schizophrenic subjects showed improvement on subtests 6 relative to 5 that was equal to the controls, with both groups showing significantly greater improvement than the brain-damaged subjects. The schizophrenic subjects also obtained a better mean score on Subtest 7 than did the brain-damaged subjects, but made significantly more errors than controls. We conclude that schizophrenic patients are capable of conceptual learning, and may not have fixed, irreversible impairment of abstraction ability.

Ability of the cognitive behavioral driver's inventory to distinguish malingerers from brain-damaged subjects

The Cognitive Behavioral Driver's Inventory (CBDI) was analyzed for its ability to discriminate brain-damaged patients from intact subjects who feigned brain-damage. In a sample of 251 neurologically impaired patients and 48 malingering volunteers, the computer-administered distinguished most malingerers from genuine patients. A jackknifed count revealed that the CBDI had 90% sensitivity for detecting malingerers, and 98% specificity for detecting non-malingering brain damaged patients. Success was due to the inability of malingerers to avoid quantitative errors: excessive response latencies, unusual error rates, inflated variability in response latencies, and excessive within-subject, between-item variability. The computer-administered battery may be an effective clinical tool for identifying patients who malinger brain-damage in neuropsychological testing.

Ability of the cognitive behavioral driver's inventory to distinguish malingerers from brain-damaged subjects

The Cognitive Behavioral Driver's Inventory (CBDI) was analyzed for its ability to discriminate brain-damaged patients from intact subjects who feigned brain-damage. In a sample of 251 neurologically impaired patients and 48 malingering volunteers, the computer-administered distinguished most malingerers from genuine patients. A jackknifed count revealed that the CBDI had 90% sensitivity for detecting malingerers, and 98% specificity for detecting non-malingering brain damaged patients. Success was due to the inability of malingerers to avoid quantitative errors: excessive response latencies, unusual error rates, inflated variability in response latencies, and excessive within-subject, between-item variability. The computer-administered battery may be an effective clinical tool for identifying patients who malinger brain-damage in neuropsychological testing.

Non-amnestic memory problems experienced by suspected brain damaged subjects

Non-amnestic memory problems experienced by suspected brain damaged subjects

Non-amnestic memory problems experienced by suspected brain damaged subjects : Sundet, K.

Non-amnestic memory problems experienced by suspected brain damaged subjects : Sundet, K.

Relationships of age and education to wechsler adult intelligence scale IQ values in Brain-Damaged and Non-Brain-Damaged Groups

Abstract Previous research (Reitan & Wolfson, 1995) has shown that age and education have a definite relationship among controls to scores on the General Neuropsychological Scale (GNDS), but minimal relationships among brain-damaged subjects. The present study investigated age and education relationships to WAIS VIQ, PIQ, and FSIQ values in brain-damaged and control groups, recognizing that these scores might differ from the GNDS in their sensitivity to brain damage as well as in their relationships to attribute variables. The findings yielded a complex set of results, with brain-damaged and non-brain-damaged groups being similar in some respects but different in others. In general, the results caution against the common practice of adjusting WAIS scores of brain-damaged subjects for age and education when the bases of the adjustments have been derived from non-brain-damaged controls.

Hemispheric specialization for discourse reports of emotional experiences: Relationships to demographic, neurological, and perceptual variables

This study examined hemispheric specialization for discourse reports of emotional and nonemotional experience in 16 right-brain-damaged (RBD), 16 left-brain-damaged (LBD), and 16 demographically-matched normal control (NC) right-handed adults. Patient groups did not differ on etiology, months post-CVA onset, and intrahemispheric lesion location. Subjects were requested to produce monologues about positive and negative emotional and nonemotional experiences. The lexical content of written transcriptions of these monologues was later rated for “emotionality” by naive judges. Overall, RBDs described experiences with less emotional intensity than did NCs and LBDs, providing support for right hemisphere involvement in lexical emotion. Although the RBDs in the current study demonstrated similar patterns of deficits in a prior study [9] on tasks involving lexical emotional perception, there were no significant relationships between the current measures of emotional expression and the previous measures of emotional perception. Finally, the expression and the perception data were examined with respect to intrahemispheric factors. Among the brain-damaged subjects, subcortical structures were more involved in reports of emotional experience, and cortical structures were more involved in the perception of emotion.

Using Prosody to Predict the End of Sentences in English and French: Normal and Brain-damaged Subjects

In an earlier study (Grosjean, 1983), it was found that listeners of English were surprisingly accurate at predicting the temporal end of a sentence when only given the part up to the “potentially last word”, that is a noun before an optional prepositional phrase of varying lengths. The present study investigated this phenomenon in four experiments. The first two experiments examined the prediction capabilities of listeners when presented with the whole sentence in segments of increasing duration and when presented with the potentially last word only. The results indicate that to be able to use prosody to predict the end of sentences correctly, subjects must have reached a point in thesentence where neither syntax nor semantics can contribute to the prediction process. The third experiment investigated whether the results obtained with English can be replicated in French, a language with a very different prosodic structure. It was found that unlike their English counterparts, French listeners were unablet...

Writing remediation using preserved oral spelling: A case for separate output buffers

Abstract The performance of a brain-damaged subject with severely impaired written spelling but markedly superior oral spelling ability is described. In common with a case reported by Lesser (1990), the patient showed an effect of spelling regularity for oral spelling (where she was worse at irregular words and made phonologically plausible errors) but showed effects of lexicality and word length for written spelling (where she was better at words than non-words and at short words than long words). The patient's initial writing performance and the significant improvements made in response to a remediation programme based on her superior oral spelling skills are reported. Models which suggest that both written and oral spelling share a common output buffer do not predict the occurrence of differing patterns of regularity, lexicality and word length for the two modes of spelling production. The paper will discuss the implementation and results of a theoretically motivated therapy programme, and the implicat...

Neuropsychological driving fitness tests for brain-damaged subjects

Objective: The study was carried out to evaluate and develop simple tools to assess the driving fitness of brain-damaged patients. Design: Four neuropsychological tests (predictors) were validated against an open-road driving test (criterion standard), which is used by the Department of Adaptations of the Dutch Driving Licensing Agency for assessing disabled drivers. Setting: The predictor tests were conducted in the involved scientific institute; the criterion standard involved participation in normal traffic. Patients: The subject group consisted of 33 men and 5 women who had recovered to a stabilized level from traumatic brain injuries. All had valid driving licenses when they were injured and they were considered to be potentially able to recommence driving. The subjects had a mean reported driving experience of 109.200km (SD = 86.300km). All subjects were recovered from a brain trauma with an average coma duration of 33 days (SD = 51 days). They were tested at least 1 year after the accident. All subjects had normal or corrected-to-normal vision and none used medications that, according to existing medical criteria, interfere with normal psychomotor or cognitive functioning. Ages at the time of the injury were between 17 and 55 years (mean, 29.8; SD, 10.9). Main Outcome Measures: Pearson product moment correlations (and explained variances) were calculated between the four predictor tests (a Perceptual Speed test, the WAIS Symbol-Digit Substitution subtest, a Tracking-Reaction dual task, and a Time Estimation task) and the open-road criterion standard. Results: The results indicated that performance on both the Perceptual Speed task and the Time Estimation task were significantly correlated with driving performance ( p < .05). When combined with coma duration and driving experience, the Perceptual Speed and Tracking-Reaction tests together explained 35.3% ( r = .59) of the variance in on-road driving performance. Conclusion: The amount of variance in open-road driving performance that could be accounted for by these tests was insufficient to completely replace an open-road driving fitness assessment. Also, based on other experimental documentation, it is concluded that more integral, domain-specific tests (eg, based on driving simulation) need to be developed.

Analysis of the Money Road-Map Test performance in normal and brain-damaged subjects

The Money Road-Map Test (MRMT) is a paper and pencil assessment of left-right discrimination. Some of the answers require an egocentric mental rotation in space. In a first experiment with 63 normal adults, we found that the accuracy and speed of the left-right decision process significantly decreased with a increasing degree of mental rotation required. A division of the MRMT turns in three categories with increasing mental rotation was proposed. In a second study (n = 50), patients with predominantly parietal brain lesions performed significantly worse than patients with predominantly frontal lesions. The significant group difference in total error score was especially due to the error scores of turns requiring mental rotation. The turn type analysis did not contribute to the lateralization of the lesions.

Selective interference with the maintenance of location information in working memory.

In 3 experiments, the nature of the events that interfere with spatial working memory was examined in order to clarify the roles of imagery, attention, and other processes in the short-term maintenance of location information. Looking and pointing at secondary task stimuli selectively interfered with memory for the locations of primary task stimuli. Secondary tasks that involved either mentally rotating primary task stimuli or making color or shape discriminations about primary or secondary task stimuli interfered with spatial working memory only if the required response was visually guided, but not if the response was verbal. Taken together, these findings support P.S. Goldman-Rakic's (1987) hypothesis regarding multiple representational domains and are consistent with known properties and connections of neurons believed to subserve the perception and maintenance of spatial information. A working memory task may be defined as one that requires holding onto information for a short time while it or other information is processed. Baddeley has proposed that there is a working memory system, specialized for concurrent storage and manipulation of information that is engaged by such tasks (for a recent overview, see Baddeley & Hitch, 1994). On the basis of studies of both intact and brain-damaged subjects (for a review, see Gathercole, 1994), Baddeley and his colleagues have divided the working memory system into three components: a phonological store for verbal information, a visuospatial sketchpad for visuospatial information, and a central executive that directs activities involved in manipulating and maintaining information in the two specialized stores. Perhaps the most studied example is the role of covert articulatory rehearsal in refreshing information in the phonological store. Performing a secondary task that requires articulation of verbal material decreases verbal memory span, a finding consistent with the hypothesized role of subvocalization in maintaining verbal information (e.g., Baddeley, Lewis, & Vallar, 1984). Much of the supporting evidence for the visuospatial component of Baddeley's model also comes from studies that use dual task procedures. These studies were designed to determine whether visuospatial and verbal working memory involve separate resources, and they have demonstrated that secondary verbal tasks interfere with memory for verbal information to a much greater extent than they interfere

Analysis of the Money Road-Map Test performance in normal and brain-damaged subjects

Analysis of the Money Road-Map Test performance in normal and brain-damaged subjects

Differential relationships of age and education to WAIS subtest scores among brain-damaged and control groups

The 11 subtests of the WAIS were compared to the attribute variables of age and education in a brain-damaged group and a non-brain-damaged (control) group. Because of the validity information available for the WAIS, the subtests for the WAIS rather than the WAIS-R were studied. Data analyses compared the level of age and education (each group subdivided at the median) on WAIS subtest scores and the correlations between attribute variables and subtest scores. The results revealed a number of differences between the two groups, with age and education having a weaker and less consistent relation to WAIS subtest scores in the brain-damaged group than in the control group. The findings suggest that the relationships between attribute variables and psychological test scores are complex, and that adjusting or transforming raw scores for brain-damaged subjects according to tables based upon non-brain-damaged subjects may produce erroneous data.

Relationships between specific and general tests of cerebral functioning

Abstract This study compared a group of control subjects with a group of brain-damaged subjects to determine whether “specific” neuropsychological measures were more sensitive to cerebral damage than “general” neuropsychological tests. The historical interest in localization and lateralization of cerebral functions has produced a strong emphasis on specific deficits, while general deficits, characterized by more complex functions, have received less directed attention. The results indicated that the general measures were significantly more sensitive to cerebral damage than were the specific measures. These findings identify the need for further investigation of the relationships between specific and general neuropsychological tests, since both types of tests are of value in comprehensive evaluations of individual subjects.