Watch what you say and how you say it: differential response to speech by participants with and without head injuries.

Previous research has shown that both prosodic and content variations in speech register are important when addressing all individuals. Motherese speech register has been associated with higher levels of perceived disability and is viewed more negatively by individuals with a history of head injury. This research was conducted to investigate the separate contributions of content and prosody in producing differential response to speech by individuals with and without a history of head injury. Participants included 210 introductory psychology students with and without head injuries. No significant demographic differences were found between these groups. Participants listened to 4 sets of audiotaped instructions from afictitious home economics teacher containing prosodic and content variations. Afterward, they rated the teacher on the following dimensions: liking, positive impact, negative impact, grade level being taught, and whether they would recommend hiring this teacher. Analysis of variance revealed there were no significant group differences between participants rating with normal speech. As expected, both groups favored the normal speech register over motherese. However, the group with head injuries consistently rated the speech with motherese content as more negative, less likable, less likely to hire, and aimed at a lower grade level. Participants with head injuries also rated the speech register with motherese prosody as less likable and less likely to hire. These results suggest that when addressing individuals with head injuries, both what you say and how you say it are important.

Prospective remembering in younger and older adults: role of the prospective cue.

In these studies, adult age differences in event-based prospective memory were examined using an adapted version of G.O. Einstein and M.A. McDaniel's (1990) task. In Experiments 1-3, we varied prospective cue specificity by assigning a specific target word or an unspecified word drawn from a given taxonomic category. In Experiment 3, we manipulated cue typicality by presenting low or high typicality target words. Results yielded positive effects of cue specificity on prospective performance. Age effects occurred when high typicality target words served as prospective cues (Exps. 1 and 3), but younger and older adults performed comparably with moderate and low typicality words (Exps. 2 and 3). Hierarchical regression analyses indicated that age accounted for a small but significant amount of variance in prospective memory, although the contribution of age was substantially reduced after statistically controlling for recognition memory. Implications of these data for current views on prospective remembering are discussed.

On the duration of spatial fluency measures.

Various measures of spatial fluency have been developed and have been shown to be sensitive to right frontal lobe dysfunction. Patients with diffuse cerebral injuries (traumatic brain injury) also show impaired performance. Administration times for these tests range from three to five minutes. It is well known that longer tests provide more reliable data. In the present study, the base rates of unique designs and perseverative errors on the Five-Point Test were examined minute-by-minute for ten minutes, in a sample of healthy young adults (n=80). Contrasts between each minute showed significant decreases in number of unique designs to the ninth minute (significant at p<.001). Contrasts between each minute revealed significant increases (significant at p<.00l) in percentage of perseverative errors to the eighth minute. Data demonstrating the progressive decrease of unique designs and progressive increase of perseverative errors as a function of time have important implications for clinical practice. Optimal administration time is considered in the context of clinicians' objectives.

Stability of postconcussion symptomatology differs between high and low responders and by gender but not by mild head injury status.

A large sample of undergraduates (N = 2,326) were screened for general health. The screen discretely included items assessing postconcussion symptomatology and neurologic history. A subsample of experiment-blind participants whose self-reported postconcussion symptom levels were >0.5 SD below the screening sample mean (low symptomatic; n = 45) or >0.5 SD above the screening sample mean (high symptomatic; n = 53) were re-evaluated for postconcussion symptomatology 3 to 90 days later. The sample included 50 participants who reported history of mild head injury (MHI) and 48 controls. MHI was defined as loss of consciousness of < or =20 minutes within the past 10 years, but no more recent than 3 months. Persons with history of >1 head injury or with other neurologic history were not included in the study. The stability of postconcussion symptoms differed by high symptomatic versus low symptomatic presentation (high symptomatic presentation was more variable) and by gender (females were more variable), but not by actual history of MHI. Sex differences in self-reported postconcussion symptomatology are consistent with gender-related differences in reporting of other physical and psychological symptoms. In addition to demonstrating differences in the stability of self-reported postconcussion symptomatology, the current study provides normative test-retest data for the Postconcussion Symptom Checklist for extreme responders by gender and MHI status.

Stress as a diagnostic challenge for postconcussive symptoms: sequelae of mild traumatic brain injury or physiological stress response.

There is considerable controversy regarding whether persistent postconcussive symptoms (PCS) are injury-specific, in a subgroup of individuals after mild traumatic brain injury (TBI). The following findings have contributed to this controversy: (1) The base rate of PCS in mild TBI is comparable to uninjured controls; and (2) The severity of PCS covary with daily stress levels (Gouvier, Cubic, Jones, Brantley, & Cutlip, 1992). We examined this relationship further by evaluating the effects of experimental conditions of stress or relaxation on individuals with TBI and uninjured control subjects, with low and high PCS endorsement. We evaluated psychophysiological parameters, neuropsychological performance, and changes in PCS and stress perception. In our study, subjects with TBI increased PCS after engaging in cognitively challenging tasks, and demonstrated significant autonomic changes in the stress condition. Symptomatic TBI subjects exposed to high stress had increases in PCS complaints, decreased speed of information processing, and subtle memory deficits. Our results suggest that PCS are injury-specific and that individuals with a history of TBI are susceptible to the effects of stress. Relaxation training including breathing retraining may be an effective means of decreasing PCS and cognitive complaints in subjects with mild TBI.

Are you sure you're really telling the truth?

The core constructs of psychological assessment, reliability and validity, are shown to be incomplete and lacking whenever base rates for the conditions under evaluation skew markedly from 50/50. Under such circumstances, base rate information can exert a greater influence on diagnostic accuracy that is typically recognized among practitioners. The influence of base rates is so profound, that conclusions based on reliable and valid test data are often, more probably than not, wrong! This paper outlines our historical understanding of the "base rate fallacy", and offers explanations for its persistence in the practice of diagnostic psychology. Recommendations for self-monitoring and policing of our profession are offered, in order that neuropsychology might improve its diagnostic accuracy at a rate more comparable to the progress made in similar fields in medicine.

Quantitative PET scan findings in carbon monoxide poisoning: deficits seen in a matched pair.

Quantitative positron emission tomography (PET) was utilized to establish the degree and localization of central nervous system dysfunction in 2 adult patients 3 years status postchronic carbon monoxide poisoning. The individual PET scans were compared against a composite scan made up of 32 normals using a z transformation statistical parametric map. Neuropsychological findings indicated marked anterior frontal lobe syndrome in the context of far-above-average intelligence, memory, and language. They also showed manifest frontal symptoms in activities of daily living that resulted in vocational disability in each case. PET analysis revealed substantially decreased metabolism in the orbitofrontal and dorsolateral prefrontal cortex as well as in areas of the temporal lobe for each individual. Individual scans were very similar and consistent with patient's presenting symptoms, and changed life circumstances. This report represents the first quantitative functional neuroimaging study relevant to carbon monoxide poisoning.

External validation of the equivalence of two computational formulas for a WAIS-R seven-subtest short form.

The usefulness of an abbreviated form of the Wechsler Adult Intelligence Scale-R (WAIS-R) has been noted by several researchers. A 7-subtest short form yielding estimates of Verbal, Performance, and Full Scale IQs (FSIQs) has shown good reliability and validity. Both weighted and prorated formulas have been used interchangeably to compute estimated IQs derived from this short form. The purpose of this study was to compare the equivalence of these formulas with the full WAIS-R in a mixed clinical sample. Results show that both formulas produce nearly identical results, with neither formula emerging as clearly superior over the other; validity coefficients for WAIS-R IQs ranged from .95 to .97. A very slight absolute advantage was noted for the prorated over the weighted formula in that it resulted in fewer IQ differences greater than 2 standard errors of measurement, fewer misclassifications of FSIQ, and stronger correlations with WAIS-R Verbal, Performance, and FSIQs.

Cross-validation of the two- and three-subtest short forms of the Wechsler Memory Scale-Revised.

Researchers have noted the usefulness of an abbreviated form of the Wechsler Memory Scale-Revised. A number of studies have suggested that estimating General Memory and Delayed Recall scores using 3-subtest or 2-subtest equations decreases testing time without sacrificing reliability or clinical accuracy. The purpose of this study was to cross-validate previous results in a mixed clinical sample, as well as to examine the validity of the 2-subtest equations. Results of this study provide support for the use of the 3-subtest short form to estimate memory ability in normal and cognitively impaired patients. However, using only 2 subtests to estimate index scores resulted in a decline in predictive accuracy.

Reconstructive memory bias in recall of neuropsychological symptomatology.

Subjective recall of symptoms among nonlitigants with closed-head and back injuries and non-injured participants with high and low levels of life stressors was evaluated. All participants completed a demographic questionnaire, the Brief Symptom Inventory, and a symptom checklist. Recall of symptoms by participants with closed-head and back injuries was consistent with perceptions of being worse now than they were before their injuries. The results further suggest that these participants tend to overestimate the actual degree of change that has taken place by recalling fewer pre-injury symptoms than control participants. In addition, participants with closed-head injuries, but not with back injuries, showed significantly higher levels of symptom endorsement now than controls.

Malingering detection in a mentally retarded forensic population.

Thirty-nine patients in a forensic mental hospital were evaluated using the Structured Interview of Reported Symptoms (SIRS) and several tests used for detecting malingered psychiatric and neuropsychological dysfunction. Patients were initially classified by a multidisciplinary team as nonmalingering participants (n = 12) and known malingerers (n = 9). All participants in both groups were pretrial and had been found incompetent to stand trial by the court. Eighteen more patients found to be not guilty by reason of insanity by the courts were included in the study. Using the SIRS alone, 95% overall classification accuracy was obtained. When the scores on the Dot Counting Test, Memory for Fifteen Items Test, and the M-Test were added to the discriminant function, all patients were correctly classified to the respective groups. The results are discussed in terms of complimenting interdisciplinary team diagnosis with psychological tests for malingering.

Malingering detection with the dot counting test.

The Dot Counting Test (DCT) offers a technique for malingering detection that is less transparent than the forced-choice testing that has received so much recent attention. The present study defined six dependent variables derived from DCT responses, and examined these variables in the context of differentiating simulators from non-simulators. Four groups of subjects were studied: normal controls, neuropsychological evaluation patients, naive (uncoached) malingering simulators, and sophisticated (coached) malingering simulators. Results demonstrate that the DCT provides several different scores that significantly differ between simulators and non-simulators. The DCT appears to hold promise as an additional tool to neuropsychologists in the detection of malingering.

Differential vulnerability between postconcussion self-report and objective malingering tests in identifying simulated mild head injury.

The present study examined the ability of analog malingerers to feign postconcussion symptoms and neuropsychological performance patterns seen in mild head-injured patients. Experimental subjects were randomly assigned to either a control condition, asked to feign deficits consistent with mild head injury without task specific instruction, or feign deficits while given task-specific instruction. A separate group of mild head-injured patients served as a clinical comparison group. Analog malingering groups accurately simulated levels of postconcussive symptoms seen in the mild head-injured patients. However, poorer performance was displayed by the analog malingerers on the objective malingering tests. Coaching did not facilitate realistic patterns of performance for analog malingerers. The results of this study indicate that analog malingerers accurately replicated self-reported postconcussive symptoms, but were less able to simulate objective clinical malingering test performance. These results suggest that self-report measures of postconcussive symptoms and clinical tests are differentially vulnerable to simulation attempts.

Head injury in a college population: analysis of epidemiological factors.

Head injuries are frequent occurrences, and the majority are considered mild Most epidemiological studies have used hospitalized cases, and, as a result, those who sustain a head injury but do not receive intensive medical attention are not considered It can be assumed that those not receiving medical attention most likely sustained mild head injuries A few researchers have examined self-reported head injury, but the data is still limited Little is known about those individuals who incur head trauma and resume normal functioning without treatment The purpose of this study was to identify and describe the epidemiological correlates of head injury within a young high functioning population The present study examined head injury and its associated factors in a college sample, which included such areas as demographics, nature of head injury, and prevalence of postconcussion symptoms.

Influence of prior knowledge and experience on the ability to feign mild head injury symptoms in head injured and non-head-injured college students.

The present study investigated the effects of personal knowledge, experience and beliefs about traumatic brain injury (TBI) on persons' ability to successfully feign neuropsychological impairment. Head-injured and non-injured subjects completed the Head Injury Misconception Survey, and were evenly divided into malingering or control (do best) conditions. Subjects were given a scenario which asked them to imagine that they had been in a prior accident and were involved in litigation. They were then asked to either malinger or respond in the best way possible to a battery of neuropsychological tests. While instructions to malinger had a pronounced effect, knowledge of brain injury did not significantly influence an individual's ability to feign neuropsychological impairment. Future directions in the study of malingering are also discussed.

Effects of sophistication and motivation on the detection of malingered memory performance using a computerized forced-choice task.

The present study employed a computerized forced-choice recognition memory task, the Multi-Digit Memory Test (MDMT), to examine the effects of instructional set (i.e., dissimulation information provided subjects) and motivation (i.e., monetary incentive) on simulated malingering behavior in a group of 119 university undergraduate students and 33 patients sustaining varying severity of closed-head injury. For the nonpatient groups, a significant effect of instructional set was revealed. Motivational incentive, however, did not affect forced-choice performance. Overall, significant performance differences emerged between all groups with nonmalingering students performing nearly perfectly, the brain-injured patients performing well above chance levels, sophisticated student malingers performing at chance, and naive student malingers performing well below chance levels. These results suggest the MDMT may offer a clinically useful and convenient addition to a neuropsychological assessment when there is suspicion of feigned memory problems. These data also support the use of naive and sophisticated malingering subjects in further analog studies addressing this topic.

Rey Auditory-Verbal Learning Test: the effects of age and gender, and norms for delayed recall and story recognition trials.

Immediate recall and three measures of delayed memory performance were evaluated in 134 healthy adults aged 16-76. Gender of subjects had no Influence on performance for any of the acquisition or retention trials. Age influenced acquisition as memory load began to exceed five to six words, with older subjects exhibiting decreased capacity. There was little loss of information between the immediate and delayed recall trials for any age group. Norms for a 30-min delayed recall trial, commission errors on delayed recall, and delayed recognition using Rey's story recognition procedure are presented, and implications for clinical use are discussed.

Postconcussion symptoms and daily stress in normal and head-injured college populations.

The postconcussion syndrome is a term invoked to describe a constellation of cognitive (decreased memory and concentration), emotional (increased irritability and nervousness or anxiety), and physical (increased headaches and dizziness) changes that are commonly reported following minor or severe head injuries. The first section presents the development and validation of the Postconcussion Syndrome Checklist. The second section describes the daily changes in symptom reports as a function of daily stress levels. A population of head-injured subjects and controls monitored postconcussion symptoms and stress across a 6-week period. The frequency, intensity, and duration of symptoms reported were correlated with daily stress levels as measured by the Daily Stress Inventory for both groups. Yet, the number of symptoms reported by our head-injured group did not vary significantly from the normal subjects. The data support models which predict that postconcussion syndrome varies with stress, but the evidence for a reduction in the cerebral reserve capacity after head injury was not supported with this population. Explanations for this finding are presented and implications of this research and directions for future research are outlined.

Behavioral assessment and treatment of acquired visuoperceptual disorders.

Visuoperceptual deficits are common sequelae of damage to either hemisphere of the brain, but are typically more pronounced following injuries involving the right cerebral hemisphere. Common visuoperceptual disorders include visual field cuts, hemi-inattention and hemi-spatial neglect, hemi-perceptual deficits, and gaze and visual pursuit disturbances. A number of behavioral interventions have been developed to teach patients to compensate for acquired visual deficits. Studies addressing assessment and treatment issues in this area are reviewed, and future directions for research are outlined.