Biomedical subjects

G L Iverson

Publications and source records attributed to G L Iverson.

At least 19 recordsLinked to original sources

PubMed2006

No cumulative effects for one or two previous concussions.

BACKGROUND: Sports medicine clinicians and the general public are interested in the possible cumulative effects of concussion. OBJECTIVE: To examine whether athletes with a history of one or two previous concussions differed in their preseason neuropsychological test performances or symptom reporting. METHOD: Participants were 867 male high school and university amateur athletes who completed preseason testing with ImPACT version 2.0. They were sorted into three groups on the basis of number of previous concussions. There were 664 athletes with no previous concussions, 149 with one previous concussion, and 54 with two previous concussions. Multivariate analysis of variance was conducted using the verbal memory, visual memory, reaction time, processing speed, and postconcussion symptom composite scores as dependent variables and group membership as the independent variable. RESULTS: There was no significant multivariate effect, nor were there any significant main effects for individual scores. There was no measurable effect of one or two previous concussions on athletes' preseason neuropsychological test performance or symptom reporting. CONCLUSION: If there is a cumulative effect of one or two previous concussions, it is very small and undetectable using this methodology.

Adolescent↗

PubMed2001

Base rates of WAIS-R VIQ-PIQ differences in 1593 psychiatric inpatients.

The purpose of this study was to provide the psychologist with base-rate tables for the Wechsler Adult Intelligence Scale-Revised (WAIS-R) Verbal IQ-Performance IQ difference scores in 1593 psychiatric inpatients. Subtables also were provided for each of three primary psychiatric diagnoses (schizophrenia spectrum disorders, bipolar disorders, and depression). The base rates of VIQ-PIQ splits in the full inpatient sample, and those for the subsamples based on primary psychiatric diagnosis, were very similar to those reported in the WAIS-R standardization sample. Consistent with past research on the standardization sample, the VIQ-PIQ split was correlated positively with Full Scale IQ (FSIQ), indicating that larger splits are more common at the higher IQ levels. Therefore, base-rate tables also were provided for the total inpatient sample split into five IQ groupings.

Adult↗

PubMed2001

Predicting complaints of impaired cognitive functioning in patients with chronic pain.

Patients with chronic pain often complain of difficulties with cognitive functioning. Previous studies suggest that these occur with no history of head trauma or neurological disease. This study examined potential predictors of cognitive complaints in 275 consecutive patients referred to a university pain management center. Patients completed a brief set of self-report measures of problems with cognitive functioning, biographical information, pain severity, pain location, depression, anxiety, sleep quality, medication use, and litigation status during their first visit to the clinic. The most frequently reported cognitive complaints included forgetfulness (23.4%), minor accidents (23.1%), difficulty finishing tasks (20.5%), and difficulty with attention (18.7%). Fifty-four percent of patients reported at least one problem with cognitive functioning. Correlation analyses showed that using antidepressants, pain severity, pain-related anxiety, and depression were moderately associated with total cognitive complaints. Regression analyses showed that depression accounted for the largest unique proportion of variance in cognitive complaints (DeltaR2 = 29%). Given the high frequency of complaints of impaired cognitive functioning, this realm of functioning deserves routine assessment. When these complaints are encountered, a careful evaluation considering a range of neurological, social, and emotional influences is in order.

Adult↗

PubMed2001

Validation of the computerized assessment of response bias in litigating patients with head injuries.

The detection of malingering in neuropsychological assessment requires valid measures of incomplete effort. The Computerized Assessment of Response Bias (CARB) is a digit-recognition procedure designed to detect poor effort during a neuropsychological evaluation. We examined the CARB performance of a consecutive series of litigating patients (N = 119) with a full range of head-injury severity, from trivial to severe. Patients with trivial or mild head injuries performed more poorly than did patients with frank brain injuries. Specifically, patients with moderate to severe traumatic brain injuries obtained higher total scores and demonstrated briefer response latencies than did patients with trivial or mild head injuries.

Adult↗

PubMed2001

Measuring adaptive behavior in inpatient neuropsychiatry: the Behavioural Assessment Scale.

The Behavioural Assessment Scale (BAS) was administered to a sample of 95 inpatients with neuropsychiatric conditions. The total scores in the sample ranged from 26 to 145 (maximum possible score is 163), without any evidence of the "floor effect" encountered with other tests used with this population. Investigation into the psychometric structure of the BAS revealed three factors interpreted as Daily Living Skills, Communication/Social Skills, and Problem Behavior. The high intercorrelation between the two dominant factors was interpreted as general sensitivity of the BAS to global decline in functioning associated with severity of illness. These results confirm a previous psychometric investigation carried out on an elderly psychiatric sample. A recommendation is made for interpreting subscales based on these factor domains when specific abilities are of interest and using a Global Functioning subscale as a measure of overall adaptive behavior for both adult and geriatric inpatient neuropsychiatry patients.

Activities of Daily Living↗

PubMed2001

Assessing depression in systemic lupus erythematosus: determining reliable change.

Systemic lupus erythematosus (SLE) can follow an unpredictable course. Clinicians and researchers use various self-report inventories to track aspects of the patient's functioning during the course of the illness (e.g. health status, pain, fatigue, quality of life and psychological status). These self-report inventories are used to measure improvement or deterioration as a function of the natural history of the disease process, or as a function of response to treatment. Proper interpretation of scores derived from these inventories requires an understanding of their psychometric properties, in particular, their reliability. It is important to calculate reliable change difference scores for tests commonly used in rheumatology so clinicians can determine if a change score is a reliable indicator of improvement or deterioration in individual patients (i.e. the change score is not likely to be due to measurement error). The purpose of this article is to illustrate the use of the reliable change difference scores when assessing depression in patients with SLE using the Beck Depression Inventory (BDI).

Depression↗

PubMed2001

Can malingering be identified with the judgment of line orientation test?

The purpose of this study was to evaluate recently proposed (Meyers, Galinsky, & Volbrecht, 1999) cutoff scores for biased responding on the Judgment of Line Orientation Test (JLO). A large sample of individuals involved in head injury litigation (N = 294) took the JLO and 2 tests designed to detect biased responding, the Computerized Assessment ofResponse Bias (CARB) and the Word Memory Test (WMT), as part ofa comprehensive neuropsychological evaluation. Patients were divided into groups on the basis of brain injury severity and whether or not they scored in the suspicious range on the CARB or WMT. The patients who were identified as providing biased responding on the CARB or WMT also scored significantly lower on the JLO. However, the Meyers et al. (1999) cutoff score correctly identified only 9.9% ofthis group, with a 1% possible false-positive rate. A different cutoff score was selected that had .22 sensitivity and .96 specificity. Overall, these results suggest that the JLO has limited utility as a screenfor biased responding; however, clinicians are encouraged to evaluate these scores carefully if they do not seem to make biological or psychometric sense.

Brain Injuries↗

PubMed2001

Measuring improvement or decline on the WAIS-R in inpatient psychiatry.

Psychologists in inpatient psychiatric settings sometimes are asked to assess whether patients improve or decline in intellectual functioning. The impetus for this referral question may be a perceived change in psychiatric status, an acute neuropathological event, e.g., a head injury, or a suspicion of an early dementing process. For this study, data from 100 inpatients who completed the WAIS-R on two separate admissions were used to calculate confidence bands for measurement error surrounding test-retest difference scores. The analysis indicated that, if the retest interval is three months or less, significant practice effects must be factored into the interpretation of difference scores. A table for the interpretation of difference scores at different testing intervals is provided

Adolescent↗

PubMed2001

Effects of injury severity and cognitive exaggeration on olfactory deficits in head injury compensation claims.

The purpose of this study was to examine the relationship between exaggeration and scores on a test of olfactory discrimination in patients being assessed in connection with a claim for financial benefits. Participants were 448 patients referred to a private practice in Edmonton, Alberta, Canada for psychological or neuropsychological assessment, related to evaluation of impairment and disability resulting from a work-related or non-work related accident. All patients were involved in some form of compensation claim at the time of their evaluation. All patients completed two tests designed to detect exaggerated cognitive deficits, the Computerized Assessment of Response Bias (CARB) and the Word Memory Test (WMT) as part of their evaluation. The diagnostic groups included 322 head injury cases, varying from very minor to very severe. Normative data for the smell test were derived from 126 patients with orthopedic injuries who passed both the CARB and the WMT. Patients with more severe traumatic brain injuries were 10-12 times more likely to have olfactory deficits than persons with trivial to mild head injuries. In a subgroup of patients who failed either the CARB or the WMT, there was no relationship between injury severity and total scores on the smell test. Therefore, the dose-response relationship between brain injury severity and olfactory deficits is severely attenuated when patients who are probably exaggerating their cognitive deficits are included in the analyses. Those patients with trivial to mild head injuries who demonstrated adequate effort on both the CARB and the WMT were no more likely to show olfactory deficits than the non-head-injured orthopedic control subjects. Therefore, anosmia following mild traumatic brain injury should not be concluded from self-reports or from tests of smell unless tests of effort have been passed. Effort should also be controlled in group studies of olfaction.

Adult↗

PubMed2001

Interpreting change on the WAIS-III/WMS-III in clinical samples.

Clinicians should note that there is considerable variability in the reliabilities of the index and subtest scores derived from the third editions of the Wechsler Adult Intelligence Scale (WAIS-III) and the Wechsler Memory Scale (WMS-III). The purpose of this article is to review these reliabilities and to illustrate how they can be used to interpret change in patients' performances from test to retest. The WAIS-III IQ and Index scores are consistently the most reliable scores, in terms of both internal consistency and test-retest reliability. The most internally consistent WAIS-III subtests are Vocabulary, Information, Digit Span, Matrix Reasoning, and Arithmetic. Information and Vocabulary have the highest test-retest reliability. On the WMS-III, the Auditory Immediate Index, Immediate Memory Index, Auditory Delayed Index, and General Memory Index are the most reliable, in terms of both internal consistency and test-retest reliability. The Logical Memory I and Verbal Paired Associates I subtests are the most reliable. Data from three clinical groups (i.e., Alzheimer's disease, chronic alcohol abuse, and schizophrenia) were extracted from the Technical Manual [Psychological Corporation (1997). WAIS-III/WMS-III Technical Manual. San Antonio: Harcourt Brace] for the purpose of calculating reliable change estimates. A table of confidence intervals for test-retest measurement error is provided to help the clinician determine if patients have reliably improved or deteriorated on follow-up testing.

Journal Article↗

PubMed2000

Evaluation of a WMS-R malingering index in a non-litigating clinical sample.

The purpose of this study was to examine the prevalence of a Wechsler Memory Scale-Revised "malingering index" in a large sample of non-litigating individuals from an inpatient substance abuse program. Past research has demonstrated that experimental-malingerers often obtain substantially lower scores on the Attention/Concentration Index than on the General Memory Index. In the present study, only a small percentage of patients showed large General Memory - Attention/Concentration difference scores. These results provide further support for the validity of this difference score as a marker for non-optimal effort.

Adult↗

PubMed2000

California Verbal Learning Test indicators of suboptimal performance in a sample of head-injury litigants.

Cutoff scores suggested by Millis, Putnam, Adams, and Ricker (1995) for detecting suboptimal performance on indices from the California Verbal Learning Test (CVLT) were evaluated using data from 193 compensation-seeking participants. All participants claimed to have suffered a blow to the head in an accident causing subsequent deterioration in cognitive function. The participants were divided into those with negligible or possible mild brain injuries and those with clear evidence of moderate to severe brain injuries. In addition to the CVLT, all participants were administered the Computerized Assessment of Response Bias (CARB), a two-alternative forced choice test of recognition memory that is used to detect feigned cognitive impairment. For all CVLT indices, the distributions of outcome (valid vs. suboptimal performance) was unrelated to age and brain injury severity, and only weakly associated with education. However, a significantly higher proportion of males than females obtained scores in the suboptimal performance range. The CVLT indices were not fully redundant with each other with respect to binary participant classifications; substantial disagreement between pairwise classifications was found among those participants who obtained at least one score in the suboptimal performance range. CVLT index classifications were also found to be non-redundant with classifications based on CARB scores. The CVLT may thus add useful data over and above that obtained from symptom validity testing. However, the data suggest that the use of the strategy where any one or more below-cutoff CVLT scores are considered a positive indicator of suboptimal performance may be associated with a higher than acceptable false-positive error rate.

Adolescent↗

PubMed2000

Prevalence of abnormal CT-scans following mild head injury.

PRIMARY OBJECTIVE: The purpose of this study was to examine the prevalence of day-of-injury intracranial abnormalities in a large sample of patients with mild head injuries who were admitted to a Trauma Service. METHODS AND PROCEDURES: There were 912 patients who obtained admission Glasgow Coma Scale (GCS) scores of 13-15. MAIN OUTCOMES AND RESULTS: The base rate of complicated mild head injuries (i.e. abnormal CT scans) in this sample was 15.8%. However, nearly 25% of the sample, most of whom had very mild injuries, did not receive CT-scans. Therefore, the actual prevalence is more likely in the range 16-21%. There was a tremendous overlap in injury characteristics between patients with complicated and uncomplicated mild head injuries. None the less, there were modest, yet statistically significant, relationships between the presence of intracranial abnormalities and lower GCS scores, greater frequency of positive loss of consciousness, greater frequency of skull fractures, and lower GOAT scores.

Adolescent↗

PubMed2000

Detecting exaggeration and malingering in neuropsychological assessment.

Magnification of symptoms or nonoptimal effort on neuropsychological tests, within the context of head injury litigation, can have several independent or related underlying causes. Therefore, detecting exaggeration does not automatically indicate that the individual is malingering. This article reviews the evaluative and differential diagnostic process and provides the clinician with suggestions regarding assessment methods. A forensic evaluation that does not include careful consideration of possible negative response bias should be considered incomplete.

Brain Injuries↗

PubMed2000

Monitoring aggression and problem behaviors in inpatient neuropsychiatric units.

The Problem Behavior Recording System (PBRS) is a computer-based monitoring system for tracking aggression and other problem behaviors among inpatients on neuropsychiatric units. The authors describe the system and compare it with other tracking systems. In 1997 a total of 405 aggressive incidents on an aggressive-ambulatory neuropsychiatry unit were recorded on the PBRS, whereas only 112 incidents, or 28 percent, were documented in hospital incident reports. In a further analysis, nursing notes in the charts of three patients were examined for a three-month period; 34 aggressive incidents were documented, compared with 41 PBRS entries for the same patients. The chart review took nearly three hours to complete, compared with less than five minutes for the PBRS analysis.

Aggression↗

PubMed2000

Internal consistency and concurrent validity of two short forms of the Visual Form Discrimination Test.

The purpose of this study was to evaluate the reliability and concurrent validity of 2 short forms of the Visual Form Discrimination Test, referred to as first half (FH) and front-back (FB). Participants were a mixed sample of 225 patients seen for neuropsychological evaluations. The mean difference score between both short forms and the full form was less than 1 point. The short-total correlations were .85 and .86 for the FH and FB forms, respectively. A binary clinical decision rule, used to classify patients as normal or impaired, resulted in a 93.3% correct and a 94.7% correct classification rate for the FH and FB forms, respectively. It is concluded that the short form of the test, used in conjunction with a clinical decision rule, results in a very minor loss of accuracy.

Adult↗

PubMed2000

The Behavioural Assessment Scale: norms for factor-based subscales.

The Behavioural Assessment Scale (BAS) was developed to assess adaptive functioning in older persons with severe cognitive impairment. Previous research has demonstrated that BAS items can be rescored as 3 factor-based subscales entitled Daily Living Skills, Communication and Social Skills, and Problem Behavior, or as a global functioning aggregate. Normative information on these subscales is most helpful when based on a severely impaired sample because very little variation is present in an unimpaired population. In accordance with this goal, regression-predicted age- and mental-status-corrected percentile ranks are presented for these 4 subscales, and for the total score of the BAS.

Activities of Daily Living↗

PubMed2000

Clinical normative data for the WCST-64 following uncomplicated mild head injury.

Clinical norms for the 64-item Wisconsin Card Sorting Test (WCST-64) are presented. The norms were derived from 303 persons presenting for emergency services who met criteria for uncomplicated mild head injury. Most data were obtained within 2 days of injury, and the remaining data were obtained within 10 days of injury. The norms may be used to help determine whether or not a person's scores on the WCST-64 are typical of those seen shortly after sustaining an uncomplicated mild head injury.

Adult↗