WAIS practice effects in clinical neuropsychology

Understanding beginning teachers' professional identity changes through job demands-resources theory

Teachers' professional identity is malleable. However, changes in first-year teachers' professional identity are under-documented in the literature. This study attempted to understand these changes using the job demands-resources (JD-R) model in the context of a two-wave investigation before and after the first year of teaching (Time 1 and Time 2). A total of 464 elementary and secondary schoolteachers reported twice their perceived professional identity in terms of job satisfaction, occupational commitment, teacher self-efficacy, and motivation to teach. School characteristics were captured in terms of job demands and job resources at T2. Findings estimated by the rank-order change, the mean-level change, and the Reliable Change Index indicated significant declines in these teachers' professional identity over one year. Autoregressive change analysis revealed that growth opportunities (job resources) and emotional demands (job demands) in the school context played a major role in the observed declines. Suggestions and implications are discussed for key stakeholders of teacher education programs and teachers' professional development.

Long-term Sustained Cognitive Benefits of Vagus Nerve Stimulation in Refractory Depression

BACKGROUND

Treatment-resistant depression (TRD) is a serious chronic condition disabling patients functionally and cognitively. Chronic vagus nerve stimulation (VNS) is recognized for the management of TRD, but few studies have examined its long-term effects on cognitive dysfunction in unipolar and bipolar resistant depression.

OBJECTIVE

The purpose of this study was to assess the course of cognitive functions and clinical symptoms in a cohort of patients treated with VNS for TRD.

METHODS

In 14 TRD patients with VNS, standardized clinical and neuropsychological measures covering memory, attention/executive functions, and psychomotor speed were analyzed prestimulation and up to 2 years poststimulation.

RESULTS

Vagus nerve stimulation patients significantly improved on cognitive and clinical measures. Learning and memory improved rapidly after 1 month of stimulation, and other cognitive functions improved gradually over time. Cognitive improvements were sustained up to 2 years of treatment. At 1 month, improvement in Montgomery-Åsberg Depression Rating Scale scores was not correlated with changes in any of the cognitive scores, whereas at 12 months, the change in Montgomery-Åsberg Depression Rating Scale score was significantly correlated with several measures (Stroop interference, verbal fluency, and Rey-Osterrieth Complex Figure delayed recall).

CONCLUSIONS

In recent years, a growing interest in cognitive dysfunction in depression has emerged. Our results suggest that chronic VNS produces sustained clinical and cognitive improvements in TRD patients, with some mental functions improving as soon as 1 month after the initiation of the VNS therapy. Vagus nerve stimulation seems a very promising adjunctive therapy for TRD patients with cognitive impairment.

Estimating Full Scale IQ While Minimizing the Effects of Practice

The present study attempted to ascertain the best estimate of true Wechsler Adult Intelligence Scale-Revised (WAIS-R) Full Scale IQ (FSIQ) when confronted with an individual who recently had been administered the WAIS-R. Sixty-five college undergraduate participants were administered the WAIS-R twice within 14 days. WAIS-R summary scores, factor scores, and short-form estimates obtained from the second assessment were compared to FSIQ at the first evaluation. The results indicated that Verbal IQ, the Verbal Comprehension factor score, and subtracting 6 points from the current FSIQ are the least affected by repeat assessment and the most accurate estimates of FSIQ at the first evaluation. Use of these estimates of FSIQ are encouraged when evaluating an individual who has been administered the WAIS-R in the recent past.

Practice effects distort translational validity estimates for a Neurocognitive Battery

INTRODUCTION

With the globalization of biomedical research and the advent of "precision medicine," there is increased need for translation of neuropsychological tests, such as computerized batteries that can be incorporated in large-scale genomic studies. Estimates of translational validity are obtained by administering the test in the original and the translated versions to bilingual individuals. We investigated the translation of a neuropsychological battery from English to Arabic and how practice effects influence translational validity estimates.

METHODS

The Penn computerized neurocognitive battery (Penn CNB) includes tests that were validated with functional neuroimaging and provides measures of accuracy and speed of performance in several cognitive domains. To develop an Arabic version of the CNB, the English version was translated into Arabic, then back translated and revised. The Arabic and the original English versions were administered in a randomized crossover design to bilingual participants (N = 22).

RESULTS

Performance varied by cognitive domain, but generally improved at the second session regardless of the language of the initial test. When performance on the English and Arabic version was compared, significant positive correlations were detected for accuracy in 8/13 cognitive domains and for speed in 4/13 domains (r = .02 to .97). When the practice estimates using linear models were incorporated, the translational validity estimates improved substantially (accuracy, r = .50-.96, speed, r = .63-.92, all correlations, p = .05 or better).

CONCLUSION

While crossover designs control for order effects on average performance, practice effects, regardless of language, still need to be removed to obtain estimates of translational validity. When practice effect is controlled for, the Arabic and English versions of the Penn-CNB are well correlated, and the Arabic version is suitable for use in research.

Repeated neuropsychological assessment in well-controlled epilepsy

BACKGROUND

The majority of patients with epilepsy are seizure-free, and repeated neuropsychological assessment may be highly relevant in this group. However, previous studies have not addressed the possible influence of important clinical variables on repeated neuropsychological assessment in this population.

METHODS

Using data from a large antiepileptic drug (AED) withdrawal study, we calculated the neuropsychological practice effects for 139 seizure-free patients with epilepsy and analysed the influence of different epilepsy-related factors on improvement that were observable 7 months after the initial neuropsychological assessment.

RESULTS

A clear and significant improvement in neuropsychological test performance was found for all the tests employed, regardless of AED withdrawal. Furthermore, patients characterized by evidence of brain pathology, such as known cerebral aetiology, pathological MRI and pathological EEG, showed less practice effects than patients not characterized by these variables. The differences were primarily evident for measures of verbal learning and memory.

CONCLUSION

The data obtained from this study suggest that the development of general norms for change in the particular patient population, as well as specific norms for change related to important clinical variables, might be necessary to be able to determine whether genuine neuropsychological changes have occurred in individual patients in this group.

Effects of practice on the Wechsler Adult Intelligence Scale-IV across 3- and 6-month intervals

A total of 54 participants (age M = 20.9; education M = 14.9; initial Full Scale IQ M = 111.6) were administered the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) at baseline and again either 3 or 6 months later. Scores on the Full Scale IQ, Verbal Comprehension, Working Memory, Perceptual Reasoning, Processing Speed, and General Ability Indices improved approximately 7, 5, 4, 5, 9, and 6 points, respectively, and increases were similar regardless of whether the re-examination occurred over 3- or 6-month intervals. Reliable change indices (RCI) were computed using the simple difference and bivariate regression methods, providing estimated base rates of change across time. The regression method provided more accurate estimates of reliable change than did the simple difference between baseline and follow-up scores. These findings suggest that prior exposure to the WAIS-IV results in significant score increments. These gains reflect practice effects instead of genuine intellectual changes, which may lead to errors in clinical judgment.

Do practice effects on Wechsler's Performance subtests relate to children's general ability, memory, learning ability, or attention?

The nature of practice effects on the Wechsler Intelligence Scale-Third Edition (WISC-III) Performance Scale was examined for 51 middle-class White children ages 11 to 13 years. The participants were tested twice on the six WISC-III Performance subtests (mean interval = 13 days) to determine whether the gain scores were significantly related to the children's ability level, memory, learning ability, and attention and motivation. Measures of these constructs were administered during the initial evaluation. Results indicated that retest gains on the separate subtests were uncorrelated with each other. Multiple regression analyses yielded some significant and meaningful results (e.g., a measure of long-term memory was a significant predictor of gains on Object Assembly), but, in general, few meaningful relations were yielded in these analyses.

Practice Effects Associated with the Repeated Assessment of Cognitive Function Using the CogState Battery at 10-minute, One Week and One Month Test-retest Intervals

There are many situations in which cognitive tests need to be administered on more than two occasions and at very brief test-retest intervals to detect change in group performance. However, previous literature has not specifically addressed these important issues. The main aim of the current study was to examine these two factors by using a computerized cognitive battery designed specifically for the repeated assessment of cognition (i.e., CogState) in healthy young adult individuals. A further aim of the study was to examine how many times the battery needed to be completed before performance, as measured by the battery, stabilized. Forty-five adults (age range: 18-40 years) completed the battery four times at 10-minute test-retest intervals, and a fifth time at an interval of one week. The results illustrated that when brief test-retest intervals were used (i.e., 10 minutes), performance stabilized after the second assessment, as significant practice effects were generally observed between the first and the second assessments. Practice effects were also observed on some of the tasks at a one-week test-retest interval. Due to these findings, 55 adults (age range: 18-40 years) completed the battery twice at 10-minute test-retest intervals (i.e., to eliminate the initial practice effect), and a third time at an interval of one month. No practice effects were observed. The implications of the results are discussed in terms of methods that can be adopted in order to minimize practice effects when this particular cognitive battery is used.

Premorbid IQ as a predictor for the course of IQ in first onset patients with schizophrenia: a 10-year follow-up study

The aim of the present study was to examine the longitudinal course of IQ and its heterogeneity in patients with schizophrenia, from the perspective of the two main "subtypes" of schizophrenia described in the literature: progressive cognitive deficit versus cognitive stabilisation or recovery. Premorbid IQ scores and WAIS IQ scores of 100 first onset patients were obtained at first hospitalization (T1) and after 10 years (T2). Significant changes in IQ over time were found, representing (i) at T1, a deterioration compared to premorbid intelligence (B=-6.3, 95% CI -9.5 to -3.0, p<0.0001), followed by (ii) a recovery at T2 where IQ matched premorbid intelligence again (B=0.5, 95% CI -3.1 to 4.0, p=0.79). In addition, a significant interaction was found between course of IQ over time and estimated premorbid IQ, demonstrating that subjects with lower premorbid IQ levels remained stable over time whereas in individuals with higher premorbid IQ levels a pattern of deterioration was evident at T1, followed by a recovery up to premorbid level at T2. The data confirm the importance of estimated premorbid IQ as an indicator of the longitudinal course of cognitive functioning in patients with schizophrenia and add evidence to the hypothesis of heterogeneity or "subtypes" of schizophrenia. The data, however, do not confirm the existence of progressive deterioration of cognitive functioning. Rather, catching up of cognitive function later in the course of the illness may take place in those whose deficits become apparent in the early phases of illness, whereas those with the most severe premorbid impairments remain stable.

Traumatic brain damage in minor head injury: relation of serum S-100 protein measurements to magnetic resonance imaging and neurobehavioral outcome

OBJECTIVE

The present study was conducted to validate S-100 protein as a marker of brain damage after minor head injury.

METHODS

We studied 50 patients with minor head injuries and Glasgow Coma Scale scores of 13 to 15 in whom computed tomographic scans of the brain revealed no abnormalities. Serum levels of S-100 protein were measured at admittance and hourly thereafter until 12 hours after injury. Magnetic resonance imaging and baseline neuropsychological examinations were performed within 48 hours, and neuropsychological follow-up was conducted at 3 months postinjury.

RESULTS

Fourteen patients (28%) had detectable serum levels of S-100 protein (mean peak value, 0.4 microg/L [standard deviation, +/- 0.3]). The S-100 protein levels were highest immediately after the trauma, and they declined each hour thereafter. At 6 hours postinjury, the serum level was below the detection limit (0.2 microg/L) in five (36%) of the patients with initially detectable levels. Magnetic resonance imaging revealed brain contusions in five patients, four of whom demonstrated detectable levels of S-100 protein in serum. The proportion of patients with detectable serum levels was significantly higher when magnetic resonance imaging revealed a brain contusion. In patients with detectable serum levels, we observed a trend toward impaired neuropsychological functioning on measures of attention, memory, and information processing speed.

CONCLUSION

Determination of S-100 protein levels in serum provides a valid measure of the presence and severity of traumatic brain damage if performed within the first hours after minor head injury.

Relationship of IQ to verbal learning and memory: test and retest

The relationship between Wechsler Adult Intelligence Scale-Revised (WAIS-R) IQ and performance on measures of memory was examined in 64 adults tested twice at a 2-week interval. Repeated measures analyses of variance revealed that individuals with Low-Average WAIS-R Full Scale IQ scores performed significantly more poorly than did individuals with Average and High-Average Full Scale IQs on memory measures including the Wechsler Memory Scale-Revised (WMS-R) General Memory and Delayed Recall indices, as well as California Verbal Learning Test (CVLT) Total Words. Learning Slope, and Discriminability. Although all three groups demonstrated significant practice effects on each memory measure, group differences in performance persisted at retest. Multiple regression analyses revealed that WAIS-R factor scores Verbal Comprehension and Freedom from Distractibility accounted for up to 42% of the variance in WMS-R and CVLT indices. Moreover, WAIS-R performance at initial testing accounted for 22-41% of the variance in memory performance at retest. These results are discussed in the context of the construct stabilities of intelligence and memory, as well as the psychometric precision of the tests used to measure these constructs.

Assessment of cognitive deterioration in individual patients following cardiac surgery: correcting for measurement error and practice effects

Assessment of cognitive change in individual patients may be confounded by unreliability of test scores and effects of repeated testing. An index correcting for both problems is proposed and compared with change indices that do not or do not adequately deal with measurement error and practice effects. These indices were used to examine cognitive deterioration in a sample of 63 patients undergoing cardiac surgery. It was demonstrated that for test measures with a low reliability, failure to correct for measurement error resulted in overestimation of deterioration rates. For test measures with a high reliability, but showing substantial practice effects, failure to correct for practice effects resulted in underestimation of deterioration rates. With the proposed index, cognitive deterioration shortly after cardiac surgery was most frequently observed for attention and psychomotor speed, less frequently for verbal fluency, and only occasionally for learning and memory.

Issues associated with repeated neuropsychological assessments

Distinguishing practice effects from other factors in repeated neuropsychological assessments are discussed in the context of research studies and clinical/forensic assessments. Potential methodological procedures for reducing the impact of practice effects in research settings are outlined. In contrast, the potential clinical utility and interpretation of practice effects in clinical assessments and forensic evaluations are highlighted.

Serial cognitive testing in temporal lobe epilepsy: longitudinal changes with medical and surgical therapies

Cognitive testing was repeated at intervals ranging from 1 to 8 years in 47 adult patients with temporal lobe epilepsy (TLE). Each patient underwent standardized batteries, including the Wechsler Adult Intelligence Scale, Revised (WAIS-R), and Wechsler Memory Scale (WMS). Both surgically treated and nonsurgical patients were examined. The nonsurgical group underwent serial testing for clinical indications, usually for complaints of memory dysfunction. Longitudinal testing could not verify any mean deterioration of intellect or memory in this group; variance over time was similar to test-retest norms in healthy controls. WAIS-R scores before and after resection in the surgical group were similar to our serial WAIS-R data in nonsurgical patients. When we divided surgical patients according to side of epileptogenesis, we noted the expected differences in verbal and visual memory. Right-sided surgery patients improved significantly in Full-Scale IQ (FSIQ) and tended to improve in logical memory on postoperative testing. Patients undergoing left resections had no retest improvement and tended to show decrease in several measures of verbal memory. Our findings should stimulate continued investigation into the natural history of lateralized memory and intellectual function in epilepsy, particularly to clarify long-term cognitive outcome in nonsurgical patients.

Effects of practice of serial tests of attention in healthy subjects

The effects of practice on the serial performance of auditory and visual attention tasks were investigated in 10 healthy volunteers tested at 2 to 4 weekly intervals over eight test sessions using a battery of psychometric tests. Subjects as a group showed an ability to significantly (p = .05) improve their performances over time on all tests except for the Simple Reaction Time and Symbol Digit Modalities Test, the latter demonstrating a trend towards improvement (p = .07). Improvement when it occurred was almost uniformly linear and on tests such as the Pegboard and Stroop, was still discernable at the eighth session. On tests such as Paced Visual Serial Addition Task, floor effects were noted after five sessions and no further improvement was possible. In general, younger subjects tended to make fewer errors, perform quicker and improve for longer periods than their older counterparts. The results indicate that on tests of attention, healthy subjects have the ability to significantly improve performance with practice and this may extend over as many as eight discrete test sessions. The implications for neuropsychological research are discussed.

Encephalopathy and neuropathy in end-stage liver disease before and after liver transplantation

The nervous system involvement of 8 patients with end-stage liver disease was evaluated by means of clinical neurological, neuropsychological, neurophysiological and neuroradiological investigation before and 6-12 months after a successful liver transplantation. Preoperatively, all subjects (7 women, 1 man; mean age 40 years, range 30-54 years) exhibited decreased muscle strength and 2 patients manifested clinical signs of polyneuropathy. In neuropsychological tests, slight visuoconstructive apraxia, and disturbances of verbal memory and cognitive function were observed. Magnetic resonance imaging (MRI) revealed cerebral lesions in two patients. After transplantation, muscle strength reverted to normal in all patients, polyneuropathy improved and in all but 2 patients recovery of neuropsychological functioning was observed. Clinical signs of encephalopathy had disappeared. All patients were emotionally better adjusted after transplantation. Four subjects showed new, albeit mild changes in neurophysiological and neuropsychological tests postoperatively. We conclude that the majority of neurological impairment disappeared after liver transplantation. We want to stress that evaluation of neurological sequelae of liver transplantation needs to be based on assessments both before and after liver transplantation.

Effect of repeated administration of a neuropsychological battery in the elderly

Our study explored the magnitude of practice effect in repeated administration of NP measures that tap different cognitive domains in normal elderly subjects (N = 122) between ages 57 and 85, who were evaluated over three annual testing probes. Results revealed that WAIS-R PIQ, serial recall of words, WMS visual memory, and memory for logical passages (immediate and delayed) are likely to improve on the retest due to practice effect in individuals below age 75, whereas test-retest changes in older people show a different pattern. Implications of age-specific changes on retest for differential diagnosis of dementia in clinical practice were considered.

Neuropsychological improvement versus practice effect following unilateral carotid endarterectomy in patients without stroke

Patients who were admitted to hospital for a recent transient ischemic attack were entered into one of three groups based on medical and surgical characteristics; those with an abnormal neurological examination or a focal abnormality on CT Scan were omitted from the study. The two surgical groups (12 patients each) underwent either a left or right endarterectomy for a symptomatic atheroma of the ipsilateral carotid artery. The control group consisted of 12 patients who either demonstrated minor or nonexistent carotid abnormalities or a TIA distribution that was contralateral to what would otherwise have been a surgically treatable lesion. Patients were tested before surgery and again 6-8 weeks later with the WAIS, WMS, and other neuropsychological measures. Significant improvement on some measures at follow-up was strictly equivalent across all groups and was attributed to practice effects.

Base rate data for the WAIS-R: test-retest stability and VIQ-PIQ differences

The data analyzed were the 14 WAIS-R scores from each of the individuals who comprised the WAIS-R standardization sample. Examined was the individual VIQ-PIQ difference from only the initial examination of each of the 1880 subjects, as well as the test-retest change in each of the 14 WAIS-R scores for each of the 119 subjects who were retested. The results revealed that, although the WAIS-R has excellent psychometric reliability as reflected in its standard error of measurement of a VIQ-PIQ difference and its impressively high test-retest Pearson r values, the actual magnitudes of the differences between the VIQ and PIQ assessed in a single examination, or the magnitudes of gain or loss in the 14 scores on retest, for some of these normal individuals were sufficiently high that such base-rate data should be routinely considered by clinical neuropsychologists and other practitioners.