Zita Bouman

Different types of working memory binding in epilepsy patients with unilateral anterior temporal lobectomy

The medial temporal lobe is an important structure for long-term memory formation, but its role in working memory is less clear. Recent studies have shown hippocampal involvement during working memory tasks requiring binding of information. It is yet unclear whether this is limited to tasks containing spatial features. The present study contrasted three binding conditions and one single-item condition in patients with unilateral anterior temporal lobectomy. A group of 43 patients with temporal lobectomy (23 left; 20 right) and 20 matched controls were examined with a working memory task assessing spatial relational binding (object-location), non-spatial relational binding (object-object), conjunctive binding (object-colour) and working memory for single items. We varied the delay period (3 or 6s), as there is evidence showing that delay length may modulate working memory performance. The results indicate that performance was worse for patients than for controls in both relational binding conditions, whereas patients were unimpaired in conjunctive binding. Single-item memory was found to be marginally impaired, due to a deficit on long-delay trials only. In conclusion, working memory binding deficits are found in patients with unilateral anterior temporal lobectomy. The role of the medial temporal lobe in working memory is not limited to tasks containing spatial features. Rather, it seems to be involved in relational binding, but not in conjunctive binding. The medial temporal lobe gets involved when working memory capacity does not suffice, for example when relations have to be maintained or when the delay period is long.

Clinical validation of the WMS-IV-NL brief cognitive status exam (BCSE) in older adults with MCI or dementia

ABSTRACT Background: The Brief Cognitive Status Exam (BCSE) is a new, optional subtest of the Wechsler Memory Scale-IV (WMS-IV) developed for rapid detection of cognitive deficits. We examined the clinical validation of the Dutch version of the BCSE in older adults with mild cognitive impairment (MCI) or dementia, comparing it to the Mini-Mental State Examination (MMSE). Method: BCSE and MMSE were administered in 39 older adults with MCI, 51 with dementia and 96 matched healthy controls. Results: Our results show that the BCSE is a valid screening instrument, with psychometric properties similar to the widely used MMSE. High correlations were found between the BCSE and MMSE (r = 0.79, n = 183, p < 0.001). Furthermore, a BCSE cut-off score ≤ 42 revealed a sensitivity of 96% a specificity of 92%, a positive predictive value of 86% and a negative predictive value of 97%, whereas the MMSE cut-off score of ≤ 24 showed values of 84%, 96%, 91%, and 92%, respectively. Sensitivity, specificity, positive and negative predictive values to detect MCI compared to controls was 81%, 80%, 61%, and 92%, respectively, on the BCSE, with a cut-off score of ≤ 46, and 84%, 76%, 57%, and 92%, respectively, on the MMSE, with a cut-off score of ≤ 27. Conclusions: The Dutch version of the BCSE is a clinically valid screening instrument for the detection of cognitive impairment in patients with dementia. Nevertheless, for distinguishing older adults with MCI from healthy controls both the BCSE and MMSE have limitations.

Clinical utility of the Wechsler Memory Scale - Fourth Edition (WMS-IV) in patients with intractable temporal lobe epilepsy

INTRODUCTION The Wechsler Memory Scale (WMS) is one of the most widely used test batteries to assess memory functions in patients with brain dysfunctions of different etiologies. This study examined the clinical validation of the Dutch Wechsler Memory Scale - Fourth Edition (WMS-IV-NL) in patients with temporal lobe epilepsy (TLE). METHOD The sample consisted of 75 patients with intractable TLE, who were eligible for epilepsy surgery, and 77 demographically matched healthy controls. All participants were examined with the WMS-IV-NL. RESULTS Patients with TLE performed significantly worse than healthy controls on all WMS-IV-NL indices and subtests (p<.01), with the exception of the Visual Working Memory Index including its contributing subtests, as well as the subtests Logical Memory I, Verbal Paired Associates I, and Designs II. In addition, patients with mesiotemporal abnormalities performed significantly worse than patients with lateral temporal abnormalities on the subtests Logical Memory I and Designs II and all the indices (p<.05), with the exception of the Auditory Memory Index and Visual Working Memory Index. Patients with either a left or a right temporal focus performed equally on all WMS-IV-NL indices and subtests (F(15, 50)=.70, p=.78), as well as the Auditory-Visual discrepancy score (t(64)=-1.40, p=.17). CONCLUSION The WMS-IV-NL is capable of detecting memory problems in patients with TLE, indicating that it is a sufficiently valid memory battery. Furthermore, the findings support previous research showing that the WMS-IV has limited value in identifying material-specific memory deficits in presurgical patients with TLE.

Confirmatory Factor Analysis of the Dutch Version of the Wechsler Memory Scale-Fourth Edition (WMS-IV-NL)

The latent factor structure of the Dutch version of the Wechsler Memory Scale-Fourth Edition (WMS-IV-NL) was examined with a series of confirmatory factor analyses. As part of the Dutch standardization, 1,188 healthy participants completed the WMS-IV-NL. Four models were tested for the Adult Battery (16-69 years; N = 699), and two models were tested for the Older Adult Battery (65-90 years; N = 489). Results corroborated the presence of three WMS-IV-NL factors in the Adult Battery consisting of Auditory Memory, Visual Memory, and Visual Working Memory. A two-factor model (consisting of Auditory Memory and Visual Memory) provided the best fit for the data of the Older Adult Battery. These findings provide evidence for the structural validity of the WMS-IV-NL, and further support the psychometric integrity of the WMS-IV.

Indicators of suboptimal performance embedded in the Wechsler Memory Scale-Fourth Edition (WMS-IV)

ABSTRACT Introduction. Recognition and visual working memory tasks from the Wechsler Memory Scale–Fourth Edition (WMS–IV) have previously been documented as useful indicators for suboptimal performance. The present study examined the clinical utility of the Dutch version of the WMS–IV (WMS–IV–NL) for the identification of suboptimal performance using an analogue study design. Method. The patient group consisted of 59 mixed-etiology patients; the experimental malingerers were 50 healthy individuals who were asked to simulate cognitive impairment as a result of a traumatic brain injury; the last group consisted of 50 healthy controls who were instructed to put forth full effort. Results. Experimental malingerers performed significantly lower on all WMS–IV–NL tasks than did the patients and healthy controls. A binary logistic regression analysis was performed on the experimental malingerers and the patients. The first model contained the visual working memory subtests (Spatial Addition and Symbol Span) and the recognition tasks of the following subtests: Logical Memory, Verbal Paired Associates, Designs, Visual Reproduction. The results showed an overall classification rate of 78.4%, and only Spatial Addition explained a significant amount of variation (p < .001). Subsequent logistic regression analysis and receiver operating characteristic (ROC) analysis supported the discriminatory power of the subtest Spatial Addition. A scaled score cutoff of <4 produced 93% specificity and 52% sensitivity for detection of suboptimal performance. Conclusion. The WMS–IV–NL Spatial Addition subtest may provide clinically useful information for the detection of suboptimal performance.

AVALIAÇÃO DA MEMÓRIA DE TRABALHO VERBAL E VISUOESPACIAL NO COMPROMETIMENTO COGNITIVO LEVE E NA DOENÇA DE ALZHEIMER

In addition to episodic memory impairment, working memory may also be compromised in mild cognitive impairment (MCI) or Alzheimers dementia (AD), but standard verbal and visuospatial span tasks do not always detect impairments. Objective To examine whether more complex verbal and visuospatial working memory tasks result in more reliable impairment detection. Methods The Digit Span (forward, backward and sequencing), Spatial Span (forward and backward) and Spatial Addition test from the Wechsler batteries were administered to MCI and AD patients and performance compared to healthy older adult controls. Results Results showed that both the MCI and AD patients had impaired performance on the Spatial Addition test. Both groups also had impaired performance on all three Digit Span conditions, but no differences were found between forward and backward conditions in any of the groups. The sequencing condition differed from the backward condition only in the AD group. Spatial Span performance was impaired in AD group patients but not in MCI patients. Conclusion Working memory deficits are evident in MCI and AD even on standard neuropsychological tests. However, available tests may not detect subtle impairments, especially in MCI. Novel paradigms tapping the episodic buffer component of working memory may be useful in the assessment of working memory deficits, but such instruments are not yet available for clinical assessment.

Clinical validation of three short forms of the Dutch Wechsler Memory Scale-Fourth Edition (WMS-IV-NL) in a mixed clinical sample.

The reliability and validity of three short forms of the Dutch version of the Wechsler Memory Scale–Fourth Edition (WMS-IV-NL) were evaluated in a mixed clinical sample of 235 patients. The short forms were based on the WMS-IV Flexible Approach, that is, a 3-subtest combination (Older Adult Battery for Adults) and two 2-subtest combinations (Logical Memory and Visual Reproduction and Logical Memory and Designs), which can be used to estimate the Immediate, Delayed, Auditory and Visual Memory Indices. All short forms showed good reliability coefficients. As expected, for adults (16-69 years old) the 3-subtest short form was consistently more accurate (predictive accuracy ranged from 73% to 100%) than both 2-subtest short forms (range = 61%-80%). Furthermore, for older adults (65-90 years old), the predictive accuracy of the 2-subtest short form ranged from 75% to 100%. These results suggest that caution is warranted when using the WMS-IV-NL Flexible Approach short forms to estimate all four indices.

Evidence-based neuropsychologische diagnostiek

Wetenschappelijk opgeleide psychologen moeten in staat zijn te werken als zogenoemde scientist-practitioners. Dat wil zeggen dat zij moeten kunnen reflecteren op hun klinisch handelen en dat hun klinisch handelen gebaseerd is op wetenschappelijke kennis. In dit hoofdstuk zal worden toegelicht wat wordt bedoeld met evidence-based klinische neuropsychologie (EBKNP). Hierbij zal, gezien de onderwerpen van dit boek, de nadruk liggen op de psychodiagnostiek. Specifiek zal worden ingegaan op de wijze waarop EBKNP kan worden toegepast bij individuele casussen. Hierbij is het formuleren van een hypothesetoetsende vraagstelling het uitgangspunt voor de kwantitatieve en kwalitatieve interpretatie van de onderzoeksgegevens. Er wordt een voorbeeld uitgewerkt over de casusgerichte toepassing aan de hand van de statistische interpretatie van het Kort Cognitief Functieonderzoek (KCF) uit de Wechsler Memory Scale-IV-NL (WMS-IV-NL).

Temporal Stability of the Dutch Version of the Wechsler Memory Scale—Fourth Edition (WMS-IV-NL)

Objective: The Wechsler Memory Scale—Fourth Edition (WMS-IV) is one of the most widely used memory batteries. We examined the test–retest reliability, practice effects, and standardized regression-based (SRB) change norms for the Dutch version of the WMS-IV (WMS-IV-NL) after both short and long retest intervals. Method: The WMS-IV-NL was administered twice after either a short (M = 8.48 weeks, SD = 3.40 weeks, range = 3–16) or a long (M = 17.87 months, SD = 3.48, range = 12–24) retest interval in a sample of 234 healthy participants (M = 59.55 years, range = 16–90; 118 completed the Adult Battery; and 116 completed the Older Adult Battery). Results: The test–retest reliability estimates varied across indexes. They were adequate to good after a short retest interval (ranging from .74 to .86), with the exception of the Visual Working Memory Index (r = .59), yet generally lower after a long retest interval (ranging from .56 to .77). Practice effects were only observed after a short retest interval (overall group mean gains up to 11 points), whereas no significant change in performance was found after a long retest interval. Furthermore, practice effect-adjusted SRB change norms were calculated for all WMS-IV-NL index scores. Conclusions: Overall, this study shows that the test–retest reliability of the WMS-IV-NL varied across indexes. Practice effects were observed after a short retest interval, but no evidence was found for practice effects after a long retest interval from one to two years. Finally, the SRB change norms were provided for the WMS-IV-NL.