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Mats NajströmUniversitetslektor, leg. psykolog leg. psykoterapeut

Publikationer

I urval från Stockholms universitets publikationsdatabas

  • WAIS-IV short form applied to a mixed neurological Swedish clinical sample

    2021. Maria Lindau, Milena Lundberg, Mats Najström. Nordic Psychology

    Artikel

    The Wechsler Adult Intelligence Scale, fourth version (WAIS-IV), is a frequently used instrument for neuropsychological assessment. The aim was to assess the degree of conformity between the Scandinavian adaptation of the WAIS-IV and a short form of this scale (SF) in a mixed sample of neurological diagnoses. The SF comprised Block Design, Similarities, Digit Span, Arithmetic, Information, Digit Symbol (in the WAIS-IV named Coding), and Picture Completion, the latter here replaced by Matrix Reasoning. The sample consisted of 150 patients and included multiple sclerosis (n = 27), brain tumor (n = 15), traumatic brain injury (n = 60) and vascular brain damage (n = 48). There was a lack of congruence between the WAIS-IV and the SF in the entire sample, revealing selectively significantly higher scores for the SF on Full Scale IQ (FSIQ) and Processing Speed Index (PSI). On a diagnostic group level, the discrepancies were as follows: in the traumatic brain injury group on FSIQ, Verbal Comprehension Index (VCI) and PSI, in the vascular damage group the FSIQ was significantly higher on SF compared to the WAIS-IV. Since the results revealed several mismatches between the SF and the WAIS-IV, except for the MS and traumatic brain tumor group, there is a lack of interchangeability between these two sets of tests. Thus, generally the SF cannot be recommended as a substitute for the WAIS-IV in this type of mixed Swedish neurological sample. The small sample sizes make the generalizability of this study limited.

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  • Cross-cultural applicability and reduction of the American seven-subtest short form of the WAIS on a Swedish non-clinical sample

    2019. Maria Lindau, Mats Najström. Nordic Psychology 71 (3), 148-163

    Artikel

    The study aimed at investigating whether the seven-subtest short form based on WAIS-R (Ward 1990) was statistically valid to use on the Swedish version of Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV), if this abbreviation was fit to catch the heterogeneity in test performance across age and if this brief measure was possible to abbreviate even more. WAIS-IV data from a non-clinical sample consisting of 261 participants ranging between 18 and 74 in age was analyzed with bivariate and multiple regression analyses, a prorating method for calculation of Full Scale IQ (FSIQ) and its indices as well as paired-samples t-test. The results were contradictory. When the original WAIS-IV was compared to the seven-subtest short form the results showed a good congruence on FSIQ-level between the two sets, but on index level there were several cases of mismatches. In the younger and middle aged sample (<55 years) results on FSIQ as well as index level were in accordance, whereas in the elderly group (∼55 years) they were incongruent. The best reduction of the seven-subtest short form was a four-subtest model, encompassing Block Design, Similarities, Arithmetic and Coding, one subtest from each index, but the t-tests indicated several cases of mismatches between the full WAIS-IV measures and the prorated scores. Applied on the Swedish version of the WAIS-IV the seven-subtest formula appears to be applicable on an FSIQ level, to be suitable for a younger sample, but not for an elderly. Otherwise, this model and the four-subtest model are recommended to be used with caution.

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  • Predictive accuracy of Wechsler Adult Intelligence Scale, forth ed., (WAIS-IV) seven- and four- subtest short form models in estimating full scale IQ (FSIQ) and its indices in a Swedish non-clinical sample

    2016. Maria Lindau, Mats Najström. Proceedings of 4th Global Experts Meeting on Neuropharmacology

    Konferens

    Neurodegenerative disorders usually show characteristic cognitive profiles, determined by the anatomical dispersion of neuronal loss. Short-term/memory decline is a presenting symptom on Alzheimer’s disease, but atypical early signs also occur. The Wechlser Adult Intelligence Scale (WAIS) may be used to differentiate between normal and sub-normal cognitive performance levels, such as pre-dementia stages, AD and related disorders. According to Meyers et al., (2013), a brief measure consisting of a seven-subtest short form (SF) of the WAIS-IV including Block Design (BD), Similarities (SI), Digit Span (DS), Arithmetic (AR), Information (IN) Coding (CD) and Picture Completion (PC) provides a valid means of measuring cognitive level. In order to validate a short form of WAIS-IV on a Swedish non-clinical sample the aim of the present study was to assess the ability of the seven-subtest SF as well as a reduction of the number of subtests in the SF based on standardized β-values, to predict the full scale IQ (FSIQ) and its indices. WAIS-IV scaled score data from 98 healthy individuals (19-90 years M=46 years, SD=23 years, females=48, males=50) were analyzed with linear regression, which showed that the seven predictors explained 92.5% of the variance in FSIQ. When reducing the SF-set the four highest β-values were obtained from the following subtests: CD, β=0.34 (Processing Speed), SI, β=0.31 (Verbal Comprehension), BD, β=0.25 (Perceptual Reasoning), and AR, β=0.23 (Working memory), which showed to be one subtest from each of the four indices. FSIQ prediction rate of these four subtests was 88.1%. Each of the four subtests correlated significantly on p=<0.01 level with its index. To conclude, FSIQ prediction accuracy for the seven-subtest SF is very high, as well as for the four-subtest model. Since the four-subtest model strongly predicts FSIQ, as well as all its indices, it may be a valid, and timesaving, instrument to assess short-term memory (AR, partly CD) deficits typical for different stages of AD, signs on non-amnestic decline in AD, as well as typical clinical manifestations of frontotemporal degeneration, Parkinson’s disease, Lewy body disease, ischemic brain disorders and cognitive dysfunctions associated with depression. In unclear cases additional testing is necessary. Further analyses will reveal possible influences on the norms of age, genus and education.

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  • Is preattentive bias predictive of autonomic reactivity in response to a stressor?

    2009. Billy Jansson, Mats Najström. Journal of Anxiety Disorders 23 (3), 374-380

    Artikel

    Biased processing of threatening information may play a casual role in the development of anxiety disorders. Even though empirical evidence points to the fact that preattentive bias can predict subjectively experienced distress in response to a stressor, it is still unknown whether it could be useful in predicting the physiological reactivity in response to a stressor. In the present study, the emotional Stroop task was used to measure preattentive bias. Whereas Stroop interference for masked threat words (i.e., preattentive bias) was found to be positively associated with emotional distress (self-reported) in response to a laboratory stressor, this association was reversed when the autonomic reactivity (electrodermal activity) was used as a measure of emotional response to the very same stressor. Also, neither of these effects were a function of pre-existing anxiety levels. The negative association between preattentive bias and autonomic reactivity corresponds to the autonomic inflexibility seen in clinical anxiety (or very high scores of trait anxiety) when exposed to stressful events. Results were discussed in terms of an inability to automatically inhibit the processing of threatening cues that seems to be a vulnerability marker for anxiety.

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