Standardized Difference Scores Research Articles

Discordance between Adolescents and Parents in Functional Somatic Symptom Reports: Sex Differences and Future Symptom Prevalence

Functional somatic symptoms, i.e., physical complaints that cannot be sufficiently explained by an objectifiable biomedical abnormality, become increasingly more prevalent in girls than in boys during adolescence. Both parents and adolescents report more functional somatic symptoms in girls, but their reports correspond only limitedly. It remains unknown whether parent-adolescent discordance contributes to the higher symptom prevalence in girls. This study investigated parent-adolescent discordance in reported functional somatic symptoms throughout adolescence, examined the longitudinal association of parent-adolescent discordance with symptom prevalence in early adulthood and focused on sex differences in these processes. Participants included 2229 adolescents (50.7% female) from four assessments (age 11 to 22 years) of the TRAILS population cohort. Parents and adolescents reported significantly more symptoms in girls than in boys during adolescence. Variance analyses showed that throughout adolescence, parents reported fewer symptoms than girls self-reported and more than boys self-reported. Regression analyses using standardized difference scores showed that lower parent-report than self-report was positively associated with symptom prevalence in early adulthood. Polynomial regression analyses revealed no significant interaction between parent-reported and adolescent self-reported symptoms. Associations did not differ between boys and girls. The findings show that lower parent-reported than self-reported symptoms predict future symptom prevalence in both sexes, but this discordance was more observed in girls. The higher functional somatic symptom prevalence in girls might be partly explained by parental underestimation of symptoms.

Reliable change and the reliable change index: still useful after all these years?

AbstractIn 1984 Jacobson and colleagues introduced the concept of reliable change, viz the amount of change on a measure that an individual needed to show to determine that it exceeded the extent of change likely due to measurement error alone. Establishing reliable change was a pre-requisite for determining clinical significance. This paper summarizes the rationale for determining reliable change as providing an individual-focused, idiographic alternative to the dominant nomothetic approach to clinical outcome research based on group mean data and statistical significance. The conventional computational steps for calculating an individual’s standardized difference (reliable change) score and the minimum raw change score on the measure (a reliable change index) required to classify individuals as reliably positively changed, indeterminate, or reliably deteriorated are described. Two methods for graphically representing reliable change are presented, and a range of possible uses in both research and practice settings are summarized. A number of issues and debates concerning the calculation of reliable change are reviewed. It is concluded that the concept of reliable change remains useful for both cognitive behavioural researchers and practitioners, but that there are options regarding methods of computation. In any use of reliable change, the rationale for selecting among method options and the exact computations used need clear and careful description so that we can continuously judge the utility and appropriateness of the use of reliable change and enhance its value to the field.Key learning aims(1)Recognizing why the concept of reliable change and the reliable change index is still important.(2)Understanding the conventional formulas for calculating reliable change and the reliable change index (the Jacobson-Truax (JT) method).(3)Seeing key ways that both researchers and practitioners can use reliable change to improve both research and practice.(4)Understanding how several issues and debates that have arisen concerning the estimation of reliable change (e.g. how to accommodate practice effects) have progressed.(5)Recognizing that there are a range of ways that reliable change may be estimated, and the need to provide full details of the method used in any particular instance of its use.

Dissociating disorders of depression, anxiety, and their comorbidity with measures of emotional processing: A joint analysis of visual brain potentials and auditory perceptual asymmetries

In a multigenerational study of families at risk for depression, individuals with a lifetime history of depression had: 1) abnormal perceptual asymmetry (PA; smaller left ear/right hemisphere [RH] advantage) in a dichotic emotion recognition task, and 2) reduced RH late positive potential (P3RH) during an emotional hemifield task. We used standardized difference scores for processing auditory (PA sad-neutral) and visual (P3RH negative-neutral) stimuli for 112 participants (52 men) in a logistic regression to predict history of depression, anxiety or comorbidity of both. Whereas comorbidity was separately predicted by reduced PA (OR = 0.527, p = .042) or P3RH (OR = 0.457, p = .013) alone, an interaction between PA and P3RH (OR = 2.499, p = .011) predicted depressive disorder. Follow-up analyses revealed increased probability of depression at low (lack of emotional differentiation) and high (heightened reactivity to negative stimuli) levels of both predictors. Findings suggest that reduced or heightened right-lateralized emotional responsivity to negative stimuli may be uniquely associated with depression.

An Information-Theoretic Measure for Balance Assessment in Comparative Clinical Studies.

Limitations of statistics currently used to assess balance in observation samples include their insensitivity to shape discrepancies and their dependence upon sample size. The Jensen–Shannon divergence (JSD) is an alternative approach to quantifying the lack of balance among treatment groups that does not have these limitations. The JSD is an information-theoretic statistic derived from relative entropy, with three specific advantages relative to using standardized difference scores. First, it is applicable to cases in which the covariate is categorical or continuous. Second, it generalizes to studies in which there are more than two exposure or treatment groups. Third, it is decomposable, allowing for the identification of specific covariate values, treatment groups or combinations thereof that are responsible for any observed imbalance.

The effect of exercise, yoga and physiotherapy on the quality of life of people with multiple sclerosis: Systematic review and meta-analysis

IntroductionMultiple sclerosis (MS) is a chronic autoimmune disease affecting the myelinated axons of the central nervous system causing neurological deterioration. People living with MS have a poor quality of life (QOL) because of the symptoms caused by the disease and there are various types of treatments to manage the symptoms aside from medication. ObjectiveThis meta-analysis examines the effect of exercise, yoga and physiotherapy on the physical, mental and social QOL among individuals living with MS. SettingA systematic review with meta-analysis was conducted using PubMed, Medline, and Scopus from 1990 to 2017. The standard mean difference scores were computed in each study for the domains of physical, mental and social functioning. ResultsEighteen studies met the inclusion criteria for this meta-analysis. Aerobic exercise was effective in improving satisfaction with physical functioning,d = 0.35 (95% CI = 0.08 to 0.62), mental functioning d = 0.42 (95% CI = 0.11 to 0.72), and social functioning d = 0.42 (95% CI = 0.15 to 0.69). Physiotherapy was also found to be effective for physical functioning d = 0.50 (95% CI 0.19 to 0.80), mental functioning d = 0.44 (95% CI 0.14 to 0.75) and social functioning d = 0.60 (95% CI 0.21 to 0.90). However yoga and combination of exercises did not have a significant effect on any of the QOL domains. ConclusionThese findings suggest that aerobic exercise and physiotherapy improves the satisfaction of MS patients with their physical, mental and social functioning and may be included as normal practice in the treatment of MS.

How predictive are sex and empathizing-systemizing cognitive style for entry into the academic areas of social or physical sciences?

Based on the Empathizing-Systemizing (E-S) theory, it was hypothesized that the underrepresentation of female students in the physical sciences and the underrepresentation of males in the social sciences relates to differences in E-S cognitive style between the sexes. This hypothesis was tested in 115 physical science students and 155 social science students from a university in the Netherlands. The students completed visuospatial tests and the systemizing quotient-revised (SQ-R) as measures for systemizing, and a Cartoon Prediction test and the empathy quotient (EQ) as measures for empathizing. Independent of sex, the physical science students scored significantly lower than social science students on EQ (with large effect size) and 'brain type' that represents the standardized difference score between EQ and SQ-R (with large effect size). Physical science students, furthermore, scored significantly higher on the Cartoon Prediction task and one of the visuospatial tasks; however, these effects were only small of size. Unlike the scores on the SQ-R and the performance tests, the 'brain type' score of the EQ and SQ-R questionnaires was a good predictor of entry into social or physical sciences. Interestingly, the typical sex differences in more empathizing and less systemizing in females compared to males were only small for EQ and 'brain type', and absent for the SQ-R and the performance tests. This study only partially confirms the E-S theory, because typical sex differences were only minor in this selective sample and only the self-report measures predicted academic area in the absence of a role for sex.

Parent-adolescent concordance on the Revised Diagnostic Interview for Borderlines (DIB-R) and the Childhood Interview for Borderline Personality Disorder (CI-BPD).

While the degree of concordance between parent and adolescent self-report of internalizing and externalizing pathology is well studied, virtually nothing is known about concordance in borderline pathology and the implication of parent-adolescent discrepancies for outcomes. The present study aimed to (1) examine discrepancies between parents and adolescents on two interview-based measures of borderline personality disorder (BPD)-the Revised Diagnostic Interview for Borderlines (DIB-R22 ) and the Childhood Interview for Borderline Personality Disorder (CI-BPD23 ); and (2) investigate the implications of discrepancies for clinical outcomes. Diagnostic concordance on the DIB-R and CI-BPD showed rates of 82% and 94% respectively, with lower concordance demonstrated for dimensionally scored variables. Standardized difference scores between adolescent and parent reports on both borderline measures were significantly correlated with few interview-based axis I diagnoses as reported by parents, but not adolescents themselves. Implications regarding the use of each measure for the assessment and diagnosis of borderline personality disorder are discussed. Copyright © 2017 John Wiley & Sons, Ltd.

Abstract MP019: Contributors to the Black-White Disparities in Incident Hypertension

Introduction: While predictors of incident hypertension are well-studied, the factors explaining the black-white (B/W) disparity in the incidence of hypertension are unknown. Absent interactions, for a factor to contribute to this racial disparity, it must both : 1) have a large B/W difference in prevalence, and 2) be strongly associated with the risk of incident hypertension. Methods: We selected 20 established risk factors for hypertension to assess the degree to which they contribute to the black excess risk of incident hypertension. The B/W difference in hypertension risk factors was assessed by the standardized difference score (SDS: # standard errors difference in the B/W means) adjusting for age group. The impact of risk factors on incident hypertension was assessed by logistic regression adjusting for age group and baseline SBP. The mediation by each risk factor was calculated as the percent change in the regression coefficient for black race with additional adjustment for each risk factor. Results: Over a 10-year follow-up, 45% of 619 black and 36% of 2204 white men, and 52% of 994 black and 34% of 2409 white women, developed hypertension. The B/W difference in the mean southern diet score (assessed by a food frequency survey) was large for men (SDS =19.3) and women (SDS = 21.8). The diet score was also strongly associated with incident hypertension for men (OR = 1.17; 95% CI: 1.07-1.30) and women (OR = 1.18; 95% CI: 1.06-1.30). As such, the diet score was the most powerful mediator of the B/W difference in incident hypertension, accounting for 52% (95% CI: 19%-84%) of the black excess risk in men and 26% (95%CI: 10%-42%) in women. For women, BMI was the 2 nd most powerful mediator, accounting for 17% (95% CI: 6% - 15%) of the excess black risk of hypertension (SDS = 9.5; OR = 1.04; 95% CI: 1.03-1.06); however, because BMI was similar in black and white men (SDS = 1.4) it did not significantly mediate the risk in men (p = 0.63). Low education was the 2 nd most powerful mediator for men (14%: 95% CI: 3%-25%), but played a smaller role in women (4% mediation; 95% CI: 2% - 7%) because of a smaller B/W difference of the prevalence of low education in women (SDS = 1.4). The dietary sodium/potassium ratio (11%) was also a mediator in men; while in women (in decreasing order of mediation) low mobility (15%), low DASH diet score (11%), low income (10%), low neighborhood quality (8%), dietary sodium/potassium ratio (5%), low physical activity (5%) and low education (4%) also contributed to the excess black risk of incident hypertension. Other factors including exercise and discrimination did not significantly mediate the excess risk of hypertension in blacks. Conclusions: This report provides insights to the contributors of the higher incidence of hypertension in blacks, with a high consumption of southern foods being the most powerful contributor to black disparity in incidence of hypertension for both men and women.

A genetic marker of risk in HIV-infected individuals with a history of hazardous drinking

ABSTRACTImpulsivity and sensation seeking have been linked to hazardous drinking, increased sexual risk behaviors, and lower treatment adherence among persons living with HIV (PLH). The dopamine active transporter1 (DAT1or SLC6A3) gene has been linked to impulsivity and sensation seeking in several populations but has not been investigated among populations of PLH. This study used data from 201 PLH who report a recent history of heavy episodic drinking. Results indicate that DAT1*10R vs DAT1*9R genotype was related to higher propensity for risk taking (standardized difference score (d) = 0.30 [95% CI: 0.02;0.59]), more hazardous drinking (d = 0.35 [0.05;0.64]), and more condomless sex (rate ratio (RR)= 2.35[1.94; 2.85]), but were counter-intuitively associated with fewer sexual partners (RR = 0.65[0.43;0.91]) and possibly better treatment adherence (d = 0.32 [−0.01;0.65]). Results are consistent with the suggested associations between DAT1 and risk-taking behavior. The counter-intuitive finding for partner selection and treatment adherence may be evidence of additional factors that place PLH at risk for engaging in hazardous drinking as well as relationship difficulties and problems with treatment adherence (e.g., depressive symptoms, avoidant coping, trauma history). Caution is required when using a single gene variant as a marker of complex behaviors and these findings need to be replicated using larger samples and additional variants.

Aided cortical response, speech intelligibility, consonant perception and functional performance of young children using conventional amplification or nonlinear frequency compression

ObjectiveThe aim of this study was to compare conventional processing with nonlinear frequency compression (NLFC) in hearing aids for young children with bilateral hearing loss. MethodsSixty-four children aged between 2 and 7 years with bilateral hearing aids were recruited. Evaluations of cortical responses, speech intelligibility rating, consonant perception and functional performance were completed with the children wearing their personal hearing aids with conventional processing. The children were then refitted with new hearing aids with NLFC processing. Following a six-week familiarization period, they were evaluated again while using their hearing aids with NLFC activated. ResultsThe mean speech intelligibility rating and the number of cortical responses present for /s/were significantly higher when children were using NLFC processing than conventional processing in their hearing aids (p<0.05). Parents judged the children's functional real life performance with the NLFC hearing aids to be similar or better than that with the children's own hearing aids in both quiet and noisy situations. The mean percent consonant score was higher with NLFC processing compared to conventional processing, but the difference did not reach the 5% significance level (p=0.056). An overall figure of merit (FOM) was calculated by averaging the standardized difference scores between processing schemes for all measures. Regression analysis revealed that, on average, greater advantage for NLFC processing was associated with poorer hearing at 4kHz. ConclusionsCompared to conventional processing, the use of NLFC was, on average, effective in increasing audibility of /s/as measured by cortical evaluations, and higher ratings on speech intelligibility and functional performance in real life by parents. On average, greater benefits from NLFC processing was associated with poorer hearing at 4kHz.

Do Parents and Children Agree? Quality‐of‐Life Assessment of Children With Inflammatory Bowel Disease and Their Parents

Multi-item measures of inflammatory bowel disease (IBD) activity based on clinical, laboratory, and/or endoscopic variables do not take into consideration the impact on the patients' emotional aspects and adaptation to the disease. The aim of the present study was to evaluate concordance between parent and child ratings of health-related quality of life on the IMPACT-III questionnaire in children with IBD. The IMPACT-III questionnaire was used to measure quality of life in 27 patients (mean age 14.2 ± 3 years, 40% girls) and one of their parents (82% mothers). Most of the patients had inactive disease at the time of the study. Differences between parent-proxy ratings and child ratings on the IMPACT-III were compared via paired-samples t tests, intraclass correlation coefficients, and standardized difference scores. Parent-proxy and patient ratings were similar on total IMPACT-III and its related domains (bowel symptoms, systemic symptoms, social functioning, body image, treatment/interventions), except that significant differences on emotional functioning ratings were found (P = 0.003). Intraclass correlation coefficients showed medium-to-large effect sizes (range 0.52-0.88) and standardized difference scores showed varying degrees of bias depending on the domain measured (range -0.64 to 0.32). Parents served as a good proxy for quality-of-life ratings in this population of pediatric patients with IBD. The degree of concordance between parent and child scores, however, varied, as observed in the present study in which parents underreported their child's health-related quality of life on the IMPACT-III emotional functioning domain.

The relevance of informant discrepancies for the assessment of adolescent personality pathology.

In this article, we compare the nature and function of self-parent informant discrepancies for adolescent personality pathology using two methods: standard difference scores (SDS) and polynomial regressions. In total, 489 11- to 18-year-old youth (54% female) and their parents reported on youth personality pathology traits and general psychopathology. Findings supported convergence and divergence in parent- and self-reports. Potential utility of informant discrepancies also emerged, such that discrepancies on trait disagreeableness and trait compulsivity predicted youth externalizing problems using the SDS approach and the polynomial regression approach; however, the polynomial regression approach yielded a more complex and nuanced characterization of informant discrepancies than did the SDS approach. Taken together, these results suggest that polynomial regressions may provide a more comprehensive picture regarding the meaning and utility of informant discrepancies.

A Concealed Information Test with Combination of ERP Recording and Autonomic Measurements

The concealed information test (CIT) is based on a comparison between the subject’s physiological responses to a probe and irrelevant items in order to detect concealed information. The main purpose of our study was to investigate the CIT accuracy enhancement related to a combination of recording of event-related potentials (ERPs) and autonomic measurements. We tried to maximally liken the experimental conditions to real ones by the use of a criminal context in the “mock crime” instruction and real innocent subjects instead of hypothetical ones. Fifty-two subjects volunteered and performed just one of the innocent or guilty scenarios. The CIT was designed in five blocks with short interstimulus intervals. In each block, stimuli were presented in the 7th-order balanced sequence. In addition to EEG phenomena, the heart rate, skin conductance responses (SCRs), respiratory activity, and finger plethysmogram were recorded. Statistical analyses showed that there was a significant difference between standardized difference scores of the guilty and innocent groups in both ERP and autonomic measures. The SCR did not achieve the expected results reported in standard autonomic-based CIT studies. A review of the two classification methods showed that the combination of ERP and autonomic measurements enhances the CIT accuracy. The best classification accuracy obtained by the aid of linear discriminant analysis (LDA) was 90.9%. It seems that using a criminal context in the “mock crime” instruction and the reward-punishment system made subjects more attentive and involved in the experiment; therefore, the accuracy was improved compared with that in similar studies.

The Standard Difference Score: A New Statistic for Evaluating Strength and Conditioning Programs

Inferential statistics help the strength and conditioning specialist to determine if a team is responding to a strength and conditioning program overall; however, such statistics do not detect unusual responses among individuals such as those who may be overtraining. This article introduces the standard difference score (SDS), a new statistic for evaluating strength and conditioning programs. The SDSs are standard scores (z score) derived from a change in a raw strength and conditioning performance score. They are simple to calculate and sort, easy to plot, and can be aggregated to detect athletes exhibiting extreme performance changes from a battery of tests. Standard difference scores, when evaluated with skewness, can be substituted for conventional exploratory statistics generated with higher end statistical software programs.

A cross-over, double-blind comparison of the NAL-NL1 and the DSL v4.1 prescriptions for children with mild to moderately severe hearing loss

The relative effectiveness of the NAL-NL1 and the DSL4.1 prescriptions for 48 children with mild to moderately severe hearing loss was studied using a double-blind, four-period, two-treatment cross-over design in Australia and in Canada. Evaluations included speech perception tests, loudness ratings, reports from parents and teachers on functional performance in real life, children's self-reports, paired-comparison judgements of intelligibility, and children's preferences in real-world environments. Electroacoustic measures of hearing aids revealed that gain differences dominated the comparison. Across trials and measures, individual Australian children consistently preferred either the NAL-NL1 or the DSL v.4.1 prescription. An overall figure of merit (FOM), calculated by averaging the standardized difference scores between prescriptions for all measures, revealed that the strongest prescription-related differences were found in Australia. On average, an advantage and preference for the NAL-NL1 prescription was associated with lesser degrees of hearing loss. This research provides evidence on the effectiveness of the NAL-NL1 and DSL v.4.1 prescriptions, and highlights the need for evaluating and fine-tuning amplification to meet the diverse needs of individual children in real life.SumarioSe estudió la relativa efectividad de las prescripciones NAL-NL1 y DSL 4.1 en 48 niños con pérdidas auditivas de leves a moderadamente severas, usando un estudio doble ciego, en cuatro períodos y con un diseño cruzado de dos tratamientos en Australia y en Canadá. Las evaluaciones incluyeron pruebas de percepción de la palabra, tasas de reclutamiento, auto-reportes de los niños, juicios de inteligibilidad comparados por pares y preferencias de los niños en ambientes de mundo real. Las mediciones electroacústicas de los auxiliares auditivos revelaron que las diferencias en ganancia dominaron la comparación. En todas las pruebas y mediciones, los niños Australianos individualmente prefirieron de manera consistente tanto la prescripción NAL-NL1 como la DSL v.4.1. Una figura global de mérito (FOM), calculada al promediar las puntuaciones de diferencias estandarizadas entre prescripciones de todas las medidas, revelaron que las diferencias más fuertemente relacionadas con la prescripción, se encontraron en Australia. En promedio, la ventaja y preferencias hacia la prescripción NAL-NL1 se asoció con grados menores de pérdida auditiva. Esta investigación proporciona evidencia de la efectividad de las prescripciones NAL-NL1 y DSL v.4.1 y pone de relieve la necesidad de evaluar y de afinar la amplificación para alcanzar las diversas necesi-dades individuales de los niños en la vida real.

Identifying the Unauthorized Use of Examination Material

Item disclosure is one of the most serious threats to the validity of high stakes examinations, and identifying examinees that may have had unauthorized access to material is an important step in ensuring the integrity of an examination. A procedure was developed to identify examinees that potentially had unauthorized prior access to examination content. A standardized difference score is created by comparing examinee ability estimates for potentially exposed items to ability estimates for unexposed items. Outliers in this distribution are then flagged for further review. The steps associated with this procedure are described and followed by an example of applying the procedure. In addition, the use of this procedure is supported by the results of a simulation that models the use of unauthorized access to examination material.

Meta-Analysis of Randomized Response Research

This article discusses two meta-analyses on randomized response technique (RRT) studies, the first on 6 individual validation studies and the second on 32 comparative studies. The meta-analyses focus on the performance of RRTs compared to conventional question-and-answer methods. The authors use the percentage of incorrect answers as effect size for the individual validation studies and the standardized difference score (d-probit) as effect size for the comparative studies. Results indicate that compared to other methods, randomized response designs result in more valid data. For the individual validation studies, the mean percentage of incorrect answers for the RRT condition is .38; for the other conditions, it is .49. The more sensitive the topic under investigation, the higher the validity of RRT results. However, both meta-analyses have unexplained residual variances across studies, which indicates that RRTs are not completely under the control of the researcher.

Longitudinal changes in IQ among fragile X males: clinical evidence of more than one mutation?

Longitudinal changes in IQ among mentally retarded (MR) fragile X [fra(x)] males have been reported previously. While age is associated with decline in IQ, not all males are so affected. This suggests that there may be more than one subtype of affected fra(X) male. Therefore, we examined the distribution of standardized difference scores (Zdiff) in IQ to determine if subjects were from an admixture of at least 2 populations. Cluster analysis of Zdiff scores was used to partition subjects into 2 groups. Goodness-of-fit tests indicated that scores were more likely to come from an admixture. Discriminant functions (DF) were calculated to determine predictive validity of Zdiff scores. To eliminate the effect of skewing, a power transform was applied to Zdiff scores and DFs recomputed. Zdiff and transformed scores provided similar results. The mean and variance for one group showed no differences in test-retest scores as would be expected from examining any population while the mean for the second group indicated significant decline in IQ nearly 4 standard errors below the first test score. These results suggest that there may be clinical evidence for 2 types of fra(X) mutation: One which causes MR but is static, and a second mutation which causes MR but is dynamic and contributes to an apparent longitudinal decline in cognitive function.

Postherpetic Neuralgia and Systemic Corticosteroid Therapy

Corticosteroids are frequently advocated for use in prevention of postherpetic neuralgia (PHN), although their use is replete with controversy. The present study is a meta-analysis of the four well-controlled clinical studies conducted on this issue. The results indicated there is a statistically significant decrease in proportions affected at 6 and 12 weeks. Standard difference scores were -2.0559 and -4.1442, respectively, and 95% confidence intervals were -3.98% to -31.80% and -14.16% to -43.84%, respectively. At 24 weeks, no differences were detectable between placebo- and corticosteroid-treated groups (SD = 0.6603, p greater than 0.05, 95% confidence intervals of -6.78% to 24.67%). Side effects of treatment were rare and mild, affecting only 2.5% of patients treated with corticosteroids. No patients had dissemination of disease. Systemic corticosteroid treatment decreases the proportion of patients affected by PHN, especially when it is defined as pain occurring at 6 or 12 weeks after the acute event.

Lateralized Brain Dysfunction in Depression: Analysis of Memory

This study was designed to investigate the hypothesized association between non-dominant hemispheric dysfunction and depressive illness. Twenty-eight depressed inpatients, fourteen nonpsychiatric controls, and one right temporal lesioned control were administered both a verbal and visual list learning task with restrictive reminding. Each test consisted of four recall trials (employing a percent correct measure) and two recognition probes (employing a d' measure). Items to be remembered were names of animals on the verbal task and moderately complex designs on the visual task. Standardized difference scores (verbal-visual) were determined to control for motivational confounds and individual performance levels.