Objectives: Elevated body mass index (BMI) is associated with deficits in working memory, reduced gray matter volume in frontal and parietal lobes, as well as changes in white matter (WM) microstructure. The current study examined whether BMI was related to working memory performance and blood oxygen level dependent (BOLD) activity, as well as WM microstructure during adolescence. Methods: Linear regressions with BMI and (1) verbal working memory BOLD signal, (2) spatial working memory BOLD signal, and (3) fractional anisotropy (FA), a measure of WM microstructure, were conducted in a sample of 152 healthy adolescents ranging in BMI. Results: BMI was inversely related to IQ and verbal and spatial working memory accuracy; however, there was no significant relationship between BMI and BOLD response for either verbal or spatial working memory. Furthermore, BMI was negatively correlated with FA in the left superior longitudinal fasciculus (SLF) and left inferior longitudinal fasciculus (ILF). ILF FA and IQ significantly mediated the relationship between BMI and verbal working memory performance, whereas SLF FA, but not IQ, significantly mediated the relationship between BMI and accuracy of both verbal and spatial working memory. Conclusions: These findings indicate that higher BMI is associated with decreased FA in WM fibers connecting brain regions that support working memory, and that WM microstructural deficits may underlie inferior working memory performance in youth with higher BMI. Of interest, BMI did not show the same relationship with working memory BOLD activity, which may indicate that changes in brain structure precede changes in function. (JINS, 2015, 21, 281–292)

Objectives: Decrements in cognitive function may already be evident in young children with type 1 diabetes (T1D). Here we report prospectively acquired cognitive results over 18 months in a large cohort of young children with and without T1D. Methods: A total of 144 children with T1D (mean HbA1c: 7.9%) and 70 age-matched healthy controls (mean age both groups 8.5 years; median diabetes duration 3.9 years; mean age of onset 4.1 years) underwent neuropsychological testing at baseline and after 18-months of follow-up. We hypothesized that group differences observed at baseline would be more pronounced after 18 months, particularly in those T1D patients with greatest exposure to glycemic extremes. Results: Cognitive domain scores did not differ between groups at the 18 month testing session and did not change differently between groups over the follow-up period. However, within the T1D group, a history of diabetic ketoacidosis (DKA) was correlated with lower Verbal IQ and greater hyperglycemia exposure (HbA1c area under the curve) was inversely correlated to executive functions test performance. In addition, those with a history of both types of exposure performed most poorly on measures of executive function. Conclusions: The subtle cognitive differences between T1D children and nondiabetic controls observed at baseline were not observed 18 months later. Within the T1D group, as at baseline, relationships between cognition (Verbal IQ and executive functions) and glycemic variables (chronic hyperglycemia and DKA history) were evident. Continued longitudinal study of this T1D cohort and their carefully matched healthy comparison group is planned. (JINS, 2016, 21, 293–302)

Objectives: The current study aimed to determine whether reversal learning impairments and feedback-related negativity (FRN), reflecting reward prediction error signals generated by negative feedback during the reversal learning tasks, were associated with social disinhibition in a group of participants with traumatic brain injury (TBI). Methods: Number of reversal errors on a social and a non-social reversal learning task and FRN were examined for 21 participants with TBI and 21 control participants matched for age. Participants with TBI were also divided into low and high disinhibition groups based on rated videotaped interviews. Results: Participants with TBI made more reversal errors and produced smaller amplitude FRNs than controls. Furthermore, participants with TBI high on social disinhibition made more reversal errors on the social reversal learning task than did those low on social disinhibition. FRN amplitude was not related to disinhibition. Conclusions: These results suggest that impairment in the ability to update behavior when social reinforcement contingencies change plays a role in social disinhibition after TBI. Furthermore, the social reversal learning task used in this study may be a useful neuropsychological tool for detecting susceptibility to acquired social disinhibition following TBI. Finally, that the FRN amplitude was not associated with social disinhibition suggests that reward prediction error signals are not critical for behavioral adaptation in the social domain. (JINS, 2016, 21, 303–313)

Objectives: Previous evidence indicates that patients with schizophrenia exhibit reduced repetition priming in production tasks (in which each response cue engenders a competition between alternative responses), but not in identification tasks (in which each response cue allows a unique response). However, cross-task comparisons may lead to inappropriate conclusions, because implicit tests vary on several dimensions in addition to the critical dimension of response competition. The present study sought to isolate the role of response competition, by varying the number of solutions in the context of the same implicit tasks. Methods: Two experiments investigated the performance of patients with schizophrenia and healthy controls in the high-competition and low-competition versions of word-stem completion (Exp.1) and verb generation (Exp.2). Results: Response competition affected both the proportions of stems completed (higher to few-solution than to many-solution stems) and the reaction times of verb generation (slower to nouns having no dominant verb associates than to nouns having one dominant verb associate). Patients with schizophrenia showed significant (non-zero) priming in both experiments: crucially, the magnitude of this facilitation was equivalent to that observed in healthy controls and was not reduced in the high-competition versions of the two tasks. Conclusions: These findings suggest that implicit memory is spared in schizophrenia, irrespective of the degree of response competition during the retrieval phase; in addition, they add to the ongoing debate regarding the validity of the identification/production hypothesis of repetition priming. (JINS, 2015, 21, 314–321)

An observational study of neuropsychological outcomes at preschool age of tiered lowered oxygen (O2) saturation targets in extremely preterm neonates. We studied 111 three-year-olds born <28 weeks’ gestational age. Fifty-nine participants born in 2009–2010 during a time-limited quality improvement initiative each received three-tiered stratification of oxygen rates (83–93% until age 32 weeks, 85–95% until age 35 weeks, and 95% after age 35 weeks), the TieredO2 group. Comparisons were made with 52 participants born in 2007–2008 when pre-initiative saturation targets were non-tiered at 89–100%, the Non-tieredO2 group. Neuropsychological domains included general intellectual, executive, attention, language, visuoperceptual, visual-motor, and fine and gross motor functioning. Descriptive and inferential analyses were conducted. Group comparisons were not statistically significant. Descriptively, the TieredO2 group had better general intellectual, executive function, visual-motor, and motor performance and the Non-tieredO2 group had better language performance. Cohen’s d and confidence intervals around d were in similar direction and magnitude across measures. A large effect size was found for recall of digits-forward in participants born at 23 and 24 weeks’ gestation, d=0.99 and 1.46, respectively. Better TieredO2 outcomes in all domains except language suggests that the tiered oxygen saturation target method is not harmful and merits further investigation through further studies. Benefit in auditory attention appeared greatest in those born at 23 and 24 weeks. Participants in the tiered oxygen saturation group also had fewer ventilation days and a lower incidence of bronchopulmonary dysplasia, perhaps explanatory for these neuropsychological outcomes at age 3. (JINS, 2015, 21, 322–331)

Objectives: Hazard perception, the ability to identify and react to hazards while driving, is of growing importance in driving research, given its strong relationship to real word driving variables. Furthermore, although poor hazard perception is associated with novice drivers, recent research suggests that it declines with advanced age. In the present study, we examined the neuropsychological correlates of hazard perception in a healthy older adult sample. Methods: A total of 68 adults age 60 and older who showed no signs of dementia and were active drivers completed a battery of neuropsychological tests as well as a hazard perception task. Tests included the Repeatable Battery for the Assessment of Neuropsychological Status, Wechsler Test of Adult Reading, Trail Making Test, Block Design, Useful Field of View, and the Delis-Kaplan Executive Function System Color Word Interference Test. Results: Hazard perception errors were related to visuospatial/constructional skills, processing speed, memory, and executive functioning skills, with a battery of tests across these domains accounting for 36.7% of the variance in hazard perception errors. Executive functioning, particularly Trail Making Test part B, emerged as a strong predictor of hazard perception ability. Conclusions: Consistent with prior work showing the relationship of neuropsychological performance to other measures of driving ability, neuropsychological performance was associated with hazard perception skill. Future studies should examine the relationship of neuropsychological changes in adults who are showing driving impairment and/or cognitive changes associated with Mild Cognitive Impairment or dementia. (JINS, 2015, 21, 332–340)

Objective: Idiopathic normal pressure hydrocephalus (INPH) is a neurological disorder presenting with gait, cognitive, and bladder symptoms in the context of ventricular enlargement. Although gait is the primary indicator for treatment candidacy and outcome, additional monitoring tools are needed. Line Tracing Test (LTT) and Serial Dotting Test (SDT), two psychomotor tasks, have been introduced as potential outcome measures but have not been widely studied. This preliminary study examined whether LTT and SDT are sensitive to motor dysfunction in INPH and determined if accuracy and time are important aspects of performance. Methods: Eighty-four INPH subjects and 36 healthy older adults were administered LTT and SDT. Novel error scoring procedures were developed to make scoring practical and efficient; interclass correlation showed good reliability of scoring procedures for both tasks (0.997; p<.001). Results: The INPH group demonstrated slower performance on SDT (p<.001) and made a greater number of errors on both tasks (p<.001). Combined Time/Error scores revealed poorer performance in the INPH group for original-LTT (p<.001), modified-LTT (p≤.001) and SDT (p<.001). Conclusions: These findings indicate LTT and SDT may prove useful for monitoring psychomotor skills in INPH. While completion time reflects impaired processing speed, reduced accuracy may suggest planning and self-monitoring difficulties, aspects of executive functioning known to be compromised in INPH. This is the first study to underscore the importance of performance accuracy in INPH and introduce practical/reliable error scoring for these tasks. Future work will establish reliability and validity of these measures and determine their utility as outcome tools. (JINS, 2016, 22, 341–349)

Objectives: We examined performance on the Boston Naming Test (BNT) in older and younger adults who were monolingual English or French speakers, or bilingual speakers of English and French (n=215). Methods: Monolingual participants completed the task in their native language, and bilingual participants completed the task in English, French, and bilingual (either-language) administrations. Results: Overall, younger and older monolingual French speakers performed worse than other groups; bilingual participants performed worst in the French administration and approximately two-thirds of bilingual participants performed better when responses were accepted in either language. Surprisingly, however, a subset of bilinguals performed worse when responses were accepted in either language as compared to their maximum score achieved in either English or French. This either-language disadvantage does not appear to be associated with the degree of balanced bilingualism, but instead appears to be related to overall naming abilities. Differential item analysis comparing language groups and the different administrations identified several items that displayed uniform and/or non-uniform differential item functioning (DIF). Conclusions: The BNT does not elicit equivalent performance in English and French, even when assessing naming performance in monolingual French speakers using the French version of the test. Scores were lower in French overall, and several items exhibited DIF. We recommend caution in interpreting performance on these items in bilingual speakers. Finally, not all bilinguals benefit from an either-language administration of the BNT. (JINS, 2015, 21, 350–363)

Hispanics are the fastest growing ethnicity in the United States, yet there are limited well-validated neuropsychological tools in Spanish, and an even greater paucity of normative standards representing this population. The Spanish NIH Toolbox Cognition Battery (NIHTB-CB) is a novel neurocognitive screener; however, the original norms were developed combining Spanish- and English-versions of the battery. We developed normative standards for the Spanish NIHTB-CB, fully adjusting for demographic variables and based entirely on a Spanish-speaking sample. A total of 408 Spanish-speaking neurologically healthy adults (ages 18–85 years) and 496 children (ages 3–7 years) completed the NIH Toolbox norming project. We developed three types of scores: uncorrected based on the entire Spanish-speaking cohort, age-corrected, and fully demographically corrected (age, education, sex) scores for each of the seven NIHTB-CB tests and three composites (Fluid, Crystallized, Total Composites). Corrected scores were developed using polynomial regression models. Demographic factors demonstrated medium-to-large effects on uncorrected NIHTB-CB scores in a pattern that differed from that observed on the English NIHTB-CB. For example, in Spanish-speaking adults, education was more strongly associated with Fluid scores, but showed the strongest association with Crystallized scores among English-speaking adults. Demographic factors were no longer associated with fully corrected scores. The original norms were not successful in eliminating demographic effects, overestimating children’s performances, and underestimating adults’ performances on the Spanish NIHTB-CB. The disparate pattern of demographic associations on the Spanish versus English NIHTB-CB supports the need for distinct normative standards developed separately for each population. Fully adjusted scores presented here will aid in more accurately characterizing acquired brain dysfunction among U.S. Spanish-speakers. (JINS, 2016, 21, 364–374)

Objectives: The Paced Auditory Serial Addition Test (PASAT) is used to assess cognitive status in multiple sclerosis (MS). Although the mathematical demands of the PASAT seem minor (single-digit arithmetic), cognitive psychology research links greater mathematical ability (e.g., algebra, calculus) to more rapid retrieval of single-digit math facts (e.g., 5+6=11). The present study evaluated the hypotheses that (a) mathematical ability is related to PASAT performance and (b) both the relationship between intelligence and PASAT performance as well as the relationship between education and PASAT performance are both mediated by mathematical ability. Methods: Forty-five MS patients were assessed using the Wechsler Test of Adult Reading, PASAT and Calculation Subtest of the Woodcock-Johnson-III. Regression based path analysis and bootstrapping were used to compute 95% confidence intervals and test for mediation. Results: Mathematical ability (a) was related to PASAT (β=.61; p<.001) and (b) fully mediated the relationship between Intelligence and PASAT (β=.76; 95% confidence interval (CI95)=.28, 1.45; direct effect of Intelligence, β=.42; CI95=−.39, 1.23) as well as the relationship between Education and PASAT (β=2.43, CI95=.81, 5.16, direct effect of Education, β=.83, CI95=−1.95, 3.61). Discussion: Mathematical ability represents a source of error in the clinical interpretation of cognitive decline using the PASAT. Domain-specific cognitive reserve is discussed. (JINS, 2016, 22, 375–378)