Interaction of attention and acoustic factors in dichotic listening for fused words.

Two dichotic listening experiments examined the degree to which the right-ear advantage (REA) for linguistic stimuli is altered by a "top-down" variable (i.e., directed attention) in conjunction with selected "bottom-up" (acoustic) variables. Halwes fused dichotic words were administered to 99 right-handed adults with instructions to attend to the left or right ear, or to divide attention equally. Stimuli in Experiment 1 were presented without noise or mixed with noise that was high-pass or low-pass filtered, or unfiltered. The stimuli themselves in Experiment 2 were high-pass or low-pass filtered, or unfiltered. The initial consonants of each dichotic pair were categorized according to voice onset time (VOT) and place of articulation (PoA). White noise extinguished both the REA and selective attention, and filtered noise nullified selective attention without extinguishing the REA. Frequency filtering of the words themselves did not alter performance. VOT effects were inconsistent across experiments but PoA analyses indicated that paired velar consonants (/k/ and /g/) yield a left-ear advantage and paradoxical selective-attention results. The findings show that ear asymmetry and the effectiveness of directed attention can be altered by bottom-up variables.

Risks and benefits of epilepsy surgery in a pediatric population: Consequences for memory and academic skills.

We examined benefits and risks for memory and academic functioning associated with epilepsy surgery in a pediatric population. A total of 46 patients with intractable seizures and a single seizure focus were divided into four groups according to focus localization: right temporal, left temporal, frontal, and parietal/occipital region. Pre- and postsurgery performance measures were compared across groups and with a fifth group of patients that had intractable seizures but did not undergo surgery. Both groups with temporal lobe epilepsy showed significant declines in memory test scores, while performance of the group with frontal lobe epilepsy improved. These changes were mirrored in parental reports of everyday memory. Consistent with other pediatric studies, no lateralized material-specific declines in the groups with temporal lobe epilepsy were found. When memory improved, the improvement was associated with decreases in seizure frequency and the number of anticonvulsant medications. Presurgical performance was the best predictor of declines in memory test performance. Deterioration of academic test scores in the group that did not have surgery exemplified a potential risk of living with seizures and antiepilepsy medication.

Initial Development of a Modified Trail Making Test for Individuals with Impaired Manual Functioning.

The Trail Making Test (TMT), a widely used neuropsychological test, is highly effective in detecting brain damage. A shortcoming of the test is that it requires drawing lines and thus is impractical for use with persons suffering manual impairment. The 3 studies described herein were designed to describe and evaluate a nonmanual Trail Making Test (NMTMT) that would be suitable for use with manually impaired individuals. The NMTMT utilizes color to permit oral reporting of the stimuli constituting a series of numbers (Part A) or alternating series of numbers and letters (Part B). The studies, which involved a total of 200 university students, indicate that the standard TMT and the NMTMT are moderately related to each other and have similar patterns of association and nonassociation with other neuropsychological measures. Participants with scores falling near the bottom of the NMTMT distribution have a high probability of scoring at least 1 standard deviation below the mean of the TMT distribution for Part B. The clinically important relationship of Part A to Part B seems to be retained in the NMTMT. It is concluded that the NMTMT shows promise as a substitute for the TMT when the TMT cannot be used.

THE SEX DIFFERENCE IN ROD BALANCING: CONFIRMATION OF THE DIFFERENCE AND A TEST OF THREE HYPOTHETICAL EXPLANATIONS.

Previous studies have shown that men can balance a dowel rod on the index finger for a longer time than women can. The factors that account for the difference are unknown, but the difference may be attributable either to a difference in whole-body agility or a difference in the use of visual cues. Three experiments involving a total of 62 adult women with a mean age of 21.2 yr. (SD=3.8) and 62 adult men with a mean age of 21.9 yr. (SD=6.6) tested these potential explanations. Experiment 1 replicated the sex difference and assessed the relevance of whole-body agility by comparing standing and seated conditions. Experiments 2 and 3 explored the role of rod length and visual fixation point, respectively. Each experiment yielded a significant sex difference, but the difference was not affected by the participant's posture, the length of the rod, or the fixation point. Possible alternative explanations for the difference include differences in (1) the speed of processing degree of visual tilt; (2) arm mass, which affects the inertia of the balancing system; and (3) experience in open-skill sports.

The Flynn effect: a meta-analysis.

The Flynn effect refers to the observed rise in IQ scores over time, which results in norms obsolescence. Although the Flynn effect is widely accepted, most efforts to estimate it have relied upon "scorecard" approaches that make estimates of its magnitude and error of measurement controversial and prevent determination of factors that moderate the Flynn effect across different IQ tests. We conducted a meta-analysis to determine the magnitude of the Flynn effect with a higher degree of precision, to determine the error of measurement, and to assess the impact of several moderator variables on the mean effect size. Across 285 studies (N = 14,031) since 1951 with administrations of 2 intelligence tests with different normative bases, the meta-analytic mean was 2.31, 95% CI [1.99, 2.64], standard score points per decade. The mean effect size for 53 comparisons (N = 3,951, excluding 3 atypical studies that inflate the estimates) involving modern (since 1972) Stanford-Binet and Wechsler IQ tests (2.93, 95% CI [2.3, 3.5], IQ points per decade) was comparable to previous estimates of about 3 points per decade but was not consistent with the hypothesis that the Flynn effect is diminishing. For modern tests, study sample (larger increases for validation research samples vs. test standardization samples) and order of administration explained unique variance in the Flynn effect, but age and ability level were not significant moderators. These results supported previous estimates of the Flynn effect and its robustness across different age groups, measures, samples, and levels of performance.

Age-related change in Wechsler IQ norms after adjustment for the Flynn effect: estimates from three computational models.

A previous study found that the Flynn effect accounts for 85% of the normative difference between 20- and 70-year-olds on subtests of the Wechsler intelligence tests. Adjusting scores for the Flynn effect substantially reduces normative age-group differences, but the appropriate amount of adjustment is uncertain. The present study replicates previous findings and employs two other methods of adjusting for the Flynn effect. Averaged across models, results indicate that the Flynn effect accounts for 76% of normative age-group differences on Wechsler IQ subtests. Flynn-effect adjustment reduces the normative age-related decline in IQ from 4.3 to 1.1 IQ points per decade.

Serial recall of visuospatial and verbal information with and without material-specific interference: implications for contemporary models of working memory.

A longstanding question in working memory (WM) research concerns the fractionation of verbal and nonverbal processing. Although some contemporary models include both domain-specific and general-purpose mechanisms, the necessity to postulate differential processing of verbal and nonverbal material remains unclear. In the present two-experiment series we revisit the order reconstruction paradigm that Jones, Farrand, Stuart, and Morris (1995) used to support a unitary model of WM. Goals were to assess (1) whether serial position curves for dot positions differ from curves for letter names; and (2) whether selective interference can be demonstrated. Although we replicated Jones et al.'s finding of similar serial position curves for the two tasks, this similarity could reflect the demands of the order reconstruction paradigm rather than undifferentiated processing of verbal and nonverbal stimuli. Both generalised and material-specific interference was found, which can be attributed to competition between primary and secondary tasks for attentional resources. As performance levels for the combined primary and secondary tasks exceed active WM capacity limits, primary task items apparently are removed from active memory during processing of the secondary list and held temporarily in maintenance storage. We conclude that active WM is multimodal but maintenance stores may be domain specific.

Behavioral and academic problems in children with Sturge-Weber syndrome: differences between children with and without seizures.

Although Sturge-Weber (SWS) syndrome is associated with behavioral and academic problems in childhood, it is unknown whether those problems are concomitants of the disorder itself or of the seizure disorder that is common in SWS. We compared two groups of children with SWS-- one with seizures (n=20) and one without seizures (n=14)--on parent-report and teacher-report measures of behavioral and academic functioning. The two subgroups were compared with each other as well as with children with epilepsy alone (n=29) and a group of healthy controls (n=21). The SWS group with seizures was more impaired than the seizure-free group on 9 of 15 measures and the children with seizures were 10 times as likely to have received special education services. Overall, children with SWS and seizures were similar to the epilepsy group, whereas children with SWS and no seizures were similar to the controls.

Auditory evoked potentials of adults who do or do not show a significant right ear advantage in dichotic listening.

The Halwes Fused Dichotic Words Test was used to divide a sample of university students into a group having a statistically significant right ear advantage (REA) and a group having either a significant left ear advantage or a non-significant ear asymmetry (NREA). Of these participants, 30 (14 REA, 16 NREA) had electrical potentials measured from temporal, central, and frontal sites as series of brief tones were presented monaurally. No behavioural response was required. Group differences were found in the latency but not the amplitude of the averaged event-related responses. The REA group showed faster conduction to the right hemisphere than to the left hemisphere. In both groups the amplitude of left hemisphere responses was greater for right ear stimulation than for left ear stimulation. The results for amplitude indicate that the crossed auditory pathway is a superior conductor of information to the left hemisphere but not to the right hemisphere. Group differences, however, are related only to the speed with which information reaches the right hemisphere.

The Flynn effect in neuropsychological assessment.

The Flynn effect refers to the rise in IQ throughout the 20th century. This study examined whether the Flynn effect has also elevated performance on neuropsychological tests. A search of published norms revealed five tests with appropriate normative data available for comparison. These tests were the Trail-Making Test (TMT), Symbol Digit Modalities Test (SDMT), Boston Naming Test, Finger Tapping, and Grooved Pegboard. Results indicated a strong Flynn effect for Parts A and B of the TMT and a probable Flynn effect for the oral SDMT. No Flynn effect was evident for the other tests. Implications for clinical assessment are discussed.

Everyday verbal memory and pediatric epilepsy.

This study addressed the reliability and validity of reports of everyday verbal memory with a sample of 132 pediatric patients with epilepsy. Each patient and one parent completed a questionnaire on everyday verbal memory comprising two scales assessing learning/retrieval and prospective memory. Each patient was also administered tests of memory, attention, and academic skills. Information about attention, mood, and academic performance was obtained from parent and teacher report, as well as self-report. Memory test scores were correlated with children's reports of learning and retrieval in everyday activities, but were not significantly associated with reports of prospective memory. Reports of everyday memory were found to be reliable and predictive of academic performance. Performance on tests of memory, conversely, was unrelated to reports of academic performance. Reports of everyday memory may, therefore, provide more useful information than tests when evaluating the effects of epilepsy and its treatments.

Attention and the right-ear advantage: what is the connection?

Dichotic listening originally was a means of studying attention. Half a century ago Doreen Kimura parlayed the dichotic method into a noninvasive indicator of lateralized cerebral language representation. The ubiquitous right-ear advantage (REA) for verbal material was accepted as a concomitant of left-sided language lateralization and preferential conduction of right-ear messages to the left hemisphere. As evidence has accumulated over the past 50years showing the REA to be dynamic and modifiable, the concept of attention has become essential for interpreting the findings. Progress in understanding the role of attention has been manifested as a transition from efforts to document attention effects to efforts to characterize their mechanisms. We summarize the relevant evidence, trace the evolution of explanatory models, and outline contemporary accounts of the role of attention in dichotic listening.

Age-related IQ decline is reduced markedly after adjustment for the Flynn effect.

Twenty-year-olds outperform 70-year-olds by as much as 2.3 standard deviations (35 IQ points) on subtests of the Wechsler Adult Intelligence Scale (WAIS). We show that most of the difference can be attributed to an intergenerational rise in IQ known as the Flynn effect. Normative data from different versions of the WAIS enabled us to estimate the degree to which the Flynn effect, rather than age-related decline, contributes to differences between 20- and 70-year-olds. The Flynn effect accounted for 38-67% of the apparent age-related decline on 6 of the 11 subtests. On the other 5 subtests, all of which are categorized as verbal, the Flynn effect was larger than the age-group difference. For these verbal subtests, the Flynn effect masked a modest increase in ability as individuals grow older. Overall, the Flynn effect accounted for at least 85% of the disparity between 20- and 70-year-olds.

Cognitive effects of pegylated interferon in individuals with primary brain tumors.

Cognitive changes associated with interferon treatment include impaired verbal memory, attention, processing speed, and executive functioning. Pegylated interferon is a relatively new, long-lasting form of interferon alpha, but data regarding its cognitive effects in brain tumor patients are limited. Participants in this study were 35 primary brain tumor patients who received pegylated interferon at tumor recurrence. A neuropsychological battery assessed verbal memory, executive functioning, attention, information processing speed, and language functioning. Individual growth curve analyses were used to estimate cognitive change throughout treatment with interferon. Results revealed performance declined on a task of psychomotor speed and upper extremity dexterity. Although decline in a few tests was found, its degree may have been reduced because individuals were tested after tumor recurrence where a substantial amount of cognitive change had already potentially occurred due to surgery, radiation therapy, and chemotherapy. Thus, participants may not have been starting at their baseline cognitive status and the potential neurotoxic effects of interferon may have been obscured by prior treatments. An alternative explanation, however, is that treatment with pegylated interferon did not produce further impairment and patients experienced stability in their cognitive functioning.

Arithmetic performance in children with Tourette syndrome: relative contribution of cognitive and attentional factors.

The study addressed the issue of arithmetic deficiencies in children with Tourette syndrome (TS) as well as explanations for such deficiencies. A total of 47 children with TS were assigned to three subgroups based on a composite attention score from the Test of Variables of Attention (TOVA). These children, along with 17 normal controls between 8 and 16 years of age, were tested on standardized measures of IQ, attention, visuospatial ability, and arithmetic achievement. The children also were administered an experimental calculation task with two levels of structure. Children with TS scored below controls on tests of IQ, attention, and arithmetic achievement but not visuospatial ability. The TS subgroup with the greatest impairment of attention accounted for most of the differences in arithmetic achievement. Regression analysis, based on the 47 children with TS, indicated that IQ and TOVA scores were the best predictors of arithmetic achievement. Likewise, the experimental calculation task indicated that the poor performance of some children with TS could be attributed to deficient attention. Irrespective of structure, children in the TS subgroup with the greatest attentional impairment made more attention (but not visuospatial) errors than did controls on the experimental task. Thus, on both the standardized and the experimental tasks, poor arithmetic skill was found only in children with TS who had significant attentional deficits.

The Flynn effect and its relevance to neuropsychology.

Evidence from several nations indicates that performance on mental ability tests is rising from one generation to the next, and that this "Flynn effect" has been operative for more than a century. No satisfactory explanation has been found. Nevertheless, the phenomenon has important implications for clinical utilization of IQ tests. This article summarizes the empirical basis of the Flynn effect, arguments about the nature of the skill that is increasing, and proposed explanations for the cause of the increase. Ramifications for clinical neuropsychology are discussed, and some of the broader implications for psychology and society are noted.

Neuropsychological function in adults with von Recklinghausen's neurofibromatosis.

The cognitive function of adults with von Recklinghausen's neurofibromatosis (NF-1) was examined. This study sought to replicate in an adult sample the findings of decreased visuospatial and attention abilities reported for many children with NF-1. Specifically, it was anticipated that adults with NF-1 would be classified separately from unaffected controls according to visual and attention-executive function skills. Second, this study examined whether language skills discriminated between adults with NF-1 and unaffected controls. The sample included 20 participants with NF-1 and 25 control participants. All participants were administered a battery of neuropsychological tests (Developmental Test of Visual-Motor Integration (VMI), Judgment of Line Orientation (JLO), Visual Form Discrimination, Booklet Category Test, Figure Cancellation, Peabody Picture Vocabulary Test-Revised (PPVT-R), Sentence Repetition, Controlled Oral Word Association). The results of a discriminant function analysis partially supported the hypothesis: Two of the tests of visual-spatial skill (VMI, JLO) and one of the language tests (PPVT-R) were found to be the best predictors for group membership. The discriminant function accounted for 45% of the variance between the groups and correctly classified 15 of the NF-1 participants and 21 of the control participants. Post hoc exploratory analyses revealed that the VMI was the most important test in discriminating between the groups. It is suggested that patients with NF-1 will tend to have sparing of basic cognitive functions but will have greater impairment on tests that use multiple cognitive skills.

Concurrent counting and typing: lateralized interference depends on a difference between the hands in motor skill.

In previous demonstrations of differences between left- and right-handers in dual-task performance, participants' hand preference has been confounded with asymmetry of manual skill. The present study was designed to disentangle those two factors as sources of lateralized interference in the concurrent-task paradigm. Forty-eight normal adults (24 females and 24 males) counted backward by ones or by twos while typing an easy or difficult sequence of letters with either hand. When participants were grouped according to self-reported hand preference, both groups showed bilaterally symmetric slowing, relative to single-task conditions. However, when the same participants were grouped according to manual asymmetry in the baseline condition, the cognitive task interfered significantly more with the faster hand than with the slower hand. Baseline typing rate, averaged across hands, did not influence dual-task interference. Both self-reported left-hand preference and left-hand superiority in baseline typing were associated with reduced interference on the cognitive task, and the reduced interference in those groups seemed to reflect relatively loose coupling between manual and cognitive tasks. The results support and extend Caroselli et al.'s (1997) findings regarding the effect of baseline manual asymmetry on the pattern of dual-task interference. Irrespective of the participant's hand preference, the presence or absence of baseline asymmetry may be sufficient to determine whether dual-task interference is lateralized.

Dual-task interference in right- and left-handers: typical laterality patterns are obtained despite reversal of baseline asymmetries.

Lateralized interference between concurrent cognitive and manual activities is used to infer cerebral hemisphere specialization for the cognitive activity. However, some evidence indicates that lateralized interference depends largely on manual asymmetry in the single-task (baseline) condition. To test the competing explanations, we asked 40 right-handed (RH) and 40 left-handed (LH) adults to key press and calculate concurrently. Baseline manual asymmetries were manipulated by increasing the complexity of the task performed by the dominant hand. Nevertheless, in the dual-task conditions, RHs showed more overall interference when performing with the right hand and LHs showed a nonsignificant tendency in the opposite direction. The results indicate that differential interference patterns, similar to those previously reported for right- and left-handers, may be obtained even when the usual baseline manual asymmetries are reversed.

The simulated gambling paradigm applied to young adults: an examination of university students' performance.

Simulated gambling tasks have become popular as sensitive tools for identifying individuals with real-time impairment in decision making. Various clinical samples, especially patients with damage to the ventromedial prefrontal cortex, perform poorly on these tasks. The patients typically persist in choosing risky (disadvantageous) card decks instead of switching to safer (advantageous) decks. In terms of Damasio's (1994) somatic marker hypothesis, the poor performance stems from defective integration of emotional and rational aspects of decision making. Less information is available about performance in healthy populations, particularly young adults. After administering a computerized gambling task to 141 university students, we found that individuals in this population also tend to prefer disadvantageous decks to advantageous decks. The results indicate that performance is governed primarily by the frequency of positive outcomes on a trial-by-trial basis rather than by the accumulation of winnings in the longer term. These findings are discussed in light of the cognitive literature pertaining to the simulated gambling paradigm.