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We studied the role of sensorimotor and working memory systems in supporting development of perceptual rhythm processing with 119 participants aged 7–12 years. Children were assessed for their abilities in sensorimotor synchronization (SMS; beat tapping), auditory working memory (AWM; digit span), and rhythm discrimination (RD; same/different judgment on a pair of musical rhythm sequences). Multiple regression analysis revealed that children's RD performance was independently predicted by higher beat tapping consistency and greater digit span score, with all other demographic variables (age, sex, socioeconomic status, music training) controlled. The association between RD and SMS was more robust in the slower tempos (60 and 100 beats‐per‐minute (BPM)) than faster ones (120 and 180 BPM). Critically, the relation of SMS to RD was moderated by age in that RD performance was predicted by beat tapping consistency in younger children (age: 7–9 years), but not in older children (age: 10–12 years). AWM was the only predictor of RD in older children. Together, the current findings demonstrate that the sensorimotor and working memory systems jointly support RD processing during middle‐to‐late childhood and that the degree of association between the two systems and perceptual rhythm processing is shifted before entering into early adolescence. [ABSTRACT FROM AUTHOR]

The informative value of time and temporal structure often remains neglected in cognitive assessments. However, next to information about stimulus identity we can exploit temporal ordering principles, such as regularity, periodicity, or grouping to generate predictions about the timing of future events. Such predictions may improve cognitive performance by optimising adaptation to dynamic stimuli. Here, we investigated the influence of temporal structure on verbal working memory by assessing immediate recall performance for aurally presented digit sequences (forward digit span) as a function of standard (1000 ms stimulus‐onset‐asynchronies, SOAs), short (700 ms), long (1300 ms) and mixed (700–1300 ms) stimulus timing during the presentation phase. Participant's digit spans were lower for short and mixed SOA presentation relative to standard SOAs. This confirms an impact of temporal structure on the classic "magical number seven," suggesting that working memory performance can in part be regulated through the systematic application of temporal ordering principles. [ABSTRACT FROM AUTHOR]

The framework of plateaus, dips, and leaps shines light on periods when individuals may be inventing new methods of skilled performance. We begin with a review of the role performance plateaus have played in (a) experimental psychology, (b) human-computer interaction, and (c) cognitive science. We then reanalyze two classic studies of individual performance to show plateaus and dips which resulted in performance leaps. For a third study, we show how the statistical methods of Changepoint Analysis plus a few simple heuristics may direct our focus to periods of performance change for individuals. For the researcher, dips become the marker of exploration where performance suffers as new methods are invented and tested. Leaps mark the implementation of a successful new method and an incremental jump above the path plotted by smooth and steady log-log performance increments. The methods developed during these dips and leaps are the key to surpassing one's teachers and acquiring extreme expertise. [ABSTRACT FROM AUTHOR]

Background: A detrimental effect of commonly used anesthetics on the neurodevelopmental and behavioral parameters has long been shown in young animals subjected to early childhood anesthesia. Epidemiologic studies suggest the possibility of a modestly elevated risk of adverse neurodevelopmental outcomes in children exposed to anesthesia during early childhood. However, these results are still preliminary and inconclusive. Aim: To further elucidate the probability of occurrence of such adverse outcomes, we evaluated cognitive performance of children who underwent general anesthesia early in their childhood. Method: One hundred and fifteen children aged 5-16 years with established glaucoma were included in the study. Of these, 68 children had a history of at least one general anesthesia with sevoflurane before age 3. Phonemic and semantic verbal fluency, and forward and backward digit span tests were performed to evaluate cognitive function in the study subjects. Results: The two-way ANOVA revealed that all these variables showed significant changes in various age groups, but they were comparable among subjects with no, single, or multiple childhood anesthesia. Conclusion: It can be concluded that brief periods of anesthesia with single anesthetic sevoflurane may be safe for children under age 3. [ABSTRACT FROM AUTHOR]

ABSTRACT Fluctuations in mental status are 1 of the core diagnostic criteria for dementia with Lewy bodies (DLB) and are thought to reflect variability in daytime alertness. Previous attempts to study fluctuations have been limited to caregiver reports, observer rating scales, short segments of electroencephalography, or motor-dependent, reaction time tests. Concordance among such measures is often poor, and fluctuations remain difficult to quantify. We compared fluctuations in cognition and alertness in patients with DLB (n = 13) and idiopathic Parkinson's disease (PD) (n = 64), a condition associated with deficits in daytime alertness. We systematically and repeatedly collected cognitive and physiologic measures during a 48-hour inpatient protocol in a sound-attenuated sleep laboratory in a geriatric hospital. Cognitive fluctuations were analyzed using coefficients of variation (COVs) derived from performance on a bedside examination familiar to clinicians (digit span). Alertness fluctuations were assessed objectively using COVs from the polysomnographically-based Maintenance of Wakefulness Test. Despite predictably lower mean digit span performances, DLB patients demonstrated significantly greater cognitive fluctuations than PD patients ( P < 0.001), even when groups were matched on general cognitive impairment. There were no group differences in alertness fluctuations, although DLB patients were less alert than PD patients not receiving dopaminergics. The prevailing assumption that fluctuations in cognition in DLB are reflected in fluctuations in daytime alertness was not supported by objective, physiological measurements. Fluctuating mental status in DLB patients can be detected with repeated administration of a simple bedside exam that can be adapted to a clinic setting. © 2013 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Working memory performance has been inconsistently reported in autism spectrum disorders (ASD). Several studies in ASD have found normal performance in digit span and poor performance in digit symbol task although these are closely related with working memory. It is assumed that poor performance in digit symbol could be explained by confirmatory behavior, which is induced due to the vague memory representation of number–symbol association. Therefore it was hypothesized that the performance of working memory task, in which vagueness did not cause confirmatory behavior, would be normal in ASD. For this purpose, the Advanced Trail Making Test (ATMT) was used. The performance of digit span, digit symbol and ATMT was compared between ASD and normal control. The digit span, digit symbol and ATMT was given to 16 ASD subjects and 28 IQ-, age- and sex-matched control subjects. The scores of these tasks were compared. A significantly lower score for ASD was found only in digit symbol compared with control subjects. There were no significant difference in digit span and working memory estimated by ATMT. Discrepancy of scores among working memory-related tasks was demonstrated in ASD. Poor digit symbol performance, normal digit span and normal working memory in ATMT implied that ASD subjects would be intact in working memory itself, and that superficial working memory dysfunction might be observed due to confirmatory behavior in digit symbol. Therefore, to evaluate working memory in ASD, tasks that could stimulate psychopathology specific to ASD should be avoided. [ABSTRACT FROM AUTHOR]

Background: Although bipolar disorder and schizophrenia have long been viewed as distinct illnesses, there is growing evidence that these two complex diseases share some common genes, which may manifest as overlapping neuropsychological impairments. Although working memory dysfunction has been proposed to be central to the pathophysiology of schizophrenia, it has received less attention in studies of bipolar disorder. Method: We applied measures of working memory to patients with schizophrenia (n = 15), patients with schizoaffective disorder (n = 15), patients with psychotic (n = 11) and non-psychotic (n = 15) bipolar disorder, and demographically matched healthy subjects (n = 32), in order to determine the extent to which these groups show common or unique impairments. Results: While patients with bipolar disorder (with and without psychotic features) and those with schizophrenia/schizoaffective disorder were impaired on backward digit span, only patients with a lifetime history of psychotic features, regardless of diagnosis, were impaired on spatial delayed response task. Conclusions: Backward digit span performance is comparable in bipolar disorder and schizophrenia, and may be an appropriate endophenotypic marker that cuts across diagnostic categories. In contrast, spatial working memory performance clearly distinguishes non-psychotic bipolar disorder patients from patients with functional psychosis. [ABSTRACT FROM AUTHOR]

The lateral prefrontal cortex is critical for the control and organization of information in working memory. In certain situations, effective reorganization can attenuate task difficulty, suggesting a dissociation between lateral prefrontal activity and basic memory demand. In a verbal working memory task, we investigated the enhancement of performance that occurs when incoming information can be reorganized into higher-level groups or chunks. In the fMRI scanner, volunteers heard and repeated a sequence of digits. Mathematically structured sequences, encouraging ‘chunking’, were compared with unstructured, random sequences. Though structured sequences were easier to remember, fMRI showed increased lateral prefrontal activation for these sequences. Specifically, both the dorsolateral and ventrolateral prefrontal cortices were activated preferentially for the structured sequences during encoding. When visual stimuli that can be chunked using spatial structure are used, similar results are observed. These results demonstrate that cognitively less demanding tasks may elicit greater lateral prefrontal recruitment. Thus, the lateral prefrontal cortex appears to play a general role in strategically recoding information from memory, in order to optimize performance. [ABSTRACT FROM AUTHOR]

The effects of practice on a range of performance measures often used in studies of psychoactive drugs have been assessed in 50 normal healthy adult volunteers, during 10 practice sessions over an 8-day period. There was no dramatic effect of practice on any of the parameters measured, only one of the mean values at the tenth session exceeded one standard deviation of the mean of the first session (manipulative motor task). Practice did not materially affect performance on elapsing time estimation, tapping rate, body sway measured by a ultrasonic method or rapid visual information processing task variables. There tended to be a non-significant, exponential learning curve for choice reaction response and movement times to visual stimuli, flash fusion threshold and the manipulative motor task, with a statistically significant practice effect on all 16 visual analogue scales used; a plateau was apparently achieved by the fifth practice session for all these parameters. There was a statistically significant straight-line improvement in digit span across the 10 sessions. It is concluded that for most simple measures of performance used in psychopharmacology including visual analogue scales, four pre-study training sessions are necessary, and that direct methods of recording body sway are preferred to indirect methods such as the balance platform. [ABSTRACT FROM AUTHOR]

P300 latency from a simple auditory discrimination counting task was obtained along with a digit span memory task for a large group of neurologically normal subjects. Moderate significant negative correlations between the peak latency of the P3a and P3b subcomponents and total memory score were found, although no relationship was observed for other waveform component latencies and memory score. The data suggest that the P300 component of the event-related brain potential may index individual variations in memory ability. [ABSTRACT FROM AUTHOR]

This study investigated changes in frequency of the EEG in relation to the number of digits inputed in a test of short-term memory. Four channels of bipolar EEGs were recorded from scalp leads over parietal and occipital areas of both hemispheres, while lists of the WISC digit span backward test were inputed. Data from 25 healthy Ss, who correctly recalled the 2-, 3-, 4-, and 5-digit lists in reversed order, were analyzed. Findings showed no statistically significant differences in frequency of the EEGs recorded during acquisition of lists of different length. EEG frequency was significantly faster during acquisition of the lists than during a control condition in which Ss participated in an auditory reaction time task; but the findings were not consistent from channel to channel. [ABSTRACT FROM AUTHOR]

The relationship between P300 latency and digit span reported by Polich, Howard, and Starr (1983) is re-examined. Evidence is presented which shows that these authors' use of partial correlation to correct for age differences in their sample of subjects is erroneous because the assumption of linear regression is clearly not satisfied. This finding seriously questions Polich et al.'s conclusion that P300 latency and digit span covary irrespective of any relationship of the variables to age. [ABSTRACT FROM AUTHOR]