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Evidence suggests falls and postural instabilities among seniors are attributed to a decline in both the processing of afferent signals (e.g., proprioceptive, vestibular) and attentional resources. We investigated the interaction between the non-visual and attentional demands of postural control in sedentary seniors. Old and young adults performed a postural stability limit task involving a maximal voluntary leaning movement with and without vision as well as a cognitive-attentional subtraction task. These tasks were performed alone (single-task) or simultaneously (dual-task) to vary the sensory-attentional demands. The functional limits of stability were quantified as the maximum center of pressure excursion during voluntary leaning. Seniors showed significantly smaller limits of postural stability compared to young adults in all sensory-attentional conditions. However, surprisingly, both groups of subjects reduced their stability limits by a similar amount when vision was removed. Furthermore, they similarly decreased their anterior-posterior stability limits when concurrently performing the postural and the cognitive-attentional tasks with vision. The overall average cognitive performance of young adults was higher than seniors and was only slightly affected during dual-tasking. In contrast, older adults markedly degraded their cognitive performance from the single- to the dual-task situations, especially when vision was unavailable. Thus, their dual-task costs were higher than those of young adults and increased in the eyes-closed condition, when postural control relied more heavily on non-visual sensory signals. Our findings provide the first evidence that as posture approaches its stability limits, sedentary seniors allot increasingly large cognitive attentional resources to process critical sensory inputs. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the association between event-related potential (ERP) P300 with cognitive function in people with diabetic peripheral neuropathy (DPN). Methods: We performed a cross-sectional analysis of 19 type 2 diabetes mellitus (T2DM) patients, aged 18 and older with DPN. The participants were assessed for neuropathy, cognitive function, & dual-task performance. DPN was examined via the administration of diabetic neuropathy symptom score (DNSS) and vibration perception threshold (VPT). Cognitive dysfunction was evaluated using Mini-mental state examination (MMSE), trail making test-B (TMT-B), and ERP P300 wave latency & amplitude. For assessing dual-task performance, the dual-task cost (DTC) was calculated using the timed-up and go (TUG) test and TUG with dual task (TUG-DT). Results: P300 latency was linearly related to TMT-B (R = 0.31, p = 0.01) and DTC (R = 0.22, p = 0.04). A similar trend was observed in TMT-B (R = 0.13, p = 0.04) & DTC (R =0.67, p = 0.001) with respect to P300 amplitude. MMSE did not relate with P300 latency (R = 0.14, p = 0.58) & amplitude (R = 0.63, p =.44). Conclusion: P300 latency and amplitude are associated with cognitive function and DTC of individuals with DPN. [ABSTRACT FROM AUTHOR]

When simultaneously performing two tasks that share response properties, interference can occur. Besides general performance decrements, performance in the first task is worse when the second task requires a spatially incompatible response, known as the backward crosstalk effect (BCE). The size of this BCE, similar to congruency effects in conflict tasks, is subject to a sequential modulation, with a smaller BCE after incompatible compared to compatible trials. In the present study, we focus on a potential bidirectional interaction between crosstalk (and its resolution) at a lower level of task performance and higher-order processes of task organization. Two questions were of particular interest: First, do participants switch task order more frequently after a conflict-prone incompatible trial than after a compatible trial? Second, does changing task order influence the efficiency of conflict resolution, as indexed by the size of the sequential modulation of the BCE. Across four experiments, we only found marginal evidence for an influence of lower-level conflict on higher-order processes of task organization, with only one experiment revealing a tendency to repeat task order following conflict. Our results thus suggest practical independence between conflict and task-order control. When separating processes of task selection and task performance, the sequential modulation was generally diminished, suggesting that conflict resolution in dual-tasks can be disrupted by a deliberate decision about task order, or, alternatively, by a longer inter-trial interval. Finally, the study found a strong bias towards repeating the same task order across trials, suggesting that task-order sets not only impact task performance but also guide task selection. [ABSTRACT FROM AUTHOR]

Some studies have suggested that postural balance improved after a single session of transcranial direct current stimulation (tDCS), whereas others have found minimal, if any, effects on postural performance. To address the issue of replication in tDCS studies, we re-tested the anodal tDCS effects of left dorsolateral prefrontal cortex while performing a dual-task by increasing the attentional demands associated with more challenging proprioceptive conditions. Twenty-four young adults (mean age: 21.3 ± 1.2 years) were randomly divided into two groups (a "real tDCS" vs. a "sham tDCS" group) were asked to maintain a quiet stance on a force platform. Eight trials were conducted, with eyes open and eyes closed, standing on a firm and foam surface and performing a simple and dual-task (backward counting). The postural performance was assessed by various centre-of-pressure parameters before and immediately after a 20-min tDCS session. No main effect of group and no interaction considering this factor were observed, regardless of the centre-of-pressure variables (all p values > 0.1). No evidence of a more efficient postural control emerged after a tDCS session. Beyond promising research on tDCS to maximize cognitive and behavioural enhancement, the current results indicate that caution needs to be taken when drawing firm conclusions, at least in young healthy adults. [ABSTRACT FROM AUTHOR]

Humans integrate visual information about their surrounding environment to properly adapt their locomotion to step over or around obstacles in their path. We know that cognition aids in the execution of locomotion and in complex maneuvers such as obstacle avoidance. However, the role of the cognitive system in performing online adjustments to an obstacle avoidance strategy during locomotion has not yet been elucidated. Nineteen young adults instrumented with kinematic markers were asked to step over or circumvent an obstacle to the left or right. In half of these trials, participants were required to adjust this strategy when cued by LED lights two steps prior to obstacle crossing. In 75% of trials, a cognitive task was simultaneously presented (incongruent or congruent auditory Stroop cue, or neutral cue). Center of mass position and velocity was estimated and gait metrics (eg. step length) were calculated to quantify how individuals performed this last-minute direction change and determine how these responses changed when simultaneously performing a cognitive task. Results showed statistically shorter crossing steps, where the trailing limb was placed further from the leading edge and the lead limb was placed closer to the trailing edge when responding to the auditory Stroop task. Performing these avoidance strategy changes also decreased cognitive task performance. Our findings suggest that visually integrating a new stepping pattern to cross an obstacle is a complex locomotor maneuver, and requires the aid of the cognitive system to be performed effectively in a young adult population. [ABSTRACT FROM AUTHOR]

Background: The ability to maintain adequate motor-cognitive performance under increasing task demands depends on the regulation and coordination of neural resources. Studies have shown that such resources diminish with aging and disease. EEG spectral analysis is a method that has the potential to provide insight into neural alterations affecting motor-cognitive performance. The aim of this study was to assess changes in spectral analysis during dual-task walking in aging and disease Methods: 10 young adults, ten older adults, and ten patients with Parkinson's disease (PD) completed an auditory oddball task while standing and while walking on a treadmill. Spectral power within four frequency bandwidths, delta (< 4 Hz), theta (4–8 Hz), alpha (8–12 Hz), and beta (12–30 Hz), was calculated using Event-Related Spectral Perturbation (ERSP) analyses and compared between single task and dual task and between groups. Results: Differences in ERSP were found in all groups between the single and dual-task conditions. In response to dual-task walking, beta increased in all groups (p < 0.026), delta decreased in young adults (p = 0.03) and patients with PD (0.015) while theta increased in young adults (p = 0.028) but decreased in older adults (p = 0.02) and patients with PD (p = 0.015). Differences were seen between the young, the older adults, and the patients with PD. Conclusions: These findings are the first to show changes in the power of different frequency bands during dual-task walking with aging and disease. These specific brain modulations may reflect deficits in readiness and allocation of attention that may be responsible for the deficits in dual-task performance. [ABSTRACT FROM AUTHOR]

Gait stability and secondary task performance are affected by the need to share attention when dual-tasking. Further decrements may result from the need to switch attention between multiple secondary tasks. The aim of the current study was to determine the effects of attention switching upon gait stability and task performance in healthy younger and older adults. Ten healthy younger and ten healthy older adults walked on a treadmill at their preferred speed during three trials including: (1) baseline walking; (2) non-switching task walking, requiring response to an auditory-spatial or visual-spatial cue presented in an expected order; and (3) switching task walking, which required response to an auditory-spatial or visual-spatial cue presented in an unexpected order. Response time and accuracy, the margin of stability in the frontal (MoSML) and sagittal planes (MoSA: anterior, MoSP: posterior), step width and step length were calculated for non-switching and switching tasks. The MoSML, MoSA, MoSP, step width and step length during non-switching and switching tasks were normalized to baseline walking. Older adults took significantly longer to respond to cues and made more errors during the switching task compared to younger adults. Younger adults took narrower steps (p < 0.01) and displayed a reduction in MoSML (p < 0.01) during the switching task compared with the non-switching task. Conversely, older adults displayed no differences in MoSML between tasks. These findings suggest that attention switching results in different task prioritization strategies in younger and older adults during walking. [ABSTRACT FROM AUTHOR]

In two experiments (N= 60 each), we investigated the locus of backward crosstalk effects in dual tasking. Specifically, we embedded the typical flanker task within a dual-task paradigm by assigning stimulus-response (S-R) rules to the flankers. In Experiment 1, participants were instructed to first respond to the center letter and only respond to the flanker if the center was a no-go stimulus (i.e., prioritized processing paradigm). Mapping condition was varied between-subjects to be either matched (i.e., same S-R rule for flankers as for center letters), reversed (i.e., opposite S-R rule for flankers), or neutral (i.e., different letters for flankers with separate S-R rules). The results indicated that the backward crosstalk effect was mainly driven by a stimulus-based compatibility, as indicated by a significant S2−R1 compatibility effect in the matched and reversed conditions, with little change in this effect between the matched and reversed conditions. Experiment 2 replicated and extended these findings to a psychological refractory period paradigm. The present findings suggest that in the matched and reversed conditions, there was only one S-R rule active at a time. [ABSTRACT FROM AUTHOR]

Previous research has suggested that the calculation of another’s perspective is cognitively efficient, whereas perspective selection (selection of a particular perspective, self or other) is associated with executive function, particularly inhibitory control. However, research has not previously tested how perspective calculation and selection may be associated with another key executive function, working memory. In the present study (N = 54 adult participants), we administered a Level-1 visual perspective task in a dual-task paradigm in which the secondary task required working memory. The results suggest that executive function is associated with both perspective calculation and perspective selection, contrary to previous evidence from similar dual-task studies that had used inhibitory control and attention-based secondary tasks. This contrast may suggest that working memory capacity facilitates perspective-taking. Furthermore, it may follow that the notion of simple perspective-taking is distinct from more the complex and cognitively demanding “theory of mind.” Research of this nature warrants further investigation. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether cognitive processing for defining step precision during walking could induce changes in electrocortical activity. Ten healthy adults (21-36 years) were asked to walk overground in three different conditions: (1) normal walking in a straight path (NW); (2) walking in a pre-defined pathway forcing variation in step width and length by stepping on green marks on the floor (only one color: W1C), and (3) walking in the same pre-defined W1C pathway while evaluating different combinations among the colors green, yellow and red, in which only one color was the footfall target (evaluating two colors: W2C). Walking speed, stride duration and scalp electroencephalography (EEG) were recorded from all conditions. Event-related spectral perturbation was calculated for channels Fz, Cz, C3, C4, Pz and Oz in each condition, which were all time-normalized in relation to the gait cycle. The results showed that walking speed was reduced and stride duration was increased for W2C when compared to both NW and W1C (p < 0.01). Moreover, Event-related spectral perturbation analysis revealed significant changes (p < 0.05) during mid-stance in the frontal lobe and motor/sensorimotor regions, a phase in the gait cycle in which participants define the correct foot placement for the next step. These results suggest that greater cognitive demands during precision stepping influences electrocortical dynamics especially towards step transitions. Therefore, increased electrocortical activity in cognitive, motor and sensorimotor areas may be relevant to produce patterned and safe locomotion through challenging paths. [ABSTRACT FROM AUTHOR]

Background and aims: The purpose was to explore the impact of balance and mobility training (BMT), balance and mobility plus cognitive training (BMT + C) and no training on the timed up and go (TUG), TUG cognitive (TUGcog), and TUG manual (TUGman) in older adults. A preliminary experiment examined the stability of these TUG measures over a 5-week period in older adults. Methods: Fifteen participants in the BMT group (70.2 ± 3.2 years) and 14 participants in the BMT + C group (68.7 ± 5.5 years) trained one-on-one, 3×/week for 12 weeks on a balance obstacle course. The BMT group and the BMT + C group completed two or three tasks simultaneously, respectively. Fifteen participants in the control group received no training (66.7 ± 4.2 years). The TUG, TUGcog, and TUGman were measured in seconds at baseline, after the 12-week training, and after the 12-week follow-up. During the preliminary experiment, ten participants (67.0 ± 6.9 years) completed the three TUG measures 1/week for 5 weeks. Results: Both the BMT and BMT + C groups, but not the control group, exhibited significantly faster TUG, TUGcog, and TUGman after the intervention and maintained these improvements at the 12-week follow-up. No differences between the BMT and BMT + C groups emerged. The preliminary experiment showed that the three TUG measures were stable across five testing sessions. Discussion and conclusion: Both training groups improved functional mobility after the interventions and sustained these improvements over 12 weeks. This is likely not a function of repeating the TUG, TUGcog, and TUGman tests since no repeated exposure effect was shown. [ABSTRACT FROM AUTHOR]

The dual-task (motor and cognitive) performance of eight older adults (72.0 ± 6.4 years; 5 female; 3 male) was evaluated. Vocal choice reaction times (cognitive task) were measured at standstill as well as during unperturbed and perturbed gait (motor task). The perturbation was administered using customized shoes instrumented to lower a small (18.4 mm high) aluminum flap suddenly under the medial or lateral forefoot during a single swing phase of 12 of 30 gait trials. The ankle inverted or everted an average of 10 or 9 degrees, respectively, depending on the flap deployed. Medial and lateral perturbations were randomized between the left and right feet. The results show that vocal choice reaction time was significantly prolonged by gait, both perturbed (614.7 ± 80.2 ms) and unperturbed (529.9 ± 119.3 ms), compared to standstill (332.8 ± 76.5 ms; p = 0.0015). Further, the prolongation associated with gait perturbation was significant, compared to that with unperturbed gait ( p = 0.016). The kinematics of the first post-perturbation (recovery) step, with or without concomitant vocal choice reaction task performance, was not significantly different from those of the average step during unperturbed gait. We conclude that in healthy older adults, the requirement to respond to a gait challenge resulted in deterioration in the performance of a concurrent cognitive task as indicated by significant prolongation of response time in the vocal choice reaction task. In contrast, performance of the motor task was not adversely affected. [ABSTRACT FROM AUTHOR]

The center of pressure (COP) movement in studies of postural control reveals a highly regular structure (low entropy) over short time periods and a highly irregular structure over large time scales (high entropy). Entropic half-life (EnHL) is a novel measure that quantifies the time over which short-term temporal correlations in a time series deteriorate to an uncorrelated, random structure. The current study suggested and tested three hypotheses about how characteristics of the neuromuscular postural control system may affect stabilometric EnHL: (H1) control system activity hypothesis: EnHL decreases with increased frequency of control system interventions adjusting COP motion; (H2) abundance of states hypothesis: EnHL decreases with increased number of mechanically equivalent states available to the postural system; and (H3) neurologic process hierarchy hypothesis: EnHL increases if postural control functions shift from the spinal level to the motor cortex. Thirty healthy participants performed quiet stance tests for 90 s in 18 different conditions: stance (bipedal, one-legged, and tandem); footwear (bare foot, regular sports shoe, and rocker sole shoes); and simultaneous cognitive task (two-back working memory task, no challenge). A four-way repeated-measures ANOVA revealed significant changes in EnHL for the different stance positions and for different movement directions (medio-lateral, anterior-posterior). These changes support H1 and H2. Significant differences were also found between rocker sole shoes and normal or barefoot standing, which supports H3. This study contributes to the understanding of how and why EnHL is a useful measure to monitor neuromuscular control of balance. [ABSTRACT FROM AUTHOR]

The lateral prefrontal cortex and the basal ganglia are known to be important for response selection processes, also in dual-task situations. However, response selection in dual-task situations can be achieved using different modes ranging from a parallel selection to a more serial selection of responses. Nothing is known whether differences in these processing modes during dual-tasking have distinct functional neuroanatomical correlates. In this fMRI study we analyzed performance in a psychological refractory period paradigm. In this paradigm we design a PRP task where we vary the frequency of short and long stimulus onset asynchronies between the two tasks. Using mathematical constraints we interpret the effects of this manipulation with respect to processing modes ranging from more serial to more parallel response selection. Contrastingly these blocks showed that response selection in dual-tasking under the constraint of more parallel processing is mediated by mechanisms operating at the striatal level, while response selection under the constraint of more serial processing is mediated via mechanisms operating in the lateral prefrontal cortex. The results suggest that lateral prefrontal and striatal regions are 'optimized' for a certain processing modes in dual tasking. [ABSTRACT FROM AUTHOR]

Background: The number of chronic musculoskeletal pain sites (nCMSP) is reportedly associated with risk of falls. Older participants in community-based research show a wide range of physical functions, but few studies have focused on the risk of falls in older adults with normal motor function (NMF). Clarification of the effects of pain on dual-tasking performance is also important, given the strong link between falls and dual-tasking. Aims: The objectives were to investigate the associations between: (1) nCMSP and falls; and (2) nCMSP and dual-task performance in older adults with NMF. Methods: A total of 112 older adults with NMF (44 men, 68 women; 73.4 ± 4.6 years) were classified as fallers ( n = 22) or non-fallers ( n = 90) according to their fall history. Musculoskeletal pain in the lower body was assessed using questions ascertaining pain in musculoskeletal sites (back, hip, knee, foot, or toe). Participants were assigned to three pain groups according to nCMSP. Basic physical performances and gait performances (normal gait, fast gait, or dual-task gait) were measured. Results: The nCMSP represented a significant risk factor for falls according to logistic regression modeling after adjusting for the five chair stand test and fear of falls. The nCMSP was not associated with any gait variables. Discussion: Potential fall risk may be increased by nCMSP, even in older adults with NMF. Pain-related reduction in attention resources may not represent a risk factor for falls among older adults with NMF. Conclusions: The nCMSP represents a potential risk factor for falls in older adults with NMF. [ABSTRACT FROM AUTHOR]

Gait performance exhibits patterns within the stride-to-stride variability that can be indexed using detrended fluctuation analysis (DFA). Previous work employing DFA has shown that gait patterns can be influenced by constraints, such as natural aging or disease, and they are informative regarding a person's functional ability. Many activities of daily living require concurrent performance in the cognitive and gait domains; specifically working memory is commonly engaged while walking, which is considered dual-tasking. It is unknown if taxing working memory while walking influences gait performance as assessed by DFA. This study used a dual-tasking paradigm to determine if performance decrements are observed in gait or working memory when performed concurrently. Healthy young participants ( N = 16) performed a working memory task (automated operation span task) and a gait task (walking at a self-selected speed on a treadmill) in single- and dual-task conditions. A second dual-task condition (reading while walking) was included to control for visual attention, but also introduced a task that taxed working memory over the long term. All trials involving gait lasted at least 10 min. Performance in the working memory task was indexed using five dependent variables (absolute score, partial score, speed error, accuracy error, and math error), while gait performance was indexed by quantifying the mean, standard deviation, and DFA α of the stride interval time series. Two multivariate analyses of variance (one for gait and one for working memory) were used to examine performance in the single- and dual-task conditions. No differences were observed in any of the gait or working memory dependent variables as a function of task condition. The results suggest the locomotor system is adaptive enough to complete a working memory task without compromising gait performance when walking at a self-selected pace. [ABSTRACT FROM AUTHOR]

Behavioral studies suggest that postural control requires increased cognitive control and visuospatial processing with aging. Consequently, performance can decline when concurrently performing a postural and a demanding cognitive task. We aimed to identify the neural substrate underlying this effect. A demanding cognitive task, requiring visuospatial transformations, was performed with varying postural loads. More specifically, old and young subjects performed mental rotations of abstract figures in a seated position and when standing on a force platform. Additionally, functional magnetic resonance imaging (fMRI) was used to identify brain regions associated with mental rotation performance. Old as compared to young subjects showed increased blood oxygenation level-dependent (BOLD) responses in a frontoparietal network as well as activations in additional areas. Despite this overall increased activation, they could still modulate BOLD responses with increasing task complexity. Importantly, activity in left lingual gyrus was highly predictive ( r = −0.83, adjusted R = 0.65) of the older subjects' degree of success in mental rotation performance when shifting from a sitting to a standing position. More specifically, increased activation in this area was associated with better performance, once postural load increased. [ABSTRACT FROM AUTHOR]

Patients with early Parkinson’s disease (PD) may not complain of gait difficulties but subtle gait abnormalities may be revealed as part of a “preclinical gait syndrome” when they are challenged by dual tasks. 21 early PD patients ( n = 21, mean age 63.5 years, H&Y 1.62, disease duration <5 years, mean UPDRS-III 7.7) who did not have gait complaints were as compared to age- and gender-matched healthy controls ( n = 21). Memory function was not different between the two groups. Under normal walking conditions, there were no significant differences in gait parameters between the patients and the control group. In both groups, normalized gait velocity decreased in response to dual tasking in a parallel fashion ( p < 0.001). Similarly, gait variability increased in both groups with dual tasking although not statistically significant. In PD patients, the performance of an additional task resulted in an increased number of cadences ( p = 0.04), a reduction in swing time ( p = 0.02) and cycle time ( p = 0.04) compared with the control group but there was no significant reduction in normalized velocity. Stride width also increased in the PD patients. The addition of a cognitive task may affect certain aspects of gait and is able to elicit subclinical deficits in early PD patients. In an attempt to maintain velocity, early PD patients develop compensatory mechanisms by increasing cadence and decreasing swing time and cycle time. Increased step width helps support balance, and prevents going beyond the base-of-support which may predispose to unsteadiness and falls. We propose that these findings occur as part of a spectrum of a “preclinical gait syndrome” and longitudinal studies are needed to assess the predictive values of these early markers of gait deficits. [ABSTRACT FROM AUTHOR]

Three experiments examined interactions between posture control in upright stance and a concurrent location memory task. Healthy young participants stood upright and memorized the locations of dots presented on a computer screen. In the retrieval phase, they indicated whether arrows presented on the screen would pass through any of the memorized locations. Postural sway variability was measured either during the retention period or during retrieval. Relative to not performing the memory task, postural sway variability increased in the retention period when the eyes were closed, but remained unaffected when the eyes were open. During retrieval, postural sway variability was reduced relative to the no-memory-task condition. Results were interpreted in terms of dual-task costs associated with maintaining multiple frames of reference. [ABSTRACT FROM AUTHOR]

Aims: To study and compare both mean performance measures as well as intra-individual variability measures of stride length and reaction time in vulnerable recurrent and non-recurrent older fallers. Methods: Stride length during walking and walking while dual-tasking (GAlTRite®) and choice reaction time (CANTAB®) were assessed in geriatric outpatients and their informal caregivers (n=60, ≥60 yrs). Logistic regression and Receiver Operating Characteristic (ROC) analysis were used to generate models with mean performance measures and intra-individual variability measures (coefficients of variation; CV=[sd/mean]x100)), as risk factors for recurrent falls. Results: Reaction-time CV was higher in recurrent fallers than in non-recurrent fallers: 21.3% [9.3-47.7] vs 15.8% [8.3-34.9] (p=0.04). Also, stride-length CV was higher in recurrent fallers during performance of the verbal fluency dual-task: 4.5% [1.2-31.4] vs 3.5% [0.9-9.7](p=0.017). The model with CVs provided an explained variance of 23.7%, and an area under the curve (AUC) of 0.73, which was higher than that of the model including mean performance measures (8.6% and 0.65 respectively). Conclusions: Older recurrent fallers are characterized by increased within-task variability in reaction time and stride length while dual- tasking. In addition, variability in performance is a more sensitive measure in discrimination of recurrent falls than mean performance itself, suggesting deterioration in neurocognitive regulation mechanisms as part of the causal pathway for recurrent falls. [ABSTRACT FROM AUTHOR]

Tuberous sclerosis complex (TSC) is a genetic disorder associated with mTOR over-activation and disruption of MAPK, PI3K and AMPK signalling. Children with TSC have significant deficits on neuropsychological attention tasks, particularly dual tasking. Here we investigated attentional skills and related behaviours in daily life in normally intelligent adults with TSC and matched controls using the Test of Everyday Attention for Children (TEA-Ch) and the Attention-Deficit Scales for Adults (ADSA). No group differences were demonstrated on selective or sustained attention tasks carried out alone. However, adults with TSC performed significantly worse when these tasks were combined in a cross-modal dual task condition. On the ADSA the TSC group had significantly worse scores on several subscales (attention/concentration, behaviour/disorganization, academic and emotional behaviours) compared to controls and these correlated with dual task performance, indicating a clear impact of dual task deficits on attention-related behaviours in daily life. The presence or absence of epilepsy did not influence dual task performance or attention-deficits in daily life. Taken together with similar findings in children, results suggest that dual task difficulties are a core feature of the neuropsychological phenotype of TSC. [ABSTRACT FROM AUTHOR]

While operating, surgeons are required to make cognitive decisions and often are interrupted to attend to questions from other members of the health care team. Technical automatization may be achieved by experienced surgeons such that these distractions have little effect on performance of either the surgical or the cognitive task. This study assessed the effect of adding a distracting cognitive task on performance of a basic laparoscopic skill by novice and experienced surgeons. In this study, 31 novice (medical students in postgraduate years [PGYs] 1–2) and 9 experienced (fellows/attendants and PGYs 4–5) laparoscopic surgeons practiced the Fundamentals of Laparoscopic Surgery (FLS) laparoscopic peg transfer task until their scores stabilized. The mean normalized score after five repetitions then was recorded. The subjects also were tested on the number of mathematical addition questions they could answer in 1 min. This was repeated five times, with the mean number of questions attempted and the accuracy (% correct) recorded. The laparoscopic and addition tasks then were performed concurrently five times. Data, presented as mean ± standard deviation, were analyzed using Student’s t-test. A p value less than 0.05 was considered statistically significant. After practice to stable peg transfer performance, the baseline peg transfer score was higher in the experienced group (98 ± 6 vs 87 ± 12; p < 0.01). There were no baseline differences between the groups in the number of math questions attempted in 1 min (10 ± 2 vs 9 ± 2; p = 0.55) or the number of correct answers (9 ± 3 vs 8 ± 3; p = 0.36). The comparison of baseline performance and dual-task performance showed that the experienced surgeons had no decline in peg transfer score (98 ± 6 vs 97 ± 6; p = 0.48), number of questions attempted in 1 min (10 ± 2 vs 9 ± 3; p = 0.32), or number of correct answers (9 ± 3 vs 8 ± 3; p = 0.46). In contrast, dual-tasking among the novices was associated with a decrease in the number of questions attempted (9 ± 2 vs 8 ± 2; p < 0.01) and the number of correct answers (8 ± 3 vs 7 ± 2; p = 0.02), and with no change in the peg transfer score (87 ± 12 vs 88 ± 8; p = 0.38) compared with baseline. Distraction significantly decreased a novice’s ability to process cognitively based math problems, whereas there was no effect on experienced subjects. This occurred despite the fact that the novice group had practiced to high-level peg transfer scores at baseline. This suggests that the experienced surgeons had achieved automatization of the peg transfer basic surgical skill to a level that cognitive distraction did not affect performance of either task. The experienced surgeons were able to attend equally to both tasks, whereas the novices attended to the surgical task at the expense of some aspects of cognitive task performance. [ABSTRACT FROM AUTHOR]