Mental Tracking Research Articles

The Effects of Fatigue and Cognitive Tasks on Neurocognitive Outcomes during Orthostatic Challenge

Orthostatic challenge (OC), also known as orthostatic hypertension, is a blood pressure drop that results in pooling of blood in the lower extremities leading to oxygen deprivation in the brain, impairing neurovestibular functions which are critical for determining the position and motion of the head, and therefore the rest of the body; these functions are necessary for an astronaut to perform their job (Mark & Heldt, 2005). Acute orthostatic intolerance is a change in blood flow pressure that affects 64% of astronauts on short-range missions and 80% of astronauts on long-range missions. Orthostatic challenge is encountered when astronauts return from the microgravity of space to the gravity of the earth’s atmosphere, this transition can alter physiological responses, which can worsen with fatigue and have a detrimental effect on performance of critical piloting tasks. The existing countermeasures utilized to lessen the impact of orthostatic intolerance are primarily focused around health promotion. Before the flight begins, astronauts are trained for improved physical fitness with an emphasis on aerobic exercises to maintain optimal cardiac function (Convertino, 2002). The objective of this study was to discern the types of cognitive functions affected by fatigue that should be studied further, starting with measurements of the psychomotor tasks needed for control, maneuvering, and the demands of high-level cognitive skills required for space flight. Data from this study would allow for greater exploration of the neural correlates of cognitive stressors that are encountered during OC especially under the fatigued conditions of long-range space flight. If fatigue does adversely affect neural correlates of performance during OC, then the types of cognitive stressors placed on the subject will influence that relationship and should be explored further to develop different training protocols for better countermeasures to assist astronauts with the transition out of microgravity. Sixteen college-aged athletes (8 M, 8 F) were recruited for this study. Participation in the study was limited to the university athletic groups to represent highly physically fit individuals. A two-way repeated measures design was employed to test the interactive effects of physical fatigue (control versus fatigue) and cognitive task (mental arithmetic versus psychomotor tracking) on neurocognitive outcomes during orthostatic challenge. In the fatigue condition, participants were physically fatigued for one hour prior to undergoing the orthostatic challenge to simulate the fatigued condition experienced by astronauts. We found that the presence of fatigue adversely affected participant’s ability to perform the psychomotor countermeasure tasks, over mental arithmetic, during short duration OC. The fatigued state was evident in the changes seen in the monitoring tools; heart rate and heart rate variability and PFC oxygenated hemoglobin levels. The inability to utilize countermeasures leaves astronauts vulnerable and potentially unable to overcome the orthostatic challenge during the transition from microgravity to gravity with an inability to combat fatigue with the countermeasures utilized. Findings obtained here with help identify the nature and extent to which fatigue impacts an astronaut’s ability to employ countermeasures used to combat orthostatic challenge and how effective those countermeasures will be in the fatigued state. These findings can provide the rationale for developing different countermeasures that are less susceptible to fatigue as well as new training and physical interventions for astronauts to employ while they are in space flight to better combat the cumulative effects of extended exposure to microgravity.

The impact of intelligence on memory and executive functions of children with temporal lobe epilepsy: Methodological concerns with clinical relevance.

Patients with TLE are prone to have lower IQ scores than healthy controls. Nevertheless, the impact of IQ differences is not usually considered in studies that compared the cognitive functioning of children with and without epilepsy. This study aimed to determine the effect of using IQ as a covariate on memory and attentional/executive functions of children with TLE. Thirty-eight children and adolescents with TLE and 28 healthy controls paired as to age, gender, and sociodemographic factors were evaluated with a comprehensive neuropsychological battery for memory and executive functions. The authors conducted three analyses to verify the impact of IQ scores on the other cognitive domains. First, we compared performance on cognitive tests without controlling for IQ differences between groups. Second, we performed the same analyses, but we included IQ as a confounding factor. Finally, we evaluated the predictive value of IQ on cognitive functioning. Although patients had IQ score in the normal range, they showed lower IQ scores than controls (p=0.001). When we did not consider IQ in the analyses, patients had worse performance in verbal and visual memory (short and long-term), semantic memory, sustained, divided and selective attention, mental flexibility and mental tracking for semantic information. By using IQ as a covariate, patients showed worse performance only in verbal memory (long-term), semantic memory, sustained and divided attention and in mental flexibility. IQ was a predictor factor of verbal and visual memory (immediate and delayed), working memory, mental flexibility and mental tracking for semantic information. Intelligence level had a significant impact on memory and executive functioning of children and adolescents with TLE without intellectual disability. This finding opens the discussion of whether IQ scores should be considered when interpreting the results of differences in cognitive performance of patients with epilepsy compared to healthy volunteers.

Interoception in pathological health anxiety.

According to cognitive-behavioral models, pathological health anxiety is triggered and maintained by the perception of mostly mild and benign bodily sensations that are misinterpreted as signs of illness. Arguably, abnormalities in interoception may account for this misguided preoccupation with somatic sensations. Using a multimethod approach, the current study investigated possible abnormalities in interoception in patients with pathological health anxiety (PHA; n = 51) and healthy participants (n = 56). Different types of interoception were assessed with a heartbeat-tracking task and a signal-detection task for nonspecific skin conductance fluctuations (NSCFs task). Patients compared with healthy participants showed a more liberal interoceptive response bias for NSCFs, t(79) = 2.32, p = .02, d = 0.53, 95% confidence interval (CI) (0.30, 0.68). Specifically, patients with a comorbid anxiety disorder compared with healthy participants exhibited a significantly higher interoceptive sensitivity for NSCFs, t(57) = 3.12, p < .01, d = 0.89, 95% CI (0.54, 1.12). No evidence for higher interoceptive sensitivity in PHA (neither in the heartbeat mental tracking task nor in the NSCF task) was observed after accounting for comorbid anxiety disorders. The findings suggest that higher interoceptive sensitivity might not be specific to health anxiety, but rather associated with factors shared with the anxiety disorders. Biased (i.e., more liberal) interoceptive processing appears more specific to health anxiety, but further studies using larger sample sizes and a multimethod approach for the assessment of interoception are needed to more completely unravel the role of interoception in health anxiety. (PsycINFO Database Record

Walking impairs cognitive performance among people with multiple sclerosis but not controls

People with multiple sclerosis (MS) complain of problems completing two tasks simultaneously; sometimes called ‘dual-tasking’ (DT). Previous research in DT among people with MS has focused on how adding a cognitive task interferes with gait and few have measured how adding a motor task could interfere with cognition. We aimed to determine the extent to which walking affects a concurrent working memory task in people with MS compared to healthy controls. We recruited MS participants (n=13) and controls (n=10) matched by age (±3years), education (±3years) and gender. Participants first completed the cognitive task (subtracting 7’s from the previous number) and then again while walking on an instrumented walkway. Although there were no baseline differences in cognition or walking between MS participants and controls, MS participants demonstrated a 52% decrease in number of correct answers during DT (p<0.001). Mental Tracking Rate (% correct answers/min) correlated strongly with MS-related disability measured using the Expanded Disability Status Scale (EDSS; r(11)=−0.68, p<0.01). We propose that compromised mental tracking during walking could be related to limited neural resource capacity and could be a potentially useful outcome measure to detect ecologically valid dual tasking impairments.

ADORA2A genotype modulates interoceptive and exteroceptive processing in a fronto-insular network

Facilitated processing of interoceptive and exteroceptive information in the salience network is suggested to promote the development of anxiety and anxiety disorders. Here, it was investigated whether the adenosine 2 A receptor gene (ADORA2A) 1976T/C (rs5751876) variant – previously associated with anxiety disorders and anxiety-related phenotypes as well as general attentional efficiency –was involved in the regulation of this network.In detail, fMRI recordings of 65 healthy participants (female=35) were analyzed regarding ADORA2A genotype effects on brain connectivity related to (1) interoceptive processing in terms of functional connectivity resting-state fMRI, and (2) exteroceptive processing using dynamic causal modeling in task-based fMRI. In a subsample, cardiac interoceptive accuracy was furthermore measured via the Mental Tracking Task.ADORA2A genotype was found to modulate a fronto-insular network at rest (interoceptive processing) and while performing an executive control task (exteroceptive processing). Across both modalities, the ADORA2A TT risk genotype was associated with increased connectivity between the insula and the prefrontal cortex. The strength in connectivity correlated with interoceptive accuracy.It is concluded that alterations in fronto-insular connectivity are modulated by both the adenosinergic system and interoceptive accuracy. Thus, fronto-insular connectivity in synopsis with ADORA2A genotypic information could serve as combined biomarkers for personalized treatment approaches in anxiety disorders targeting exteroceptive and interoceptive dysfunction.

Association of Vitamin D Status with Dual Task Physical Performance in Older Adults

ObjectiveTo evaluate the association of vitamin D status with age‐related changes in mobility and higher order cognitive function using a single and dual task physical performance test.MethodsAfter consenting, participants completed the baseline assessments that included serum levels of vitamin D, vitals, anthropometrics and body composition, as well as completing surveys to evaluate physical activity, depressive symptoms and fear of falling. Participants performed in random order the physical performance tests, which included 1) walking (single gait task); 2) counting backwards from 50 by 1 (single cognitive task); and 3) walking while counting backwards from 50 by 1 (dual task). The dual task physical performance variables measured were: 1) dual task gait velocity; 2) single task gait velocity; 3) difference in dual and single task gait velocity; 4) dual task counting rate; 5) single task counting rate; 6) difference in dual and single counting rate. Paired t‐tests were used to compare single and dual task variables within the whole population and each vitamin D status group. Spearman's correlations, independent t‐tests, repeated measures ANOVAs and multiple logistic regressions were used to examine the relationship between vitamin D insufficiency (25OHD&lt;30ng/mL) and sufficiency (25OHD≥30ng/mL) and dual task physical performance variables. The significance level was set at α≤0.05, and statistical analyzes were performed using SPSS 21.ResultsThe mean +/− SD of serum vitamin D levels were 30.73 +/− 8.73 ng/ml and 46% of the participants were vitamin D insufficient. Dual and single task counting rate were significantly lower in the vitamin D insufficient group compared to the sufficient group (mean difference: −0.14, P=0.018 and mean difference: −0.06, P=0.028, respectively). Using Spearman correlations, a slower single (r=0.258, P=0.011) and dual counting rate (r=0.278, P=0.006) were significantly associated with vitamin D insufficiency.ConclusionsCognitive performance for dual or single tasking were worse in the vitamin D insufficient group. Since counting backward is a mental tracking task, which is a component of executive function, our results support a relationship between vitamin D insufficiency and executive dysfunction.

Assessing the Relationship between Vitamin D Status and Impairments in Cognitive and Physical Performance in Older Adults Using a Dual Task Physical Performance Test.

Vitamin D deficiency has been associated with an increased risk of falls in older adults. Several studies have demonstrated an association between vitamin D deficiency and gait and cognitive impairments, which are two risk factors for falls in the elderly. There is lack of research about the role of vitamin D in cognitive function in the context of mobility. The purpose of this study was to evaluate the association between vitamin D status with the age-related changes in mobility through higher order cognitive function using a dual task physical performance test. Cross-sectional. Community-dwelling older adult population located in Miami, Fl. Healthy participants over the age of 55 (n=97) who participated in the parent interventional study. Participants completed assessments that included serum levels of vitamin D, surveys, and dual task physical performance tests. Spearman's correlations, independent t-tests, repeated measures ANOVAs and multiple logistic regressions were used to examine the relationship between vitamin D insufficiency (25-hydroxyvitamin D <30 ng/ml) and sufficiency (≥30 ng/ml) and dual task physical performance variables. The significance level was set at α=0.05. There were no significant associations between vitamin D insufficiency and gait velocity during either task. Using Spearman correlations, slower single (P=0.011) and dual task counting rates (P=0.006) were significantly associated with vitamin D insufficiency. Independent t-tests showed dual and single task counting rates were significantly lower in the vitamin D insufficient group compared to the sufficient group (P=0.018 and P=0.028, respectively). The results for the ANOVAs indicated that velocities and counting rates were not significantly different by vitamin D status (Wilk's Lambda =0.999; F (1, 95) =.11, P=.740) (Wilk's Lambda =.999, F(1,95)=.13, P=.718). Vitamin D status was not significantly associated with dual task physical performance (defined as the difference in dual and single task) in gait velocity (OR=1.00, 95% CI: 0.98; 1.02, P=0.772) and counting rate (OR=1.684, 95% CI: 0.15; 19.57, P=0.677), when controlling for confounders. Since counting backward is a mental tracking task, which is a component of executive function, our results suggest a relationship between vitamin D insufficiency and executive dysfunction. Executive dysfunction has been previously associated with fall risks in the elderly, and it could be a possible mediator between vitamin D and falls. Our data suggest that cognition may play a significant role in vitamin D's influence on falls, while motor function may play a lesser role.

Mental tracking of dynamic features

Mental tracking of dynamic features

Interoceptive sensitivity, body image dissatisfaction, and body awareness in healthy individuals.

Relationships among interoceptive sensitivity (IS), body image dissatisfaction, body mass index (BMI), and self-reported body awareness were investigated in a cross-sectional study. Eighty-two Norwegian high school students and 70 Hungarian undergraduate university students participated in the study. Subjects completed two questionnaires (Body Image Ideals Questionnaire - BIQ; Body Awareness Questionnaire - BAQ) followed by the assessment of interoceptive sensitivity using the Mental Tracking Method (MTM). An inverse, medium-level relationship between body image dissatisfaction and IS was found in both the Norwegian and the Hungarian samples. The relationships between IS and self-reported body awareness, and between body image dissatisfaction and BMI were uniformly non-significant in both samples. Predictors of body image dissatisfaction were resting heart rate, gender, and IS in the regression analysis after controlling for BMI, age, and nationality. The negative relationship between IS and body image dissatisfaction described in patients with anorexia nervosa also exists in healthy individuals. There is no direct connection between IS and self-reported body awareness.

Improving heartbeat perception in patients with medically unexplained symptoms reduces symptom distress

Distortions in interoceptive accuracy have been linked to somatoform disorders. In line with cognitive theories of symptom formation in somatoform disorders, decreases in interoceptive accuracy have recently been observed to co-occur with more severe symptom reports. The current study tested the hypothesis that experimentally increasing interoceptive accuracy should decrease symptom severity in somatoform disorders. Twenty-nine patients with somatoform disorders were instructed in a newly developed heartbeat perception training procedure. Heartbeat perception, as a proxy for interoceptive accuracy, was assessed with a mental tracking task. Although there were no significant differences between the training group and a waiting control group (n=23) regarding increases in heartbeat perception, health anxiety served as a moderator and significant reductions in state symptom reports were observed after training. These findings suggest a relation between lower interoceptive accuracy and the perception of bodily symptoms in somatoform disorders.

Internal focus of attention in anxiety-sensitive females up-regulates amygdale activity: an fMRI study.

Cognitive behavioral models of panic disorder (PD) stress the importance of an increased attentional focus towards bodily symptoms in the onset and maintenance of this debilitating anxiety disorder. In this fMRI mental tracking paradigm, we looked at the effects of focusing one's attention internally (interoception) vs. externally (exteroception) in a well-studied group at risk for PD-that is anxiety-sensitive females (AS-high). We hypothesized that AS-high subjects compared to control subjects will present higher arousal and decreased valence scores during interoception and parallel higher activity in brain areas which are associated with fear and interoception. 24 healthy female students with high levels of anxiety sensitivity and 24 healthy female students with normal levels of anxiety sensitivity serving as control group were investigated by 3T fMRI. Subjects either focused their attention on their heartbeats (internal condition) or on neutral tones (external condition). Task performance was monitored by reporting the number of heartbeats or tones after each block. State of arousal and emotional valence were also assessed. The high anxiety-sensitive group reported higher arousal scores compared to controls during the course of the experiment. Simultaneously, fMRI results indicated higher activation in anxiety-sensitive participants than in controls during interoception in a network of cortical and subcortical brain regions (thalamus, amygdala, parahippocampus) that overlaps with known fear circuitry structures. In particular, the activity of the right amygdala was up-regulated. Future prospective-longitudinal studies are needed to validate the role of the amygdala for transition to disorder. Attention to internal body functions up-regulates the activity of interoceptive and fear-relevant brain regions in anxiety-sensitive females, a high-risk group for the development of anxiety disorders.

The Relationship Between Sexual Concordance and Interoception in Anxious and Nonanxious Women

Sexual concordance refers to the association between physiological and self-reported sexual arousal. Women typically exhibit lower sexual concordance scores than men. There is also a sex difference in interoception--awareness of (nonsexual) physiological states or responses--such that women, compared with men, tend to be less aware of and less accurate at detecting changes in their physiological responses. Women with anxiety problems tend to have better interoceptive abilities than nonanxious women. To investigate whether women's lower sexual concordance is associated with interoception using a sample likely to show high variation in interoceptive abilities. Sixteen anxious and 15 nonanxious women were presented with twelve 90 seconds sexual and nonsexual film clips while their genital response, heart rate, and respiration rate were measured. A heartbeat mental tracking task was also employed. Genital response was measured with a vaginal photoplethysmograph. Heart rate was measured with an electrocardiogram and respiration rate with a thermistor. Participants estimated their physiological responses after each film. A mental tracking task was also used to assess participants' awareness of heart rate. Within-subject correlations were computed for each physiological/self-reported response combination. Overall, sexual concordance (i.e., the correlation between genital responses and perceptions of genital response) was not significantly associated with heart rate awareness or respiration rate awareness. Anxious women did not exhibit significantly higher sexual concordance or heart rate awareness than nonanxious women; the nonanxious women actually exhibited higher respiration rate awareness. The results suggest that sexual concordance may be a distinct phenomenon from interoception and in need of its own explanation.

Baseline Heartbeat Perception Accuracy and Short-Term Outcome of Brief Cognitive-Behaviour Therapy for Panic Disorder with Agoraphobia

Increased heartbeat perception accuracy (HBP-accuracy) may contribute to the pathogenesis of Panic Disorder (PD) without or with Agoraphobia (PDA). Extant research suggests that HBP-accuracy is a rather stable individual characteristic, moreover predictive of worse long-term outcome in PD/PDA patients. However, it remains still unexplored whether HBP-accuracy adversely affects patients' short-term outcome after structured cognitive behaviour therapy (CBT) for PD/PDA. To explore the potential association between HBP-accuracy and the short-term outcome of a structured brief-CBT for the acute treatment of PDA. We assessed baseline HBP-accuracy using the "mental tracking" paradigm in 25 consecutive medication-free, CBT-naive PDA patients. Patients then underwent a structured, protocol-based, 8-session CBT by the same therapist. Outcome measures included the number of panic attacks during the past week, the Agoraphobic Cognitions Questionnaire (ACQ), and the Mobility Inventory-Alone subscale (MI-alone). No association emerged between baseline HBP-accuracy and posttreatment changes concerning number of panic attacks. Moreover, higher baseline HBP-accuracy was associated with significantly larger reductions in the scores of the ACQ and the MI-alone scales. Our results suggest that in PDA patients undergoing structured brief-CBT for the acute treatment of their symptoms, higher baseline HBP-accuracy is not associated with worse short-term outcome concerning panic attacks. Furthermore, higher baseline HBP-accuracy may be associated with enhanced therapeutic gains in agoraphobic cognitions and behaviours.

The effect of aging on verbal fluency in South Indians.

Semantic verbal fluency tests are used as a measure of cognitive function to assess language and executive function. Secondary to increasing life spans, there are increasing numbers of older individuals at work places. Our study was done to assess the effect of aging on verbal fluency in South Indians. 50 controls aged 20-50 years (Group I) , 50 subjects aged 60-75 years (Group II) and 50 subjects aged above 75 years (Group III) of both sexes who were cognitively unimpaired with a minimum 6 th standard education took part in the study. The semantic category verbal fluency test and verbal mental tracking test were administered. Comparison of the verbal fluency scores between Group I versus Group II (p=0.00) and Group I versus Group III (p=0.00) was significant. Comparison of the verbal mental tracking scores between Group I versus Group II (p=0.002) and between Group I versus Group III (p=0.00) was also significant. However there were no significant differences in the number of perseverative errors (repetitions) between controls and subjects. Our study therefore showed that while verbal fluency declined significantly with aging, there was no evidence of cognitive inflexibility and executive dysfunction with aging. Keywords-Aging, Cognition, Cognitive inflexibility, Executive dysfunction, semantic verbal fluency test.

Memory in children with temporal lobe epilepsy is at least partially explained by executive dysfunction

An association between memory and executive dysfunction (ED) has been demonstrated in patients with mixed neurological disorders. We aimed to investigate the impact of ED in memory tasks of children with temporal lobe epilepsy (TLE). We evaluated 36 children with TLE and 28 controls with tests for memory, learning, attention, mental flexibility, and mental tracking. Data analysis was composed of comparison between patients and controls in memory and executive function; correlation between memory and executive function tests; and comparison between patients with mild and severe ED in memory tests. Children with TLE had worse performance in focused attention, immediate and delayed recall, phonological memory, mental tracking, planning, and abstraction. Planning, abstraction, and mental tracking were correlated with visual and verbal memory. Children with severe ED had worse performance in verbal and visual memory and learning tests. This study showed that ED was related to memory performance in children with TLE.

Is interoceptive awareness really altered in somatoform disorders? Testing competing theories with two paradigms of heartbeat perception.

Alterations in the perception of body signals (i.e., interoceptive awareness [IA]) are considered crucial for the development and maintenance of somatoform disorders (SFDs). However, competing theories come to different conclusions about whether IA is increased or decreased in SFDs. The present study investigated IA in 23 patients with SFDs (as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) and in 27 healthy controls. IA was reliably assessed with two well-established heartbeat perception paradigms (heartbeat discrimination task and mental tracking task). The results of both paradigms showed no evidence for increased IA in patients with SFDs. Correlational analyses revealed that having a higher number of somatoform symptoms was significantly linked to lower (rather than higher) IA in SFDs. These findings are in line with recent cognitive approaches to SFDs that stress the importance of biased schema-guided processing of interoceptive information.

Translational attention: From experiments in the lab to helping the symptoms of individuals with Tourette’s syndrome

Over the past decade my colleagues and I have been able to demonstrate, using objective scientific paradigms, how topdown processes such as suggestion and expectation seem to override bottom-up effects in highly hypnotizable people. As appealing and as intriguing such demonstrations may be, however, these exemplars usually span a small set of circumscribed tasks, which are usually entrenched within the purview of experimental psychology. In his commentary, moreover, Kirsch (2011) emphasised the importance of including moderately suggestible participants in experiments involving hypnosis. In this paper we attempt to sketch out some preliminary data to support the potential generalizability of these findings to clinical situations. As a case in point, we focus on the neurodevelopmental motor disorder of Tourette’s Syndrome (TS), which is part of a spectrum of motor impairments, ranging from simple transient motor tics to chronic debilitating symptoms, and which affect 0.5–24% of school-aged children around the world (Freeman et al., 2000; Jankovic, 1997; Kurlan et al., 2001; Robertson, 2003; Shapiro, Shapiro, Young, & Feinberg, 1988; Singer & Walkup, 1991). Conveniently, tic severity in TS peaks around the age of 11–12 years of age – a time marked by heightened compliance with suggestion and susceptibility to hypnosis (see Kohen & Olness, 2011; Raz, 2012). Individuals with TS often have difficulty with executive functions, a term comprising a number of cognitive and behavioural constructs that include mental tracking, sustained attention, working memory, planning and organisation, goal-directedness, cognitive flexibility during problem-solving, impulse control, and self-regulation. Childhood motor disorders, including TS, are more widespread than is commonly acknowledged (Spessot & Peterson, 2006). The clinical hallmark of TS is the presence of motor or phonic tics: repetitive, stereotypedmotions or vocalisations (APA, 2000). Motor tics range from simple motions, such as blinking or shoulder-shrugging, to more complicated motions, such as jumping, and kicking (Jankovic, 2001). Phonic tics range from simple squeaking or grunting sounds to echoing and, more rarely, cursing (Freeman et al., 2000; Jankovic, 2001). In addition, many individuals with TS report sensations of mounting urges or psychological tension prior to ticking (Hallett, 2001; Leckman, 2002). TS is often co-morbid with attention-deficit hyperactivity disorder (ADHD), obsessive–compulsive disorder (OCD) or both (Robertson, 2003). The combination of TS with any co-morbidity increases the risk of problems such as anger management, self-injurious behaviour, and sleep disorders (Freeman et al., 2000). Thus, the management of TS is of critical concern to healthcare professionals. While pharmacological options exist for the treatment of TS (e.g., haloperidol, pimozide, or clonidine), general consensus posits that such therapies are suboptimal, and prominent researchers have lamented that ‘‘medication therapies for TS are, frankly, woefully inadequate’’ (Peterson & Cohen, 1998). Drug efficacy is inconsistent and unpredictable, and at best, offers only symptomatic relief (Phelps, 2008). Benefits often come at the expense of intolerable side-effects, including sedation, parkinsonism, tardive dyskinesia, cognitive dulling, dry mouth, fatigue, dizziness, weight gain, and metabolic problems (Swain, Scahill, Lombroso, King, & Leckman, 2007). TS specialists hence recognise the need for alternatives and therapeutic adjuncts (Phelps, 2008).

Meta‐analysis of type and complexity of a secondary task during walking on the prediction of elderly falls

Dual-tasking probes divided attention and causes performance changes that are associated with an increased risk for falls in the elderly. There is no systematic review investigating the effect of task type and complexity on the prediction of elderly falls. This article synthesizes research evidence regarding this issue on the contents of dual-tasking walking. Relevant studies were systematically identified from electronic databases of Medline, PubMed, CINAHL, Cochrane CENTRAL and PsycINFO, and the reference lists of identified articles. The selection criteria were defined a priori. Two independent reviewers classified task types based on properties for cognitive demand, assessed the methodological quality with a customized checklist, and calculated the odds ratio of fall prediction. There was one study of reaction time, one of discrimination and decision-making, 10 of mental tracking, three of verbal fluency and five of manual tasks. The methodological heterogeneity was manifested in the selection criteria, faller classification, tasks and measures, resulting in substantial heterogeneity (I(2) 87-92%). Meta-analyses resulted in a significant pooled odds ratio 1.33 (95% CI 1.18-1.50). The mental tracking task was the only type that yielded a significant odds ratio 3.30 (95% CI 2.00-5.44). Running meta-analyses separately for simple and difficult mental tracking task showed similar odds ratios. The mental tracking task yielded significant dual-task-related changes for fall prediction. Most studies successively used an appropriate level of task complexity specific to the specified population of interest. More research is required for definite conclusions regarding the effect of task type and complexity.

Postshunt Cognitive and Functional Improvement in Idiopathic Normal Pressure Hydrocephalus

Improvement in gait after shunt placement has been well documented in idiopathic normal pressure hydrocephalus (iNPH); however, controversy remains regarding the extent and pattern of postsurgical cognitive changes. Conflicting findings may be explained by variability in both test selection and follow-up intervals across studies. Furthermore, most investigations lack a control group, making it difficult to disentangle practice effects from a true treatment effect. To examine postshunt changes in a sample of well-characterized iNPH participants compared with a group of age- and education-matched healthy control subjects. We identified 12 participants with iNPH undergoing shunt placement and 9 control participants. All participants were evaluated with comprehensive neuropsychological testing and standardized gait assessment at baseline and were followed up for 6 months. Repeated-measures analysis of variance revealed a significant group- (iNPH and control) by-time (baseline and 6 months) interaction for Trailmaking Test B: (P < .003) and Symbol Digit Modalities (P < .02), with greater improvement in iNPH participants relative to control subjects. In addition, the iNPH group showed greater improvement in gait (P < .001) and caregivers reported improved activities of daily living (P < .01) and reduced caregiver distress (P < .01). This study demonstrates improvements in mental tracking speed and sustained attention 6 months after shunt placement in iNPH. The present investigation is the first study to use a controlled design to show that cognitive improvement in iNPH is independent of practice effects. Furthermore, these findings indicate functional and quality-of-life improvements for both the shunt responder and their caregiver.

Gait adaptations to simultaneous cognitive and mechanical constraints

Previous studies have shown that walking is not a purely automatic motor task but places demands on sensory and cognitive systems. We set out to investigate whether complex walking tasks, as when walking down a steeper gradient while performing a concurrent cognitive task, would demand gait adaptation beyond those required for walking under low-challenge conditions. Thirteen healthy young individuals walked at their self-selected speed on a treadmill at different inclinations (0, -5 and -10%). Gait spatio-temporal measures, pelvis angular excursion, and sacral centre of mass (CoM) motion were acquired while walking or while walking and performing a mental tracking task. Repeated-measures ANOVAs revealed that decreasing treadmill inclination from 0 to -10% resulted in significant decreased walking speed (P < 0.001), decreased stride length (P < 0.001), increased pelvis tilt (P = 0.006) and obliquity variability (P = 0.05), decreased pelvis rotation (P = 0.02), and increased anterio-posterior (A-P) CoM displacement (P = 0.015). Compared to walking alone, walking under dual-task condition resulted in increased step width (P < 0.001), and increased medio-lateral (M-L) CoM displacement (P = 0.039) regardless of inclination grade, while sagittal plane dynamics did not change. Findings suggest that gait adapts differently to cognitive and mechanical constraints; the cognitive system is more actively involved in controlling frontal than sagittal plane gait dynamics, while the reverse is true for the mechanical system. Finally, these findings suggest that gait adaptations maintain the ability to perform concurrent tasks while treadmill walking in healthy young adults.