Selective Alterations Within Executive Functions in Adolescents With Excess Weight

Increasing evidence underscores overlapping neurobiological pathways to addiction and obesity. In both conditions, reward processing of preferred stimuli is enhanced, whereas the executive control system that would normally regulate reward‐driven responses is altered. This abnormal interaction can be greater in adolescence, a period characterized by relative immaturity of executive control systems coupled with the relative maturity of reward processing systems. The aim of this study is to explore neuropsychological performance of adolescents with excess weight (n = 27, BMI range 24–51 kg/m²) vs. normal‐weight adolescents (n = 34, BMI range 17–24 kg/m²) on a comprehensive battery of executive functioning tests, including measures of working memory (letter‐number sequencing), reasoning (similarities), planning (zoo map), response inhibition (five‐digit test (FDT)–interference and Stroop), flexibility (FDT–switching and trail‐making test (TMT)), self‐regulation (revised‐strategy application test (R‐SAT)), and decision‐making (Iowa gambling task (IGT)). We also aimed to explore personality traits of impulsivity and sensitivity to reward. Independent sample t‐ and Z Kolmogorov–Smirnov tests showed significant differences between groups on indexes of inhibition, flexibility, and decision‐making (excess‐weight participants performed poorer than controls), but not on tests of working memory, planning, and reasoning, nor on personality measures. Moreover, regression models showed a significant association between BMI and flexibility performance. These results are indicative of selective alterations of particular components of executive functions in overweight adolescents.     

A Computerized Test of Design Fluency

Tests of design fluency (DF) assess a participant’s ability to generate geometric patterns and are thought to measure executive functions involving the non-dominant frontal lobe. Here, we describe the properties of a rapidly administered computerized design-fluency (C-DF) test that measures response times, and is automatically scored. In Experiment 1, we found that the number of unique patterns produced over 90 s by 180 control participants (ages 18 to 82 years) correlated with age, education, and daily computer-use. Each line in the continuous 4-line patterns required approximately 1.0 s to draw. The rate of pattern production and the incidence of repeated patterns both increased over the 90 s test. Unique pattern z-scores (corrected for age and computer-use) correlated with the results of other neuropsychological tests performed on the same day. Experiment 2 analyzed C-DF test-retest reliability in 55 participants in three test sessions at weekly intervals and found high z-score intraclass correlation coefficients (ICC = 0.79). Z-scores in the first session did not differ significantly from those of Experiment 1, but performance improved significantly over repeated tests. Experiment 3 investigated the performance of Experiment 2 participants when instructed to simulate malingering. Z-scores were significantly reduced and pattern repetitions increased, but there was considerable overlap with the performance of the control population. Experiment 4 examined performance in veteran patients tested more than one year after traumatic brain injury (TBI). Patients with mild TBI performed within the normal range, but patients with severe TBI showed reduced z-scores. The C-DF test reliably measures visuospatial pattern generation ability and reveals performance deficits in patients with severe TBI.     

Trimethylthiazoline supports conditioned flavor avoidance and activates viscerosensory, hypothalamic, and limbic circuits in rats

Interoceptive stimuli modulate stress responses and emotional state, in part, via ascending viscerosensory inputs to the hypothalamus and limbic forebrain. It is unclear whether similar viscerosensory pathways are recruited by emotionally salient exteroceptive stimuli, such as odors. To address this question, we investigated conditioned avoidance and central c-Fos activation patterns in rats exposed to synthetic trimethylthiazoline (TMT), an odiferous natural component of fox feces. Experiment 1 demonstrated that rats avoid consuming novel flavors that previously were paired with TMT exposure, evidence that TMT supports conditioned flavor avoidance. Experiment 2 examined central neural systems activated by TMT. Odor-naive rats were acutely exposed to low or high levels of TMT or a novel nonaversive control odor and were perfused with fixative 60-90 min later. A subset of rats received retrograde neural tracer injections into the central nucleus of the amygdala (CeA) 7-10 days before odor exposure and perfusion. Brain sections were processed for dual-immunocytochemical detection of c-Fos and other markers to identify noradrenergic (NA) neurons, corticotropin-releasing hormone (CRH) neurons, and retrogradely labeled neurons projecting to the CeA. Significantly greater proportions of medullary and pontine NA neurons, hypothalamic CRH neurons, and CeA-projecting neurons were activated in rats exposed to TMT compared with activation in rats exposed to the nonaversive control odor. Thus the ability of TMT to support conditioned avoidance behavior is correlated with significant odor-induced recruitment of hypothalamic CRH neurons and brain stem viscerosensory inputs to the CeA.     

Using the Hard, Randy, and Rittler Test to Evaluate Color Vision in Capuchins (Cebus libidinosus)

The identification of color vision types in primates is fundamental to understanding the evolution and biological function of color perception. The Hard, Randy, and Rittler (HRR) pseudoisochromatic test categorizes human color vision types successfully. Here we provide an experimental setup to employ HRR in a nonhuman primate, the capuchin (Cebus libidinosus), a platyrrhine with polymorphic color vision. The HRR test consists of plates with a matrix composed of gray circles that vary in size and brightness. Differently colored circles form a geometric shape (X, O, or Δ) that is discriminated visually from the gray background pattern. The ability to identify these shapes determines the type of dyschromatopsy (deficiency in color vision). We tested six capuchins in their own cages under natural sunlight. The subjects chose between two HRR plates in each trial: one with the gray pattern only and the other with a colored shape, presented on the left or right side at random. We presented the test 40 times and calculated the 95?% confidence limits for chance performance based on the binomial test. We also genotyped all subjects for exons 3 and 5 of the X-linked opsin genes. The HRR test diagnosed two subjects as protan dichromats (missing or defective L-cone), three as deutan dichromats (missing or defective M-cone), and one female as trichromat. Genetic analysis supported the behavioral data for all subjects. These findings show that the HRR test can be applied to diagnose color vision in nonhuman primates.     

Thyroid hormones and cognitive functioning in healthy, euthyroid women: a correlational study

Thyroid hormones (THs) play a critical role in differentiation, growth, and metabolism of animal and human organ systems, including the brain. Although associations between normal levels of THs and cognitive functions in healthy elderly individuals have been reported, the findings are inconsistent, possibly due to differences in study designs. Because thyroid disease occurs more frequently in women, the goal of the present study was to examine the relationship between levels of THs and performance on neuropsychological tests in 122 healthy, euthyroid women whose mean age was 51 years. Higher levels of free T3 were positively associated with longer completion times (slower performance) on Trail Making Test - Part A (p = 0.006) and Part B (p = 0.032) and on the Tower of London test (p = 0.002). Higher levels of thyroglobulin antibodies (TgAb) were positively correlated with more errors on the Trail Making Test Part B (p = 0.000), on the Word Fluency test (p = 0.023), and on the Design Fluency test (p = 0.045). No significant correlations between TH levels and scores on mood, verbal memory, or working memory measures were observed. The findings point to a possible link between THs and cognitive processes that are mediated primarily by frontal cortex, areas associated with executive function tasks, and suggest that elevations in levels of free T3 and TgAB within the normal range may negatively influence executive functions.     

Differences in planning performance,a neurocognitive endophenotype,are associated with a functional variant in PER3 gene

Performance alterations in executive function have been studied as potential endophenotypes for several neuropsychiatric diseases. Planning is an important component of executive function and has been shown to be affected in diseases such as attention deficit hyperactivity disorder, schizophrenia, obsessive–compulsive disorder and Parkinson’s disease. Several genes related to dopaminergic systems, such as COMT, have been explored as candidates for influencing planning performance. The circadian clock gene PERIOD3 (PER3) has been shown to be associated with several complex behaviors in humans and could be involved in different signaling mechanisms. In this study, we evaluated the possible association between a functional polymorphism in the PER3 gene (PER3-VNTR, rs57875989) and performance in a commonly used test of planning (Tower of London, TOL) in 229 healthy subjects from Bogotá, Colombia. PER3-VNTR genotyping was carried out with conventional PCR and all participants completed the TOL test using the computerized Psychology Experiment Building Language (PEBL) battery. A linear regression model was used for the analysis of association with the SNPStats program. We found that 4/4 genotype carriers showed a better performance and made fewer moves, in comparison to 4/5 and 5/5 genotype carriers (p?=?0.003). These results appear to be independent from effects of this polymorphism on self-reported average hours of sleep during work days in our sample. This is the first evidence of an association between PER3-VNTR and planning performance in a sample of healthy subjects and our results are consistent from previous findings for alterations in other cognitive domains. Future studies examining additional genes could lead to the identification of novel molecular underpinnings of planning in healthy subjects and in patients with neuropsychiatric disorders.     

Genetic effects on information processing speed are moderated by age – converging results from three samples

Information processing is a cognitive trait forming the basis of complex abilities like executive function. The Trail Making Test (TMT) is a well‐established test of information processing with moderate to high heritability. Age of the individual also plays an important role. A number of genetic association studies with the TMT have been performed, which, however, did not consider age as a moderating factor. We report the results of genome‐wide association studies (GWASs) on age‐independent and age‐dependent TMT performance in two population‐representative community samples (Munich Antidepressant Response Signature, MARS: N₁ = 540; Ludwig Maximilians University, LMU: N₂ = 350). Age‐dependent genome‐wide findings were then evaluated in a third sample of healthy elderly subjects (Sydney Memory and Ageing Study, Sydney MAS: N₃ = 448). While a meta‐analysis on the GWAS findings did not reveal age‐independent TMT associations withstanding correction for multiple testing, we found a genome‐wide significant age‐moderated effect between variants in the DSG1 gene region and TMT‐A performance predominantly reflecting visual processing speed (rs2199301, P_{meta‐analysis} = 1.3 × 10^?7). The direction of the interaction suggests for the minor allele a beneficial effect in younger adults turning into a detrimental effect in older adults. The detrimental effect of the missense single nucleotide polymorphism rs1426310 within the same DSG1 gene region could be replicated in Sydney MAS participants aged 70–79, but not in those aged 80 years and older, presumably a result of survivor bias. Our findings demonstrate opposing effects of DSG1 variants on information processing speed depending on age, which might be related to the complex processes that DSG1 is involved with, including cell adhesion and apoptosis.     

Poor trail making test performance is directly associated with altered dual task prioritization in the elderly--baseline results from the TREND study

Background

Deterioration of executive functions in the elderly has been associated with impairments in walking performance. This may be caused by limited cognitive flexibility and working memory, but could also be caused by altered prioritization of simultaneously performed tasks. To disentangle these options we investigated the associations between Trail Making Test performance—which specifically measures cognitive flexibility and working memory—and dual task costs, a measure of prioritization.

Methodology and Principal Findings

Out of the TREND study (Tuebinger evaluation of Risk factors for Early detection of Neurodegenerative Disorders), 686 neurodegeneratively healthy, non-demented elderly aged 50 to 80 years were classified according to their Trail Making Test performance (delta TMT; TMT-B minus TMT-A). The subjects performed 20 m walks with habitual and maximum speed. Dual tasking performance was tested with walking at maximum speed, in combination with checking boxes on a clipboard, and subtracting serial 7 s at maximum speeds. As expected, the poor TMT group performed worse when subtracting serial 7 s under single and dual task conditions, and they walked more slowly when simultaneously subtracting serial 7 s, compared to the good TMT performers. In the walking when subtracting serial 7 s condition but not in the other 3 conditions, dual task costs were higher in the poor TMT performers (median 20%; range −6 to 58%) compared to the good performers (17%; −16 to 43%; p<0.001). To the contrary, the proportion of the poor TMT performance group that made calculation errors under the dual tasking situation was lower than under the single task situation, but higher in the good TMT performance group (poor performers, −1.6%; good performers, +3%; p = 0.035).

Conclusion

Under most challenging conditions, the elderly with poor TMT performance prioritize the cognitive task at the expense of walking velocity. This indicates that poor cognitive flexibility and working memory are directly associated with altered prioritization.     

Clinical Significance of Fronto-Temporal Gray Matter Atrophy in Executive Dysfunction in Patients with Chronic Kidney Disease: The VCOHP Study

Background & Objectives

It is well known that cognitive impairment in patients with chronic kidney disease (CKD) is characterized by executive dysfunction, rather than memory dysfunction, although the precise mechanism of this remains to be elucidated. The purpose of the present study is to examine the correlation between gray matter volume (GMV) and executive function in CKD patients.

Design, Setting, Participants, Measurements

This cross-sectional study recruited 95 patients with non-dialysis-dependent CKD (NDD-CKD) with no history of cerebrovascular disease, who underwent brain magnetic resonance imaging (MRI) and Trail Making Test (TMT) in the VCOHP Study. The subjects underwent brain MRI and TMT part A (TMT-A) and part B (TMT-B). The segmentation algorithm from Statistical Parametric Mapping 8 software was applied to every T1-weighted MRI scan to extract tissue maps corresponding to gray matter, white matter, and cerebrospinal fluid. GMV was normalized by dividing by the total intracranial volume, calculated by adding GMV, white matter volume, and cerebrospinal fluid space volume. Then, normalized whole-brain GMV was divided into four categories of brain lobes; frontal, parietal, temporal, and occipital. We assessed the correlation between normalized GMV and TMT using multivariable regression analysis.

Results

Normalized whole-brain GMV was significantly inversely correlated to the scores of TMT-A, TMT-B, and ΔTMT (TMT-B minus TMT-A). These correlations remained significant even after adjusting for relevant confounding factors. Normalized frontal and temporal GMV, but not parietal and occipital GMV, were significantly inversely correlated with TMT-A, TMT-B, and ΔTMT using multivariable regression analysis.

Conclusions

The present study demonstrates the correlation between normalized GMV, especially in the frontal and temporal lobes, and executive function, suggesting that fronto-temporal gray matter atrophy might contribute to executive dysfunction in NDD-CKD.     

Dopamine Genes (DRD2/ANKK1-TaqA1 and DRD4-7R) and Executive Function: Their Interaction with Obesity

Obesity is a multifactorial disease caused by the interaction between genotype and environment, and it is considered to be a type of addictive alteration. The A1 allele of the DRD2/ANKK1-TaqIA gene has been associated with addictive disorders, with obesity and with the performance in executive functions. The 7 repeat allele of the DRD4 gene has likewise been associated with the performance in executive functions, as well as with addictive behaviors and impulsivity. Participants were included in the obesity group (N = 42) if their body mass index (BMI) was equal to or above 30, and in the lean group (N = 42) if their BMI was below 25. The DRD2/ANKK1-TaqIA and DRD4 VNTR polymorphisms were obtained. All subjects underwent neuropsychological assessment. Eating behavior traits were evaluated. The ‘DRD2/ANKK1-TaqIA A1-allele status’ had a significant effect on almost all the executive variables, but no significant ‘DRD4 7R-allele status’ effects were observed for any of the executive variables analyzed. There was a significant ‘group’ x ‘DRD2/ANKK1-TaqIA A1-allele status’ interaction effect on LN and ‘group’ x ‘DRD4 7R-allele status’ interaction effect on TMT B-A score. Being obese and a carrier of the A1 allele of DRD2/ANKK1-TaqIA or the 7R allele of DRD4 VNTR polymorphisms could confer a weakness as regards the performance of executive functions.     

Discrimination of Image Orientation in the Presence of Distractors

We studied the influence of additional images (distractors) on the recognition of test objects, which included low-contrast Landolt circles with sizes of 1.1, 1.5, and 2.2 angular degrees and were presented eccentrically at 13.2 degrees from fixation. The distractors were either Landolt Cs or full circles with the same spatial characteristics. The distance between the test objects and the distractors varied from 2.2 to 24.2 angular degrees. The subjects were required to report the orientation of the tests (simple task) or to report the orientation of the tests and the shape of the distractor (dual task). The first group of subjects performed both simple and dual tasks, while the second group only performed the simple task. A significant deterioration of performance was recorded at all tested separations in both tasks; it was more pronounced in the dual task. The percent of correct responses was lower when Landolt circles were distractors as compared with full circles. The subjects tended to report the orientation of the distractors instead of tests in the cases of small and large separations. The recognition of distractors was also performed at a lower level in the cases of small and large distances. The data show that attention contributes to the task performance in two ways: the features of tests and distractors are integrated, or the tests are substituted by distractors.     

The Five-Point Test: Reliability,Validity and Normative Data for Children and Adults

The present study provides normative data from a sample of 257 healthy children and 608 adults on a modified version of the Five-Point Test (5PT). The 5PT is a structured and standardized test measuring figural fluency functions. Interrater reliability, test-retest-reliability and construct validity of this measure were analyzed. The sensitivity of the task for cognitive disturbances of patients with neurological diseases was proven by analyzing the test performance in the 5PT of patients with Parkinson''s disease. Finally, normative data stratified by age and corrected for education level is provided. The results of the present study confirm the value of the 5PT in the measurement of figural fluency functions in clinical examination and neuropsychological research.     

The Effects of Chronic Exercise on Attentional Networks

The aim of this study was to test the hypothesis that chronic physical exercise improves attentional control in young healthy participants. To do this, we compared the performance of physically active and passive participants in the Attentional Network Task, which allows for the assessment of the executive, orienting and alerting networks. The results showed a selective positive effect of exercise on the executive network. These results extend the evidence gathered in children, older adults and certain clinical populations suggesting that exercise can also improve attentional control in healthy young adults.     

Fear-like behavioral responses in mice in different odorant environments: Trigeminal versus olfactory mediation under low doses

Odors can have repulsive effects on rodents based on two complementary adaptive behaviors: the avoidance of predator odors (potentially dangerous) and the avoidance of trigeminal stimulants (potentially noxious). The present study aimed to compare the behavioral effects on mice of odors according to their trigeminal properties and ecological significance. We used three different odors: 2,4,5-trimethylthiazoline (TMT: a fox feces odor frequently used to elicit fear-induced behaviors), toluene (a strong stimulant of the trigeminal system) and phenyl ethyl alcohol (PEA: a selective stimulant of the olfactory system). First, we checked preference and avoidance behaviors in mice with and without anosmia towards these odors to ensure their olfactory/trigeminal properties. Secondly, we used a standard test (open-field and elevated plus-maze) to assess the behaviors of mice when exposed to these odors. The results show that the anosmic and control mice both avoided TMT and toluene odors. In the open-field and the elevated plus-maze, mice exhibited "anxious" behaviors when exposed to TMT. Conversely, exposure to PEA induced "anxiolytic" effects confirmed by low blood corticosterone levels resulting from completion of the elevated plus-maze. Compared with TMT exposure, toluene exposure induced moderate "anxious" effects.     

The divergent impact of COMT Val158Met on executive function in children with and without attention‐deficit/hyperactivity disorder

Children with attention‐deficit/hyperactivity disorder (ADHD) usually display deficits in executive function (EF), which are primarily mediated by prefrontal cortex (PFC). The functional polymorphism of catechol‐O‐methyltransferase (COMT), Val158Met (rs4680), leads to observed polymorphic differences in the degradation of dopamine within PFC. This study aimed to explore the effect of rs4680 on EF using case–control design. In addition, considering the dynamic development of EF, we also attempted to investigate whether this genetic influence changes during development or not. A total of 597 ADHD children and 154 unaffected controls were recruited. The EF was evaluated using Rey–Osterrieth complex figure test (RCFT), trail making test (TMT) and Stroop color and word test for working memory, shifting and inhibition. Association between genotype and EF was analyzed using analysis of covariance (ancova ). The results showed significant interaction effect of genotype and ADHD diagnosis on RCFT performance (P < 0.001). However, the associated genotypes between ADHD and controls were divergent. In ADHD, the Met carriers performed better than the Val homozygotes on detail immediate [(10.38 ± 6.90) vs. (9.33 ± 6.92), P = 0.007] and detail delay [(9.96 ± 6.86) vs. (8.86 ± 6.89), P = 0.004], while Val homozygotes showed better performance compared with Met carrier controls [for detail immediate (14.55 ± 6.18) vs. (11.10 ± 6.45), P<0.001; for detail delay (14.31 ± 5.96) vs. (11.31 ± 6.96), P = 0.001]. We did not find significant interaction between genetic variant and development. COMT Val158Met (rs4680) may have divergent effect on working memory in ADHD children compared with healthy controls.     

Is the cognitive function of older patients affected by antihypertensive treatment? Results from 54 months of the Medical Research Council's trial of hypertension in older adults.

OBJECTIVE--To establish whether initiation of treatment with diuretic or beta blocker is associated over 54 months with change in cognitive function. DESIGN--A cognitive substudy, nested within a randomised, placebo controlled, single blind trial. SETTING--226 general practices from the Medical Research Council''s general practice research framework. SUBJECTS--A subset of 2584 subjects sequentially recruited from among the 4396 participants aged 65-74 in the trial of treatment of hypertension in older adults. The 4396 subjects were randomised to receive diuretic, beta blocker, or placebo. Subjects had mean systolic pressures of 160-209 mm Hg and mean diastolic pressures <115 mm Hg during an eight week run in. OUTCOME MEASURES--The rate of change in paired associate learning test (PALT) and trail making test part A (TMT) scores (administered at entry and at 1, 9, 21, and 54 months) over time. RESULTS--There was no difference in the mean learning test coefficients (rate of change of score over time) between the three treatments: diuretic -0.31 (95% confidence interval -0.23 to -0.39), beta blocker -0.33 (-0.25 to -0.41), placebo -0.30, (-0.24 to -0.36). There was also no difference in the mean trail making coefficients (rate of change in time taken to complete over time) between the three groups: diuretic -2.73 (95% confidence interval -3.57 to -1.88), beta blocker -2.08 (-3.29 to -0.87), placebo -3.01, (-3.69 to -2.32). A less conservative protocol analysis confirmed this negative finding. CONCLUSION--Treating moderate hypertension in older people is unlikely to influence, for better or for worse, subsequent cognitive function.     

Effects on discrimination performance of selective attention to tactile features

This study examined selective attention to tactile dimensions by combining a selective cueing paradigm with a test of integrality. In Experiment 1, subjects selectively attended to changes in the frequency or duration of pairs of vibrotactile stimuli and identified the higher frequency or longer duration stimulus. In Experiment 2, using surface gratings in an identical experimental procedure, subjects identified the rougher or longer duration stimulus. In both experiments, greater performance accuracy was found on trials where the cue correctly (valid) predicted the changing dimension, vs incorrectly (invalid) cued or no-cue (neutral) trials. More errors on the invalidly vs neutrally cued trials show the cost of focal attention. Increases in performance on validly vs neutrally cued trials show a benefit of filtering irrelevant stimuli in the cued conditions. Results effectively demonstrate focal attention to tactile features. Tests of integrality, in terms of the effects of correlated change in both dimensions, showed no redundancy gain for either vibrotactile or grating tasks, suggesting that frequency and roughness are separable from stimulus duration. Interference of negative correlated change for frequency but not roughness discriminations may be explained by differences in task difficulty.     

The Shape Trail Test: Application of a New Variant of the Trail Making Test

Objective

The Trail making test (TMT) is culture-loaded because of reliance on the Latin alphabet, limiting its application in Eastern populations. The Shape Trail Test (STT) has been developed as a new variant. This study is to examine the applicability of the STT in a senile Chinese population and to evaluate its potential advantages and disadvantages.

Method

A total of 2470 participants were recruited, including 1151 cognitively normal control (NC), 898 amnestic mild cognitive impairment (aMCI), and 421 mild Alzheimer disease (AD) patients. Besides the STT, the Mini mental state examination and a comprehensive neuropsychological battery involving memory, language, attention, executive function and visuospatial ability were administered to all the participants. In a subgroup of 100 NC and 50 AD patients, both the STT and the Color Trail Test (CTT) were performed.

Results

In NC, the time consumed for Part A and B (STT-A and STT-B) significantly correlated with age and negatively correlated with education (p<0.01). STT-A and B significantly differed among the AD, aMCI and NC. The number that successfully connected within one minute in Part B (STT-B-1 min) correlated well with STT-B (r = 0.71, p<0.01) and distinguished well among NC, aMCI and AD. In the receiver operating characteristic curve analysis, the AUCs (area under the curve) for STT-A, STT-B, and STT-B-1min in identifying AD were 0.698, 0.694 and 0.709, respectively. The STT correlated with the CTT, but the time for completion was longer.

Conclusion

The TMT is a sensitive test of visual search and sequencing. The STT is a meaningful attempt to develop a “culture-fair” variant of the TMT in addition to the CTT.     

Characteristics of the performance of a dual task, voluntary postural control, and calculation by patients with consequences of traumatic brain injury

Comprehensive clinical (MMSE, FIM and MPAI-3 and Berg scales) and stabilographic evaluation was carried out in 14 patients (with a mean age of 25.7 ± 4.7 years) with consequences of traumatic brain injury (TBI) in comparison with the data on 40 healthy subjects (with a mean age of 29.8 ± 2.5 years) performing separate and dual tasks, including voluntary postural control and calculation. According to the clinical evaluation, all the patients were divided into two groups: group 1 with a moderate deficit (eight patients) and group 2 with a marked functional deficit (six patents). The parameters of the quality of motor and, especially, cognitive subtask performance in both separate and dual tasks were lower than the normative values in all the patients, especially in group 2 patients. Types of dual tasks where the quality of the motor subtask performance was higher than in separate tasks were revealed in healthy subjects and some group 1 patients. The stabilographic parameters characterizing the quality of subtask performance by TBI patients were revealed. Dual tasks could be used for diagnostic purposes such as an additional method for evaluating the adaptive capacity of TBI patients, and certain types of dual tasks could become a promising approach for the recovery of TBI patients at the late stages of rehabilitation.