Visual Attention Test Research Articles

Spatiotemporal oscillatory dynamics of visual selective attention during a flanker task

The flanker task is a test of visual selective attention that has been widely used to probe error monitoring, response conflict, and related constructs. However, to date, few studies have focused on the selective attention component of this task and imaged the underlying oscillatory dynamics serving task performance. In this study, 21 healthy adults successfully completed an arrow-based version of the Eriksen flanker task during magnetoencephalography (MEG). All MEG data were pre-processed and transformed into the time-frequency domain. Significant oscillatory brain responses were imaged using a beamforming approach, and voxel time series were extracted from the peak responses to identify the temporal dynamics. Across both congruent and incongruent flanker conditions, our results indicated robust decreases in alpha (9–12Hz) activity in medial and lateral occipital regions, bilateral parietal cortices, and cerebellar areas during task performance. In parallel, increases in theta (3–7Hz) oscillatory activity were detected in dorsal and ventral frontal regions, and the anterior cingulate. As per conditional effects, stronger alpha responses (i.e., greater desynchronization) were observed in parietal, occipital, and cerebellar cortices during incongruent relative to congruent trials, whereas the opposite pattern emerged for theta responses (i.e., synchronization) in the anterior cingulate, left dorsolateral prefrontal, and ventral prefrontal cortices. Interestingly, the peak latency of theta responses in these latter brain regions was significantly correlated with reaction time, and may partially explain the amplitude difference observed between congruent and incongruent trials. Lastly, whole-brain exploratory analyses implicated the frontal eye fields, right temporoparietal junction, and premotor cortices. These findings suggest that regions of both the dorsal and ventral attention networks contribute to visual selective attention processes during incongruent trials, and that such differential processes are transient and fully completed shortly after the behavioral response in most trials.

Increased risk for age-related impairment in visual attention associated with mild traumatic brain injury: Evidence from saccadic response times.

It was hypothesized that risk for age-related impairment in attention would be greater among those with remote history of mild TBI than individuals without history of head injury. Twenty-seven adults with remote history of mild TBI and a well-matched comparison group of 54 uninjured controls completed a computerized test of visual attention while saccadic and manual response times were recorded. Within the mild TBI group only, older age was associated with slower saccadic responses and poorer saccadic inhibition. Saccadic slowing was mitigated in situations where the timing and location of attention targets was fully predictable. Mild TBI was not associated with age-related increases in risk for neuropsychological impairment or neurobehavioral symptoms. These results provide preliminary evidence that risk for age-related impairment in visual attention may be higher among those with a history of mild TBI. Saccadic measures may provide enhanced sensitivity to this subtle form of cognitive impairment.

Attentional performance may help to identify duloxetine responders in chronic pain fibromyalgia patients.

Long-term pain affects brain in response to attention tasks. This study aimed to verify the relationship between performance in a computerized visual attention test (CVAT) and response to duloxetine in fibromyalgia patients. Duloxetine is approved for the treatment but the response is not immediate. Patients were drawn from a sample of 74 patients with chronic pain. These patients were selected because they kept their subjective perceptions of pain as severe after 1week of duloxetine treatment. All patients were tested in the CVAT on two occasions: the first appointment and 7days after starting duloxetine. After 6weeks, the group was subdivided into responsive and non-responsive patients. Responsiveness was defined by a subjective improvement from severe to low-intensity or no-pain after the sixth week of duloxetine treatment. Responsive patients showed objective attentional improvements in the second test. Non-respondent patients did not exhibit changes in attentional performance in the second test as compared to the first one. The data were interpreted considering that persistent pain in fibromyalgia is maintained by central sensitization that may be associated with functional changes in the dorsolateral prefrontal cortex and the posterior parietal cortex. In responsive patients, duloxetine treatment may be responsible for a partial recovery of these regions. This may explain the early attentional improvement observed in the responsive patients after 1week of treatment. Thus, attentional performance may help to predict which patients will respond to duloxetine treatment even before they can demonstrate subjective improvements in pain perception. This study shows that an improvement in an attentional test is a reliable predictor of the treatment response even without any improvement in the perception of pain.

Assessing infant cognitive development after prenatal iodine supplementation

Little information is available on infant behavioral development outcomes of prenatal iodine supplementation in regions of mild to moderate iodine deficiency. Studies performed to date, all of which relied on global developmental assessments, have yielded inconsistent findings with regard to psychomotor development, negative findings with regard to mental development, and no information as to the development of specific cognitive functions. Our review of these studies leads us to suspect that the use of global developmental assessments might partially explain the negative and inconsistent findings. To identify cognitive processes that might be sensitive to prenatal iodine supplementation, we examined the timing of thyroid hormone action on specific brain systems. The development of infant visual attention is sensitive to thyroid hormone during the early prenatal period, when the fetus is entirely dependent on maternal thyroid hormone. For this reason, infant visual attention has the potential to be a sensitive measure of infant outcomes in prenatal iodine supplementation studies. We suggest the assessment of infant visual attention, with follow-up examination of childhood executive functions, as a means of capturing the effects of maternal iodine deficiency and prenatal iodine supplementation on specific cognitive processes. In particular, we propose comparison of infant performance on global developmental tests and specialized tests of visual attention in pilot trials of prenatal iodine supplementation in regions of mild to moderate iodine deficiency. Only by comparing the 2 types of tests side by side will it be possible to establish whether the use of a sensitive measure of infant visual attention will increase the reliability of such supplementation studies. Recognizing that exposure misclassification may also provide a partial explanation for the inconsistent neurodevelopmental outcomes in previous studies, we suggest that urinary iodine concentration or creatinine-corrected iodine excretion be monitored regularly in such trials throughout the prenatal period.

Visual Processing in Generally Gifted and Mathematically Excelling Adolescents

Little empirical data are available concerning the cognitive abilities of gifted individuals in general and especially those who excel in mathematics. We examined visual processing abilities distinguishing between general giftedness (G) and excellence in mathematics (EM). The research population consisted of 190 students from four groups of 10th- to 12th-grade students who differed in their G and EM levels. The students performed a battery of visual processing tests: visual-spatial memory, visual speed of information processing (SVIP), visual perception (VP), and visual attention (VA). The results demonstrate that EM type has a significant effect on the Backward Corsi-Span, whereas G type has a main effect on the Pattern-Recognition test and d2-CP (concentration performance) and d2-E (number of errors) scores in the attention test. SVIP and the fluctuation rate in VA tests (d2-FR) were associated with both G and EM types. The current study identified two different components of visual processing that were accordingly termed Visual-Serial and Pattern-Recall. It seems that G-EM students can be characterized by superior performance on Visual-Serial processing.

The developmental relationship between DHEA and visual attention is mediated by structural plasticity of cortico-amygdalar networks

Humans and the great apes are the only species demonstrated to exhibit adrenarche, a key developmental event leading to increased production of dehydroepiandrosterone (DHEA), suggesting that this hormone may play an important evolutionary role. Similarly, visual attention networks have been shown to evolve in a human-specific manner, with some anatomical connections and elements of cortical organization exclusive to our species. Existing studies of human brain development support the notion that DHEA shows significant uptake in cortical structures and the amygdala, and as such, could be involved in the bottom-up regulation of visual attention. Here we examined associations between DHEA, structural covariance of the amygdala with whole-brain cortical thickness, and tests of visual attention, in a longitudinal sample of typically developing children and adolescents 6–22 years of age. We found that DHEA predicted covariance between amygdalar volume and the left occipital pole, right somatosensory parietal cortex and right anterior cingulate cortex. Amygdala-occipital covariance predicted visual awareness; amygdala-parietal covariance predicted visuo-motor dexterity and processing speed; amygdala-prefrontal covariance predicted global attentional impairment. Further, effects of DHEA were above and beyond those of age and sex, as well as distinct from those of pubertal stage, estradiol and testosterone. These findings support the notion that DHEA may play a unique role in shaping amygdala-dependent cortical plasticity and in regulating ‘bottom-up’ visual attention processes from childhood to young adulthood.

Functional outcome at school age of neonatal post-hemorrhagic ventricular dilatation

BackgroundSpecific knowledge about the functional outcome of preterm born children with post-hemorrhagic ventricular dilatation (PHVD) is lacking. ObjectivesTo determine functional outcome at school age in children with post-hemorrhagic ventricular dilatation and to identify whether PHVD characteristics increased the risk for deficits. MethodsSingle-center case–control study. Included were preterm children born between 1996 and 2003 who had PHVD in their neonatal period. The controls were children matched for gestation, gender, and year of birth. At school age, using standardized tests and questionnaires, we assessed intelligence, attention, verbal memory, executive functioning, visual perception, visuomotor integration, motor skills, and behavior. ResultsOf 34 children with PHVD 28 survived, three of whom could not be tested at school age (one child's parents declined and two were lost to follow-up). At a mean age of 10years (6–14years) the total and verbal IQs of the remaining 25 children (17 boys, 8 girls) were significantly lower compared to controls (difference in total IQ—14 points, verbal IQ—9 points, P=0.001and P=0.009, respectively). After adjustment for possible confounders, the performance of the PHVD group was poorer on visual perception and attention tests. Selective attention showed a trend toward risk of borderline and abnormal scores (OR 4.03, 95%-CI 0.84–19.2). Within the PHVD group, total IQ was significantly lower (P=0.048) in those who had undergone surgical intervention (n=12). ConclusionAt school age, intelligence, attention, and visual perception were more affected in the PHVD group than in the matched controls. Surgical intervention was associated with lower IQ scores.

Identification of Students at Risk for Attention Deficit Disorder with Hyperactivity Using the Response to Intervention Model (RTI)

The use of Response to Intervention Model (RTI) has been described in the literature as an important tool for early identification of students at risk of learning problems. However, such studies are rare in the Brazilian population. This study aimed to use the response to intervention model (RTI) as an early identification procedure for Attention Deficit Disorder (ADD) students from 1st grade level of elementary school in Brazilian population. A total of 118 students participated of this study, aged between 6:0 and 6:11 (years:months), from 1st grade level, of both genders. The study was divided into three phases. In the first phase, all students were tested individually with Visual Attention Test software (TAVIS) composed of three tasks: selective attention, alternating attention and sustained attention. Because it was an initial study, all students were submitted to the Remediation Program with Attention and Working Memory (RAWM) in phase 2. The program consists of attention skills and phonological working memory skills (7 individual sessions, 40 minutes each). In phase 3, the students were submitted to the TAVIS. As results, from 118 students, 106 students concluded all 3 phases, which 34 students (32%) met the risk criteria for ADD after being submitted to the program. Of these, 34 students, 15 students (46.7%) responded to the intervention, while 19 students (59.3%) not responded. These students who not responded to the intervention program were sent to multidisciplinary care for monitoring and subsequent confirmation of the diagnosis of ADD. The findings of this study able us to conclude that RTI model can be used as an early identification tool for student at risk of attention in the early years literacy deficit.

Brain-training for physical performance: a study of EEG-neurofeedback and alpha relaxation training in athletes

"In recent years, EEG-neurofeedback training (EEG-NFB) has been increasingly used to optimize various brain functions. Better performance in various activities was also reported after relaxation trainings, another popular method in therapeutic practice. Both these methods are used as a part of professional coaching in sports training centers. In the present study, we aimed to evaluate the impact of such holistic training on physiological (EEG) and behavioral measures on semi-professional athletes. EEG-NFB paradigm was intended for amplification of the amplitudes of SMR (12–15 Hz) and beta1 (13–20 Hz) bands and simultaneous reduction of the amplitude of theta (4–7.5 Hz) and beta2 (20–30 Hz). Participation in NFB sessions was accompanied with self-administration of relaxing, audio-visual stimulation after each daily athletic training session. The training program resulted in the increase of alpha and beta1 power of trained participants when assessed in rest with eyes-closed. In eyes – open state, participants of the trained group maintained the same level in all frequency bands, in opposite to the control subjects, whose power decreased in the second measurement in beta1 band when compared to the first one. The trained group exhibited greater reduction of reaction times in a test of visual attention than the control group and showed improvement in several performance measures of Kraepelin's work-curve, used to evaluate speed, effectiveness and work accuracy. Together, these results present initial support for the use of holistic, neurophysiological training in sports workout."

Modality-specificity of Selective Attention Networks.

Objective: To establish the modality specificity and generality of selective attention networks.Method: Forty-eight young adults completed a battery of four auditory and visual selective attention tests based upon the Attention Network framework: the visual and auditory Attention Network Tests (vANT, aANT), the Test of Everyday Attention (TEA), and the Test of Attention in Listening (TAiL). These provided independent measures for auditory and visual alerting, orienting, and conflict resolution networks. The measures were subjected to an exploratory factor analysis to assess underlying attention constructs.Results: The analysis yielded a four-component solution. The first component comprised of a range of measures from the TEA and was labeled “general attention.” The third component was labeled “auditory attention,” as it only contained measures from the TAiL using pitch as the attended stimulus feature. The second and fourth components were labeled as “spatial orienting” and “spatial conflict,” respectively—they were comprised of orienting and conflict resolution measures from the vANT, aANT, and TAiL attend-location task—all tasks based upon spatial judgments (e.g., the direction of a target arrow or sound location).Conclusions: These results do not support our a-priori hypothesis that attention networks are either modality specific or supramodal. Auditory attention separated into selectively attending to spatial and non-spatial features, with the auditory spatial attention loading onto the same factor as visual spatial attention, suggesting spatial attention is supramodal. However, since our study did not include a non-spatial measure of visual attention, further research will be required to ascertain whether non-spatial attention is modality-specific.

Sex-related differences in task switching: An fMRI study

Executive functions are the important human ability to program, regulate, and control the implementation of various cognitive processes, such as voluntary task switching. However, sex-related features of this process have not been characterized in sufficient detail. These distinctive features were studied using functional magnetic resonance imaging (fMRI) and neuropsychological examination. Seventy healthy subjects 21–48 years of age (36 men and 34 women) were involved in the study. During an fMRI experiment, the subjects had to shift their attention between two tasks (classifying figures according to their form or number). In neuropsychological examination participants completed a series of visual attention, task switching, and memory tests. The fMRI study revealed that a neuronal network controlling task switching in women includes the dorsolateral prefrontal and inferior parietal cortical areas, as well as the secondary areas of the visual cortex in the left hemisphere (LH) and the right hemisphere (RH), and cortical areas of the left and right hemispheres of the cerebellum. The same areas were activated in men and additional sites of activation were detected in the supplementary motor area, right insula, and left thalamus. Comparison of the groups of men and women revealed significantly stronger activation of the prefrontal areas in both LH and RH, the left parietal lobe, and the right insula in men, and moreover activation of the supplementary motor area was observed in men but not in women. Neuropsychological testing showed that men took significantly more time to perform tasks requiring task switching, searching for stimuli, and arranging them. The data obtained indicate differences in the organization of visual task switching processes in men and women.

Visual Attention in Children With Migraine: The Importance of Prophylaxis.

This study aimed to compare the visual attention performance of children newly diagnosed with migraine, children undergoing migraine prophylaxis, and a healthy control group. Eighty-two children aged 8 to 12 years were divided into 3 groups: untreated migraine (n = 30), migraine prophylaxis (n = 22), and control (n = 30). All were subjected to a visual attention assessment with the Trail Making Test parts A and B, Letter-Cancellation Test, and the Brazilian Visual Attention Test 3rd edition. Although performance in attention tasks was within the normal range in all groups, children with untreated migraine performed significantly worse in some visual attention tests than did the control children or children undergoing migraine prophylaxis. The migraine prophylaxis group performed as well as the control group. The deregulation of the neurochemical mechanisms underlying the physiopathology of migraine might induce visual attention deficits, but an effective prophylactic treatment might reverse migraine symptoms.

295 Cognition in adult patients with cystic fibrosis (CF) with and without cystic fibrosis related diabetes (CFRD)

Objectives Impaired glucose tolerance (IGT), type 1 (T1DM) and type 2 diabetes mellitus (T2DM) have deleterious effects on cognitive performance. Hence, patients with cystic fibrosis related diabetes (CFRD) are hypothesized to show similar impairment. This study aimed to elucidate the nature and severity of any cognitive impairment in patients with CFRD compared to non-diabetic patients with CF and healthy controls matched as closely as possible for age, gender and education level. Patients with CF were also matched as closely as possible on CFTR genotype. Methods Adult (>16 years old), pancreatic insufficient patients registered to the Leeds CF Unit who had adequate verbal and written English were eligible. To date, 45 patients with insulin-treated CFRD and 47 non-diabetics who had received a normal oral glucose tolerance test (OGTT) within the past 12 months were included. 10 healthy controls were recruited to date from relatives of patients and the general population. Cognitive performance was assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB). Results Preliminary findings show that matched controls perform better than both groups of patients with CF on tests of visual memory and learning, verbal memory, visual sustained attention and executive function. Patients with CFRD performed worse than controls on tests of mental flexibility and visual sustained attention, which is consistent with the pattern of impairment shown in T1DM, and on verbal memory, which is consistent with the pattern of impairment shown in T2DM. Conclusion Like T1DM and T2DM, CFRD may have a negative impact on cognitive performance and needs to be explored.

Cognitive phenotype of psychotic symptoms in Alzheimer's disease: evidence for impaired visuoperceptual function in the misidentification subtype.

BackgroundEstablishing the cognitive phenotype of psychotic symptoms in Alzheimer's disease (AD) could localise discrete pathology and target symptomatic treatment. This study aimed to establish whether psychotic symptoms would be associated with poorer performance on neuropsychological tests known to correlate with striatal dopaminergic function and to investigate whether these differences would be attributed to the paranoid (persecutory delusions) or misidentification (misidentification phenomena +/− hallucinations) subtype.MethodsSeventy patients with probable AD (34 psychotic and 36 nonpsychotic) were recruited to the study. Analysis of covariance was used to compare motor speed and the rapid visual processing test of sustained visual attention, after adjusting for potential confounding factors. Multivariate analyses were used to compare performance across other cognitive domains. Significant findings were explored by separating patients on the basis of subtype.ResultsRapid visual processing performance accuracy was reduced in patients with psychotic symptoms (F 1,58 = 5.94, p = 0.02) and differed significantly across subtypes (F 2,51 = 3.94, p = 0.03), largely because of poorer performance in the misidentification compared with nonpsychotic group. Multivariate analyses (corrected for multiple comparisons) showed poorer performance on the incomplete letters task in psychotic patients (F 1,63 = 8.77, p = 0.004) and across subtypes (F 2,55 = 10.90, p < 0.001), similarly attributed to the misidentification subtype.ConclusionsThese findings provide further support of the involvement of dopaminergic networks in the psychosis endophenotype in AD and, in addition, implicate the ventral (temporo‐occipital) pathway in the misidentification subtype. Future studies should investigate the early trajectory of neuropathological change in vivo across psychosis subtypes.© 2015 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd.

Psychopathology and cognitive performance in individuals with membrane-associated guanylate kinase mutations: a functional network phenotyping study.

BackgroundRare pathogenic variants in membrane-associated guanylate kinase (MAGUK) genes cause intellectual disability (ID) and have recently been associated with neuropsychiatric risk in the non-ID population. However, it is not known whether risk for psychiatric symptoms amongst individuals with ID due to MAGUK gene mutations is higher than expected for the degree of general intellectual impairment, nor whether specific cognitive differences are associated with disruption to this gene functional network.MethodsThis study addresses these two questions via behavioural questionnaires and cognitive testing, applying quantitative methods previously validated in populations with ID. We compared males with X-linked ID caused by mutations in three MAGUK genes (PAK3, DLG3, OPHN1; n = 9) to males with ID caused by mutations in other X chromosome genes (n = 17). Non-parametric and parametric analyses were applied as appropriate to data.ResultsGroups did not differ in age, global cognitive impairment, adaptive function or epilepsy prevalence. However, individuals with MAGUK gene mutations demonstrated significantly higher psychopathology risks, comprising elevated total problem behaviours, prominent hyperactivity and elevated scores on an autism screening checklist. Despite these overt difficulties, individuals in the MAGUK group performed more accurately than expected for age and intelligence quotient (IQ) on computerised tests of visual attention, convergent with mouse models of MAGUK loss-of-function.ConclusionsOur findings support a role for MAGUK genes in influencing cognitive parameters relevant to psychiatric risk. In addition to establishing clear patterns of impairment for this group, our findings highlight the importance of careful phenotyping after genetic diagnosis, showing that gene functional network disruptions can be associated with specific psychopathological risks and cognitive differences within the context of ID.Electronic supplementary materialThe online version of this article (doi:10.1186/s11689-015-9105-x) contains supplementary material, which is available to authorized users.

Methods to test visual attention online.

Online data collection methods have particular appeal to behavioral scientists because they offer the promise of much larger and much more representative data samples than can typically be collected on college campuses. However, before such methods can be widely adopted, a number of technological challenges must be overcome--in particular in experiments where tight control over stimulus properties is necessary. Here we present methods for collecting performance data on two tests of visual attention. Both tests require control over the visual angle of the stimuli (which in turn requires knowledge of the viewing distance, monitor size, screen resolution, etc.) and the timing of the stimuli (as the tests involve either briefly flashed stimuli or stimuli that move at specific rates). Data collected on these tests from over 1,700 online participants were consistent with data collected in laboratory-based versions of the exact same tests. These results suggest that with proper care, timing/stimulus size dependent tasks can be deployed in web-based settings.

Generalization of sensory auditory learning to top-down skills in a randomized controlled trial.

Research has shown that auditory training improves auditory sensory skills; however, it is unclear whether this improvement is transferred to top-down skills, such as memory, attention, and language, and whether it depends on group characteristics in regard to memory and attention skills. The primary goal of this research was to investigate the generalization of learning from auditory sensory skills to top-down skills such as memory, attention, and language. We also aimed to compare whether this generalization process occurs in the same way among typically developing children and children with speech sound disorder. This study was a randomized controlled trial. Typically developing 7- to 12-yr-old children and children with speech sound disorder were separated into four groups: a trained control group (TDT; n = 10, age 9.6 ± 2.0 yr), a nontrained control group (TDNT; n = 11, age 8.2 ± 1.6 yr), a trained study group (SSDT; n = 10, age 7.7 ± 1.2 yr), and a nontrained study group (SSDNT; n = 8, age 8.6 ± 1.2 yr). Both trained groups underwent a computerized, nonverbal auditory training that focused on frequency discrimination, ordering, and backward-masking tasks. The training consisted of twelve 45 min sessions, once a week, for a total of 9 hr of training, approximately. Near-transfer (Gap-In-Noise [GIN] and Frequency Pattern Test) and far-transfer measures (auditory and visual sustained attention tests, phonological working memory and language tests) were applied before and after training. The results were analyzed using a 2 × 2 × 2 mixed-model analysis of variance with the group and training as the between-group variables and the period as the within-group variable. The significance threshold was p ≤ 0.05. There was a group × period × training interaction for GIN [F(1.35) = 7.18, p = 0.011], indicating a significant threshold reduction only for the TDT group (Tukey multiple comparisons). There was a significant group × period interaction [F(1.35) = 5.52, p = 0.025] and a training × period interaction for visual reaction time [F(1.35) = 4.20, p = 0.048], indicating improvement in the SSDT group and worsening in both nontrained groups. There was also a significant group × training × period interaction [F(1.35) = 4.27, p = 0.046] for the auditory false alarms, with a significant improvement after training only for the SSDT group. Analysis of variance also revealed that all groups exhibited approximately the same level of gains for all measures, except for GIN [F(3,38) = 4.261, p = 0.011] and visual response time [F(3.38) = 4.069, p = 0.014]. After training, the TDT group demonstrated a significant improvement for GIN and the SSDT exhibited the same for sustained attention, indicating learning generalization from an auditory sensory training to a top-down skill. For the other measures, all groups exhibited approximately the same level of gains, indicating the presence of a test-retest effect. Our findings also show that the memory span was not related to the learning generalization process given that the SSDT exhibited a more pronounced gain in attention skills after the sensory training.

Noise exposure and cognitive performance: A study on personnel on board Royal Norwegian Navy vessels.

Prior research shows that work on board vessels of the Royal Norwegian Navy (RNoN) is associated with noise exposure levels above recommended standards. Further, noise exposure has been found to impair cognitive performance in environmental, occupational, and experimental settings, although prior research in naval and maritime settings is sparse. The aim of this study was to evaluate cognitive performance after exposure to noise among personnel working on board vessels in the RNoN. Altogether 87 Navy personnel (80 men, 7 women; 31 ± 9 years) from 24 RNoN vessels were included. Noise exposure was recorded by personal noise dosimeters at a minimum of 4 h prior to testing, and categorized into 4 groups for the analysis: <72.6 dB(A), 72.6-77.0 dB(A), 77.1-85.2 dB(A), and >85.2 dB(A). The participants performed a visual attention test based on the Posner cue-target paradigm. Multivariable general linear model (GLM) analyses were performed to analyze whether noise exposure was associated with response time (RT) when adjusting for the covariates age, alertness, workload, noise exposure in test location, sleep the night before testing, use of hearing protection device (HPD), and percentage of errors. When adjusting for covariates, RT was significantly increased among personnel exposed to >85.2 dB(A) and 77.1-85.2 dB(A) compared to personnel exposed to <72.6 dB(A).

Objective assessment of visual attention in mild traumatic brain injury (mTBI) using visual-evoked potentials (VEP)

Purpose: To quantify visual attention objectively using the visual-evoked potential (VEP) in those having mild traumatic brain injury (mTBI) with and without a self-reported attentional deficit.Research design and methods: Subjects were comprised of 16 adults with mTBI: 11 with an attentional deficit and five without. Three test conditions were used to assess the visual attentional state to quantify objectively the VEP alpha band attenuation ratio (AR) related to attention: (1) pattern VEP; (2) eyes-closed; and (3) eyes-closed number counting. The AR was calculated for both the individual and combined alpha frequencies (8–13 Hz). The objective results were compared to two subjective tests of visual and general attention (i.e. the VSAT and ASRS, respectively).Results: The AR for both the individual and combined alpha frequencies was found to be abnormal in those with mTBI having an attentional deficit. In contrast, the AR was normal in those with mTBI but without an attentional deficit. The AR correlated with the ASRS, but not with the VSAT, test scores.Conclusions: The objective and subjective tests were able to differentiate between those having mTBI with and without an attentional deficit. The proposed VEP protocol can be used in the clinic to detect and assess objectively and reliably a visual attentional deficit in the mTBI population.

P-63 * AEROBIC KICKBOXING TRAINING FOR SUBSTANCE ABUSE REHABILITATION IN HONG KONG

Introduction. Evidence had proven the positive effect of exercise therapy for illicit drug abusers. However, the effectiveness of exercise for ketamine abusers, who were dominant in Hong Kong, was unknown. Objective. To evaluate the effect of structured exercise program for health and relapse prevention for rehabilitees in Drug Treatment and Rehabilitation Centers (DTRCs) in Hong Kong. Methodology. Following the baseline assessments on physical fitness, mental health, cognitive function and relapse risk, all subjects received an 8-week aerobic kickboxing training followed by post-exercise reassessment. Results. From September to December 2013, 23 female subjects with mean age of 22.8 years (SD 3.0) were recruited. Among all subjects, 74% with drug abused for 5 years or more. Poly-substance abusers accounted for 91.3%; in which 78.3% were ketamine abusers. For baseline assessment, the risk of central obesity increased by 34.6% for subjects admitted to DTRCs for more than 3 months (p = 0.110). For the post-exercise evaluation, significant improvements were reported on waist circumference (29.6 to 28.5 inches; p = 0.000), peak flow rate (340 to 380 L/min; p = 0.001), sit-up (17 to 22 repetitions; p = 0.000), sit-and-reach (31 to 37 cm; p = 0.001), hexagon jump test (26.0 to 20.8 sec; p = 0.000) and agility ladder test (p = 0.000). The cardiovascular fitness was improved from 40.6ml/kg/min to 42.3ml/kg/min (p = 0.073) after training. For mental health, 30.4% of the subjects showed moderate to severe depression in Beck Depression Inventory (BDI) and 21.7% showed anxiety disorder in Hospital Anxiety and Depression Scale- Anxiety subscale (HADs-Anx). BDI significantly reduced from 14.3 to 10.5 (p = 0.046) and HADS-Anx reduced from 8.3 to 6.1 (p = 0.101) after training. For cognitive function assessed by CANTAB tests, 78.3% and 64.3% of the subjects failed episodic visual memory and visual sustained attention tests respectively. Significant improvement in visual memory (p = 0.018) and an overall improvement in spatial planning (p = 0.202), rule acquisition and attentional set shifting (p = 0.147) were revealed. For relapse prevention, significant improvements in Stimulant Relapse Risk Scale (64.4 to 56.2; p = 0.01) and contemplation stage (7.8 to 8.3; p = 0.001) were found. Conclusion. Exercise therapy was shown to have a merit for substance abuse rehabilitation, including ketamine abusers.