Divided Attention Test Research Articles

Divided visual attention as a predictor of bumping while walking: the Salisbury Eye Evaluation.

The purpose of this study was to determine the association between bumping while walking and divided visual attention, as measured by the useful field of view (UFOV). The Salisbury Eye Evaluation is a population-based study of community-dwelling adults, aged 72 to 92 at the third round of data collection. Participants walked a circuitous 32.8-m course, seeded with obstacles, and the number of bumps made while traversing the course was counted. UFOV divided attention score was based on processing speed: the time taken to identify a central target, and the location of a peripheral target simultaneously. Association between number of bumps and UFOV score was assessed in a generalized linear model, with adjustment for vision and attention measures that might explain the UFOV score. Of the 1504 participants in this study, 10.1% did not attempt the mobility course. In a model adjusting for demographic, physical, cognitive and attention, and vision measures, a decrease of 50 ms in processing speed for the divided-attention task was associated with a 4.9% increase (P = 0.004) in number of bumps made over the course. Receiver operating characteristic curves were created for the UFOV and visual field tests, to determine accuracy in detecting those with a high number of bumps. The visual field test had slightly higher area under the curve, but positive predictive value for both tests was low. The UFOV test of divided attention, as measured by processing speed, independently predicted bumping while walking. These data suggest that poor visual attention is a significant risk factor for bumping while walking.

Preliminary evidence of hippocampal dysfunction in adolescent MDMA ("ecstasy") users: possible relationship to neurotoxic effects.

3,4-Methylenedioxymethamphetamine (MDMA or ecstasy) is a potent and selective serotonin neurotoxin whose use is growing among adolescents. Although cognitive deficits among adult MDMA users are well documented, little is known of the cognitive and brain functional sequelae of MDMA use during adolescence. We tested for evidence of cognitive deficits and changes in brain function in a pilot sample of adolescent MDMA users, who were compared with adolescent non-users of MDMA. Selective and divided attention and verbal working memory were examined in six adolescent MDMA users and six non-users of MDMA who were similar in age, gender, IQ, and other substance use. Brain function was assessed during performance of the working memory task using functional magnetic resonance imaging (fMRI). MDMA users had significantly prolonged reaction times during tests of selective and divided attention, and failed to deactivate the left hippocampus normally during high verbal working memory load. MDMA use in adolescence may be associated with cognitive impairments and dysfunction of inhibitory circuits within the hippocampus. Further work is urgently needed to delineate the developmental impact and long-term functional and clinical significance of MDMA use during adolescence.

Functional Disconnection of the Medial Prefrontal Cortex and Subthalamic Nucleus in Attentional Performance: Evidence for Corticosubthalamic Interaction

The present study used a disconnection procedure to test whether the medial prefrontal cortex (mPFC) and the subthalamic nucleus (STN) were functional components in a common neural system that controlled continuous performance in a test of sustained and divided visual attention. Animals with disconnected lesions of the mPFC and STN in contralateral hemispheres were severely impaired in several aspects of performance, including discriminative accuracy, increased perseveration, and slowed response latencies during postoperative testing. These deficits persisted throughout the entire experimental test period. Increasing the stimulus duration alleviated the accuracy deficit but failed to improve speed of responding or reduce perseverative responses. These deficits were in marked contrast to animals with combined mPFC and STN lesions made on the ipsilateral side, which produced behavior not different from that of sham controls. Rats with unilateral lesions of either structure alone were also impaired in terms of accuracy and perseveration. These data suggest that some of the deficits observed after bilateral STN lesions (attention and perseveration) may be attributable to a disrupted corticosubthalamic projection. This study provides direct evidence that performance in tasks that require optimal attentional and executive control relies on a corticosubthalamic interaction within the neural circuitry of the basal ganglia.

Impaired and enhanced attentional function in children with attention deficit/hyperactivity disorder.

The symptom domain of inattention in attention deficit/hyperactivity disorder (ADHD) suggests that there are neuropsychological fields of attention in which subjects with ADHD express deficits. However, studies using differentiated neuropsychological attentional tests in ADHD are lacking. A consecutive series of 35 subjects with ADHD aged 9-12 years were assessed on a computer-driven neuropsychological test battery for attentional functions. Their performance was classified according to the data of a normative sample of 187 healthy subjects aged 9-12 years, and compared with the performance of 35 matched healthy control subjects. According to normative data, most ADHD subjects performed on all attentional measures within the normal range. Comparisons with the control group revealed that ADHD subjects reacted faster on all attentional tests, yielding statistical significance for the Go/No go test and the Divided Attention test. They also performed with significantly fewer errors on the Divided Attention test. On the Go/No go test, Visual Scanning test and Attentional Shift test ADHD subjects committed significantly more errors than control subjects. Our results suggest a differential pattern rather than a deficit pattern of attentional functions in ADHD. It is suggested that the more rapid response style of ADHD subjects leads to a more erroneous performance in self-paced attentional tasks and to a better performance in externally paced attentional tasks. However, neuropsychological tests of attention do not contribute to the clinical diagnosis of ADHD.

Prefrontal cortical dysfunction and genetic polymorphisms of the COMT gene in subjects with schizophrenia: A genetic study of a schizophrenia endophenotype

Schizophrenia is associated with impairments in many cognitive domains on which the influence of antipsychotics, whether conventional or atypical, remains unclear. We conducted a study of recent-onset schizophrenic patients (DSM IV) that included unmedicated (n = 19), and medicated (n = 19) patients matched for age and IQ. Both groups of patients had comparably low extra-pyramidal symptoms (EPS). Cognitive tasks included attentional tasks (alertness and divided attention tests), a working memory task (a verbal n-back test) and the Wisconsin Card Sorting Test (WCST). After adjustment for the Total PANSS score, we found no significant difference between the two groups of patients in any of the cognitive tasks. When compared to a group of healthy controls (n = 20) matched for IQ level, unmedicated patients performed significantly worse in all cognitive tasks, with significantly longer reaction times for alertness, divided attention and working memory.These results confirm the presence of cognitive impairments in attentional and executive functions in recent-onset patients whether or not they are medicated. There was no evidence that either conventional or atypical antipsychotics had an influence on patients when EPS were excluded. Altogether, our results further support the idea that cognitive deficits in schizophrenia are enduring features per se and cannot be considered as secondary to psychiatric symptoms or to the adverse effects of medication. In addition our results suggest that antipsychotics do not have a major effect on these impairments.

Acute and subchronic effects of levocetirizine and diphenhydramine on memory functioning, psychomotor performance, and mood

Background: Central nervous system adverse effects, such as sedation, often accompany the use of first-generation antihistamines. These effects might interfere with memory functioning and psychomotor performance. Levocetirizine was recently introduced as a new antihistamine said to be free from sedative effects. Objective: We sought to investigate the effects of levocetirizine (5 mg), diphenhydramine (50 mg), and placebo on memory and psychomotor performance after acute (day 1) and subchronic (day 4) daily administration in 48 healthy volunteers (24 men and 24 women). Methods: This study was a double-blind, placebo-controlled, randomized clinical trial. Treatments were administrated on days 1, 2, 3, and 4, 3 hours before the start of the laboratory test battery (performed on days 1 and 4), comprising a word-learning test, the Sternberg Memory Scanning Test, a tracking test (easy and hard version), and a divided attention test (tracking and memory scanning simultaneously). Statistical analyses were performed separately for days 1 and 4 by using analysis of variance. Results: On day 1, diphenhydramine significantly impaired tracking performance (easy: F1,90 = 25.9, P < .0001; hard: F1,90 = 20.5, P < .0001) and divided attention (tracking: F1,90 = 23.8, P < .0001; memory scanning: F1,90 = 22.0, P < .0001). Results on word-learning tests and Sternberg Memory Scanning Tests were not significantly impaired. On day 4, the effects of diphenhydramine did not reach significance. In contrast, on both days 1 and 4, levocetirizine did not significantly impair laboratory test performance. Conclusion: The results show that memory, attention, and tracking performance are unaffected after acute and subchronic administration of levocetirizine (5 mg), whereas diphenhydramine (50 mg) significantly affected divided attention and tracking after acute administration. (J Allergy Clin Immunol 2003;111:623-7.)

Sex-related differences in spatial divided attention and motor impulsivity in rats.

The acquisition and performance of a self-paced test of spatial divided attention linked with frontal cortex function were assessed in postpubertal (> 60 days) normal or gonadectomized male and female rats. Males were more accurate at detecting relatively brief visual stimuli than females, but this difference was eliminated by increasing the target stimulus duration, indicating an attentional basis for this effect. Premature errors were, however, greater in males than in females, suggesting greater impulsivity in males. Subsequent experiments in gonadectomized rats suggest that circulating hormones influence attention and impulsivity, but not necessarily sex differences. These results demonstrate a double dissociation between components of impulse control and divided attention in male and female rats and may have implications for sex differences in disorders of attention and cognition.

Residual Effects of Middle-of-the-Night Administration of Zaleplon and Zolpidem on Driving Ability, Memory Functions, and Psychomotor Performance

Thirty healthy volunteers participated in this two-part study. Part 1 was a single-blind, two-period crossover design to determine the effects of a single dose of ethanol (0.03% < BAC < 0.05%) or ethanol-placebo on driving ability, memory, and psychomotor performance. Part 2 was a double-blind, five-period crossover design to measure the effects of a middle-of-the-night administration of zaleplon 10 or 20 mg, zolpidem 10 or 20 mg, or placebo on driving ability 4 hours after administration and memory and psychomotor performance 6 hours after administration. The on-the-road driving test consisted of operating an instrumented automobile over a 100-km highway circuit at a constant speed (95 km/h) while maintaining a steady lateral position between the right lane boundaries. The standard deviation of lateral position (SDLP) was the primary performance parameter of the driving test. The psychomotor and memory test battery consisted of the Word Learning Test, the Critical Tracking Test, the Divided Attention Test, and the Digit Symbol Substitution Test. Data for each part were analyzed separately using ANOVA for crossover designs. Zaleplon 10 and 20 mg did not significantly impair driving ability 4 hours after middle-of-the-night administration. Relative to placebo, after zolpidem 10 mg, SDLP was significantly elevated, but the magnitude of the difference was small and not likely to be of clinical importance. Memory and psychomotor test performance was unaffected after both doses of zaleplon and zolpidem 10 mg. In contrast, zolpidem 20 mg significantly increased SDLP and speed variability. Further, zolpidem 20 mg significantly impaired performance on all psychomotor and memory tests. Finally, driving performance, Digit Symbol Substitution Test, Divided Attention Test, and immediate and delayed free recall of the Word Learning Test were significantly impaired after ethanol. The results show that zaleplon (10 and 20 mg) is a safe hypnotic devoid of next-morning residual impairment when used in the middle of the night.

Attention Deficits in Patients with Persisting Postconcussive Complaints: A General Deficit or Specific Component Deficit?

This study aimed to examine attentional performance in patients with persisting postconcussive complaints, using a multi-componential perspective. Comparisons of attentional performances of 92 patients with postconcussive complaints and 86 normal controls were conducted using tests of sustained attention (Sustained Attention to Response Task; Digit Backward Span), selective attention (Stroop Word-Color Test; Color Trails Test), divided attention (Paced Auditory Serial Addition Test; Symbol Digit Modalities Test), and attentional control processing (Six Elements Test; Tower of Hanoi). Questionnaires on daily life inattentive behaviour were also administered to all participants and their significant others. A MANOVA indicated that patients with persisting postconcussive complaints demonstrated a general deficit in attentional performance as compared with their normal controls, F (18, 145) = 7.939, p = .005. These patterns still persisted when measures of emotional disturbance were controlled, F (18, 143) = 5.159, p = .005. Moreover, for sustained attention and selective attention, we were able to statistically control for speed and the differences remained. Future research should be conducted to better control the potential confound of speed for all the attentional components in order to differentiate any specific component deficits in these patients.

Effects of Alprazolam on Driving Ability, Memory Functioning and Psychomotor Performance: A Randomized, Placebo-controlled Study

Alprazolam is prescribed for the treatment of anxiety and panic disorder. Most users are presumably involved in daily activities such as driving. However, the effects of alprazolam on driving ability have never been investigated. This study was conducted to determine the effects of alprazolam (1 mg) on driving ability, memory and psychomotor performance. Twenty healthy volunteers participated in a randomized, double-blind, placebo-controlled crossover study. One hour after oral administration, subjects performed a standardized driving test on a primary highway during normal traffic. They were instructed to drive with a constant speed (90 km/h) while maintaining a steady lateral position within the right traffic lane. Primary performance measures were the Standard Deviation of Lateral Position (SDLP) and the Standard Deviation of Speed (SDS). After the driving test, subjective driving quality, mental effort, and mental activation during driving were assessed. A laboratory test battery was performed 2.5 h after treatment administration, comprising the Sternberg Memory Scanning Test, a Continuous Tracking Test, and a Divided Attention Test. Relative to placebo, alprazolam caused serious driving impairment, as expressed by a significantly increased SDLP (F1,19 = 97.3, p < .0001) and SDS (F1,19 = 30.4, p < .0001). This was confirmed by subjective assessments showing significantly impaired driving quality (F1,19 = 16.4, p < .001), decreased alertness (F1,19 = 43.4, p < .0001), decreased mental activation (F1,19 = 5.7, p < .03) and increased mental effort during driving (F1,19 = 26.4, p < .0001). Furthermore, alprazolam significantly impaired performance on the laboratory tests. In conclusion, alprazolam users must be warned not to drive an automobile or operate potentially dangerous machinery.

Short-Term Cognitive Improvement in Schizophrenics Treated with Typical and Atypical Neuroleptics

Objective: Atypical neuroleptics seem to be more beneficial than typical ones with respect to long-term neuropsychological functioning. Thus, most studies focus on the long-term effects of neuroleptics. We were interested in whether atypical neuroleptic treatment is also superior to typical drugs over relatively short periods of time. Methods: We studied 20 schizophrenic patients [10 males, mean age 35.5 years, mean Brief Psychiatric Rating Scale (BPRS) score at entry 58.9] admitted to our hospital with acute psychotic exacerbation. Nine of them were treated with typical and 11 with atypical neuroleptics. In addition, 14 healthy drug-free subjects (6 males, mean age 31.2 years) were enrolled in the study and compared to the patients. As neuropsychological tools, a divided attention test, the Vienna reaction time test, the Benton visual retention test, digit span and a Multiple Choice Word Fluency Test (MWT-B) were used during the first week after admission, within the third week and before discharge (approximately 3 months). Results: Patients scored significantly worse than healthy controls on nearly all tests (except Vienna reaction time). Clinical ratings [BPRS and Positive and Negative Symptom Scale for Schizophrenia (PANSS)] improved markedly (p < 0.01), without a significant difference between typical and atypical medication. Clinical improvement (PANSS total score) correlated with less mistakes on the Benton test (r = 0.762, p = 0.017) and an improvement on the divided attention task (r = 0.705, p = 0.034). Neuropsychological functioning (explicit memory, p < 0.01; divided attention, p < 0.05) moderately improved for both groups under treatment but without a significant difference between atypical and typical antipsychotic drugs. Conclusions: Over short periods of time (3 months), neuropsychological disturbances in schizophrenia seem to be moderately responsive to both typical and atypical neuroleptics.

Differential Residual Effects of Zaleplon and Zopiclone on Actual Driving: a Comparison with a Low Dose of Alcohol

To compare residual effects of zaleplon 10 mg, zopiclone 7.5 mg, and placebo, and a social dose of alcohol on car driving, memory, and psychomotor performance. Two-part placebo controlled, crossover study. Part 1 was single blind, Part 2 double blind. University research institute. Thirty healthy volunteers (15 men and 15 women, mean age 32 +/- 7 years) In Part 1 alcohol and alcohol-placebo drinks were administered around noon. In Part 2 single oral doses of zaleplon 10 mg, zopiclone 7.5 mg and placebo were administered at bedtime. A highway driving test, laboratory tests of word learning, critical tracking and divided attention, and subjective assessments of sleep, mood, and effects of treatments on driving. Driving started 40 minutes after a second alcohol dose in Part 1, and 10 hours after drug intake in Part 2. The results demonstrated that alcohol, at average plasma concentrations of approximately 0.030 g/dl, significantly impaired performance in all tests. Zaleplon's residual effects did not differ significantly from those of placebo in any test. In contrast, zopiclone had significant residual effects on driving, divided attention, and memory. The magnitude of impairment in the driving test observed the morning after zopiclone 7.5 mg was twice that observed with alcohol. Zaleplon 10 mg has no residual effects on driving when taken at bedtime, 10 hours before driving. In contrast, zopiclone 7.5 mg can cause marked residual impairment. Patients should be advised to avoid driving the morning after zopiclone administration.

Effectiveness of an attention- and memory-training program on neuropsychological deficits in schizophrenia.

The effect of two cognitive remediation procedures developed for closed head injury, Attention Process Training (APT) and Prospective Memory Training (PROMT), on neuropsychological deficits in schizophrenia was investigated. Six patients with schizophrenia, varying in baseline intellectual function and symptoms, were studied; three in a remediation condition and three in a nonremediated control condition. Results were evaluated individually for each of the three treated patients. Two of three remediation-treated subjects showed marked improvement on tests of sustained and divided attention. Untreated patients showed little evidence of change in neuropsychological test performance across a similar time interval, when tested on a subset of the measures administered to remediation-treated patients. The results of this study are discussed with a view toward future studies using larger sample sizes with homogeneous subject populations.

Effects of guanfacine on three forms of distraction in the aging macaque

α-2 adrenoceptor agonists, such as clonidine and guanfacine, enhance attention in aged animals. According to one theory, α-2 receptor agonists improve attention by decreasing distractibility to task-irrelevant stimuli. In two healthy aging bonnet macaques, we investigated the effects of low- (0.001 mg/kg) and high-dose (0.05 mg/kg) acute intramuscular guanfacine versus saline control on accuracy (number of trials correct) in three tasks requiring attention: delayed matching-to-sample, one-target visual tracking (test of focused attention) and two-target visual tracking (test of divided attention). Each task employed distracting stimuli in a different paradigmatic context. One monkey responded to guanfacine at both doses with significant rises in accuracy on all three tasks. The second monkey showed significant accuracy improvement for high-dose guanfacine only. No sedation was observed. These results suggest that guanfacine improves attention and reduces distractibility in multiple task contexts in healthy aging primates.

The effects of antihistamines on cognition and performance

Allergic diseases are responsible for substantially more disability than is generally realized. Allergic rhinitis alone results in 3.5 million lost workdays and 2 million missed school days in the United States each year. Comorbid conditions such as asthma and sinusitis can be disabling as well, resulting each year in more than 10 million missed school days and more than 73 million days of restricted activity, respectively. Antihistamines continue to be the mainstay of treatment for allergic disorders. In the case of the first-generation antihistamines, however, the treatment may well be worse than the disease. Although these agents are effective H1-receptor antagonists, they are also highly lipophilic and readily cross the blood-brain barrier, causing considerable sedation. The second-generation agents are more lipophobic and possess different ionic charges than the first-generation antihistamines. As a result, they are far less likely to cross the blood-brain barrier and, for that reason, cause little if any sedation. In a recent comparative trial, subjects who were treated with the first-generation agent diphenhydramine were found to have significant performance deficits on tests of divided attention, working memory, vigilance, and speed. By contrast, subjects who were treated with the second-generation antihistamine loratadine performed as well as subjects who were treated with placebo. The sedative effects of the first-generation agents persist well into the next day and thus can potentially interfere with daytime performance and safety even when taken the night before. It is therefore recommended that patients whose occupations require vigilance, divided attention, or concentration receive only second-generation antihistamines. (J Allergy Clin Immunol 2000;105:S622-7.)

Reversible neuropsychological deficits after mild traumatic brain injury

OBJECTIVESTo determine the influence of motivation on performance in a divided attention test of patients after mild traumatic brain injury (MBI).METHODSComparison of the performance of 12 patients with MBI with...

Glucose enhances long-term declarative memory in mildly head-injured varsity rugby players

In the present investigation, we sought to determine whether glucose could enhance declarative memory in head-injured individuals, as has been shown previously with elderly and Alzheimer’s patients who had preexisting memory impairments. Varsity rugby players, both with and without a history of concussions, were given glucose- or saccharin-sweetened beverages and then tested on a series of neuropsychological tests of attention and memory; their blood-glucose levels were monitored. Beverages and tests were administered in a counterbalanced, crossover design, enabling within-subjects comparisons. Previously concussed participants were found to perform slightly worse than participants with no history of concussions (controls) on the preliminary screening interview tests and tests of memory and divided attention given in the saccharin (placebo) condition. Glucose was shown to enhance performance of the previously concussed participants and impair the performance of controls on tests of long-term declarative memory. The effects of glucose on memory appeared to be related to the participants’ ability to clear glucose from the blood.

Abstracts of literature

Abstracts of literature

Prediction of Driving Performance Through Computerized Testing: High-Risk-Driver Assessment and Training

Two 10-min computerized cognitive tests were administered to a class of 35 male North Carolina Highway Patrol cadets at the beginning of driver training. The test (performance on-line) measured scanning and divided-attention skills, including indexes of visual and cognitive tunnel vision. Five months later the cadets were given 2 weeks of intensive driver training on the track in precision cone maneuvers and skid control and a final exam in high-speed pursuit. Relationships were examined between cognitive test scores and the track ratings of experienced driving instructors. The results showed that divided-attention deficits indicating tunnel vision predicted the lack of cadets’ skills on the track final exam in high-speed pursuit. When the top and bottom 25th percentile of the cadets’ high-speed pursuit scores were used as the criteria, the differences between the groups for divided-attention responses to displays at the center of a 38-cm (15-in.) computer monitor were not significant. However, the differences between the groups were significant for divided-attention responses at the outer edges of the display, indicating cognitive tunnel vision for the lower 25 percent of drivers. Thus, the more difficult divided-attention test requirements were more likely to select good drivers on complex driving skills. In addition, the cadets who had an advantage in decision-making skills continued to improve on that advantage as training continued. The first two cadets to crash on the road in the first year after training were in the bottom 15th percentile for divided-attention test scores. Implications for driver assessment and training are discussed.

Differing Patterns of Cognitive Dysfunction and Heart Rate Reactivity in Chemically-Intolerant Individuals With and Without Lifestyle Changes

AbstractThe purpose of the present study was to compare specific neuropsychological, psychological, and family history patterns, as well as cardiovascular reactivity of three community-recruited groups of nonsmoking, nonalcoholic middle-aged individuals with and without the symptom of intolerance to low levels of environmental chemicals (CI). CI is a common symptom in chronic fatigue syndrome and fibro-myalgia. The groups included: (i) CI who had made associated lifestyle changes because of the CI (CI/LSC); (ii) CI who had not made such changes (CI); and (iii) normals without CI (N). All subjects underwent an evaluation session followed by two laboratory cognitive and psycho-physiological test sessions one week apart. The CI/LSC diverged from the other groups in exhibiting poorer performance on the Continuous Visual Memory Test (CVMT) in terms of more false alarms and fewer correct hits, but normal performance on a visuospatial test of divided attention (DAT). In contrast, the CI group showed progressivel...