Divided Attention Test Research Articles

Cognitive deficits in the acute stage after subarachnoid hemorrhage.

In spite of fundamentally improved medical management of subarachnoid hemorrhage (SAH), many patients remain mentally impaired. However, the causes of these disturbances are unclear. The present study was performed to elucidate the significance of the hemorrhage itself and related events in the neuropsychological performance of patients in the acute stage after SAH. A series of 51 patients were examined, by means of a battery of cognitive tests, 1 to 13 days (mean, 5.9 d) after SAH. Thirty-three patients had experienced ruptured aneurysms, and 18 had sustained SAH of unknown origin. Furthermore, 25 patients who had undergone surgical treatment (a mean of 5.0 d earlier) of prolapsed lumbar discs served as a control group. The cognitive deficits of the patients after aneurysmal SAH proved to be comparable to those after spontaneous SAH of unknown origin, with the single exception of a significantly worse (P = 0.003) concentration capacity in the surgically treated group. The severity of SAH in computed tomographic scans correlated (up to r = 0.57, P < 0.001) with poor performance on tests of memory, concentration, divided attention, and perseveration. Frontal intracerebral hemorrhage led to significantly more errors in an aphasia screening test (P < 0.001) and a test of perseveration (P < 0.001). If acute hydrocephalus was present, the patients exhibited worse long-term memory (P < 0.001), showed slower reaction times (P = 0.01), and made more errors in the perseveration test (P = 0.004). Patients with intraventricular blood performed at significantly lower levels in the concentration (P = 0.001), divided attention (P = 0.01), long-term memory (P < 0.001), and perseveration (P = 0.003) tests. The results emphasize that the severity of SAH (Fisher score) is the most important factor related to cognitive dysfunction, but frontal hematoma, intraventricular hemorrhage, and acute hydrocephalus were also associated with cognitive deficits, compared with patients with SAH without these findings.

Are PASAT Scores Related to Mathematical Ability?

The Paced Auditory Serial Addition Task (PASAT) is employed in neuropsychological practice as a test of divided attention. The influence of mathematical ability on PASAT performance was examined in 40 healthy subjects, 20 male and 20 female. An unpaced computerised task was developed to measure response times for the verification of visually-presented additions, subtractions, divisions, and multiplications. Response times were always strongly negatively correlated with PASAT scores, suggesting that high mental arithmetic ability may give rise to good PASAT performance. Furthermore, a significant percentage of the variability in PASAT scores was predicted by (1) recent attainment in school mathematics examinations, and (2) self-ratings of current mental arithmetic skills. It is suggested that mathematical attainment and ability should be taken into account when interpreting PASAT performance as a measure of divided attention.

Bilateral lesions of the subthalamic nucleus induce multiple deficits in an attentional task in rats.

Lesioning the subthalamic nucleus (STN) has been suggested as possible therapy for the treatment of parkinsonism. Previous experiments investigating this hypothesis in rats confirmed that excitotoxic STN lesions alleviate the motor impairment induced by striatal dopamine depletion, which reproduced the degeneration observed in parkinsonism, but elicited presumed non-motor deficits such as premature responding, suggesting that the STN could be involved in other aspects of response control. The aim of the present study was to extend this analysis to choice paradigms. We thus investigated the behavioural effects of bilateral excitotoxic lesions of the STN in rats performing a five-choice test of divided and sustained visual attention, modelled on the human continuous performance task. This task required the animals to detect a brief visual stimulus presented in one of five possible locations and respond by a nose-poke in this illuminated hole within a fixed delay, for food reinforcement. Bilateral lesions of the STN severely impaired several aspects of performance, including discriminative accuracy, but also increased premature, anticipatory responding as well as perseverative panel pushes and nose-poke responses. While increasing the stimulus duration and reducing the waiting period for the stimulus partially alleviated the accuracy deficit and the premature responding deficit respectively, other deficits, such as perseverative panel pushes and nose-poke responses, were sustained under these conditions. Systemic injection of the mixed dopaminergic D1/D2 receptor antagonist, alpha-flupenthixol (0.03-0.18 mg/kg), reduced premature responses and perseverative panel pushing without affecting the perseverative nose-poke responses, suggesting that some of the deficits were independent of striatal dopaminergic transmission. These results suggest that STN lesions have multiple, dissociable effects on attentional performance, including discriminative deficits, impulsivity and perseverative behaviour. They are consistent in part with a hypothesized role of the STN in recent models of basal ganglia function in action selection and inhibition. The results also show that other aspects of behaviour should be monitored when examining the capacity of STN lesions to reverse the parkinsonian deficit induced by striatal dopamine depletion.

Side effects from increased doses of carbamazepine on neuropsychological and posturographic parameters of humans

Patients taking anticonvulsant drugs display a broad spectrum of side-effects. Particularly, in the beginning of treatment and with increasing doses of carbamazepine, side effects such as dizziness, ataxia, drowsiness and reduction of alertness occur, which improve some days after the dose has reached a stable level. Our aim was to find objective parameters for grading these side effects and to differentiate between neurophysiological and neuropsychological side effects of carbamazepine in a clinical situation. Twenty-two patients with trigeminal neuralgia were included for a follow-up study with increasing carbamazepine doses (0 mg to 600 mg). The effect of carbamazepine on postural stability was quantified by posturography. Different neuropsychological tests to study cognitive effects of carbamazepine were performed. The composite equilibrium score showed a significant reduction of postural stability with increasing doses of carbamazepine. In sensory analysis the somatosensory ratio was significantly influenced by increased doses of carbamazepine during the study. Mean reaction time of tonic alertness and phasical alertness varied significantly with different doses of carbamazepine. There was a significant influence in patients attention during trail making tests and divided attention tests with increase in carbamazepine. In conclusion our observations show that the rate of change of carbamazepine doses is an important determinant of cognitive and motor functions in the phase of increasing doses.

Acute effects of kava, alone or in combination with alcohol, on subjective measures of impairment and intoxication and on cognitive performance

Kava (Piper methysticum) and alcohol were administered either separately or in combination to human subjects. Self-reports of their levels of impairment and intoxication were collected, and performance skills on a number of cognitive and visuomotor tests were determined, before and three times after consumption of the experimental drink. Kava alone had no effect on reported condition. In contrast, alcohol produced marked changes in each of the five subjective measures, all of which were in the direction of lowered ability. The combination of these two substances produced even larger negative changes on these measures. In the cognitive tests, kava produced a decrement in performance on Digit Symbol Coding. Alcohol produced a significant decrease in performance on a divided attention test, which was almost entirely on the peripheral, discontinuous component of the test. The combination of kava and alcohol produced an even greater decrease in performance on this test, and in the same component. The present findings suggest that kava alone has little effect on reported condition and cognitive performance, but appears to potentiate both perceived and measured impairment when combined with alcohol.

The effects of glucose on nonmemory cognitive functioning in the elderly

The present study evaluated the role of glucose in the performance of a series of memory and nonmemory neuropsychological tasks. Each of the 28 healthy (no evidence of diabetic or dementing disease), elderly (mean age = 73), subjects participating in the study were tested under each of two conditions (50 g glucose or 27.3 mg saccharin) in a counterbalanced fashion. While actively manipulating glucose levels in participants, blood glucose (BG) levels were monitored to evaluate the effectiveness of individual subject's regulation of ingested glucose. It was hypothesized that glucose would enhance performance on a memory measure (Rey/Taylor Figure) as well as other nonmemory measures (e.g. design fluency, trail making test, etc.). A repeated measures, counterbalanced design was used to evaluate the direct manipulation of glycemic condition. Results reveal an enhancement effect on both the recall of the Rey/Taylor Figure as well as verbal fluency and figural fluency. A significant correlation between glycemic regulation and performance on a test of divided attention (dichotic listening) was also evident ( r = −0.47). These findings suggest that a specific facilitation of retrieval mechanisms may account for enhancement of both memory and fluency performance.

Ethanol Pharmacodynamics at Low Blood Concentrations.

Ranitidine has been shown to produce increases in blood alcohol concentration (BAC) after low doses of alcohol. The objective of this study was to reproduce, in a controlled setting, the BACs seen after low oral doses of ethanol in the presence and absence of ranitidine and to assess the effect of these concentrations on cognitive performance. An active control group (0.45 g per kg alcohol) was included as a validation of the methodology used. A randomized, double-blind, placebo-controlled, four-way crossover study was performed in eight healthy males. Subjects received a 20-min intravenous infusion of 0.10, 0.15, or 0.45 g per kg alcohol or placebo. Blood samples were obtained to measure BAC and psychometric effects were assessed over 8 h. A pharmacokinetic model was used to fit simultaneously the BAC--time profiles of all three doses for each subject. Cognitive improvement was assessed using digit symbol substitution, continuous tracking, and divided attention tests. Analysis of variance was conducted in order to compare peak blood alcohol impairment (E(max)) and area under the alcohol impairment--time curve (AUEC) across treatments. Observed median peak BAC (C(max)) for 0.10- and 0.15-g/kg dose groups (median BACs 15.2 and 27 mg/dl, respectively) were very similar to the target C(max) (13 and 26 mg/dl). Analysis of variance of AUEC and E(max) showed difference in impairment measures after the 0.10- and 0.15-g/kg doses. A significant difference in impairment measures between placebo and the active control, 0.45 g/kg (median BAC of 110 mg/dl) was observed, indicating that the methodology was capable of detecting significant psychomotor effects at the legal limit of BAC. Results indicated that the BAC increments from 15 to 27 mg/dl are not associated with significantly impaired performance and, hence, it is unlikely that increases in BAC of this magnitude, such as those caused by ranitidine therapy, are of any clinical relevance.

Neuropsychological performance, disease severity, and depression in progressive supranuclear palsy.

To investigate the relationship between disease severity, cognitive impairment and depression in progressive supranuclear palsy (PSP) we studied a group of 25 patients who fulfilled strict research criteria and 25 matched controls. Disease severity was judged from the duration of symptoms, level of physical disability using the Columbia Rating Scale (CRS), and the degree of eye movement abnormality. The neuropsychological battery was designed to assess attention and executive function, visual and auditory perception, semantic memory and language production. Although the PSP group were significantly impaired on almost all of these measures, the most profound deficits were on tests of sustained and divided attention. There was no correlation between cognitive impairment and either disease duration or scores on the CRS, but performance on tests of attention correlated significantly with the degree of ocular motor impairment. Depression was found to be common in PSP but did not correlate with any other parameters. It is concluded that the cognitive deficit in PSP is widespread and independent of depression. The association between the severity of eye movement disorder and deficits in sustained and divided attention leads us to postulate that pathology involving the midbrain periaqueductal region may be critical for breakdown in these fundamental processes.

Neuropsychological Deficits in Patients with Persistent Symptoms Six Months after Mild Head Injury

There is much debate on the nature and duration of cognitive deficits and postconcussive symptoms (PCS) after mild head injury. Most studies performed so far have compared head-injured patients with subjects who had not suffered a concussion, instead of directly comparing patients with and without persistent PCS. The present study examined whether patients with PCS (n = 9) about 6 months after an uncomplicated mild head injury performed less well on selected neuropsychological tests than patients with mild head injuries who did not have PCS (n = 9) and healthy controls (n = 9). Patients with PCS were individually matched with controls for the time elapsed after the injury, age, sex, and education. We found that patients with PCS performed less well on tests of divided and selective attention than both patients without PCS and healthy controls. It is concluded that cognitive deficits may be present up to 6 months after mild head injury when symptoms persist. The findings indicate that patients with mild head injury and subjective symptoms may manifest demonstrable cognitive deficits.

Traumatic brain injury: A comparison of three clinical tests, and analysis of recovery

Abstract Three commonly used clinical tests of divided attention and information-processing speed, the Trail Making Test, Auditory Short Term Memory Test under Interference, and Paced Auditory Serial-Addition Test, were administered to two groups of traumatic brain injury (TBI) patients; the performances of both groups were compared to those of matched control subjects. Group I consisted of 26 outpatients previously hospitalized for TBI of varying degrees of severity. Group II was composed of 22 nonhospitalized mildly concussed patients. One purpose of the study was to compare the sensitivity of the three tests to the effects of TBI. A second purpose was to assess the course of recovery in the concussed patients as measured by these same tests. All tests significantly discriminated the control subjects from the hospitalized TBI patients. Only the Auditory Short Term Memory test was sufficiently sensitive to differentiate the concussed patients from their control group. After mild concussion, a significant...

Subtle neuropsychological deficits in patients with good recovery after closed head injury.

This study demonstrates residual mental deficits in patients who have apparently recovered after closed head injury. Twenty closed head injury patients were compared to 20 normal control subjects matched for age, sex, handedness, education, language, and IQ. All received a series of neuropsychological tests. Discriminant function analysis significantly differentiated the two groups. Correct classification of individuals as having suffered a head injury or not was 85%. The head injury patients did have primary impairment on tests of divided attention. Litigation was not a factor. We propose that this impairment of information processing reflects residual brain damage secondary to the closed head injury.

ACUTE EFFECT OF ANTIPYRETIC ANALGESICS, ALONE OR IN COMBINATION WITH ALCOHOL, ON HUMAN PSYCHOMOTOR SKILLS RELATED TO DRIVING

1 The effect of acetylsalicylic acid (1 g), indomethacin (50 mg), and phenylbutazone (200 mg) on psychomotor skills was examined double blind on 180 volunteer students. Ninety students received ethyl alcohol (0.5 g/kg) and 90 subjects an equal volume of placebo drink in combination with the drugs. 2 Psychomotor skills were measured with a choice reaction test, two co-ordination tests, and a divided attention test, having correlation with traffic behaviour. The subjects assessed their feelings of performance by means of a rating scale. The tests were done 30, 90 and 150 min after the administration of the agents. 3 Acetylsalicylic acid proved inactive whereas both indomethacin and phenylbutazone impaired eye-hand co-ordination and divided attention. Acetylsalicylic acid did not interact with alcohol to a measurable extent whereas indomethacin in combination with alcohol proved less harmful than without it. The deleterious effects of phenylbutazone and alcohol were additive. 4 An impairment of psychomotor skills related to driving by indomethacin and phenylbutazone should be considered when prescribing these drugs to active out-patients.