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PubMed2005

Neural basis of auditory-induced shifts in visual time-order perception.

Attended objects are perceived to occur before unattended objects even when the two objects are presented simultaneously. This finding has led to the widespread view that attention modulates the speed of neural transmission in the various perceptual pathways. We recorded event-related potentials during a time-order judgment task to determine whether a reflexive shift of attention to a sudden sound modulates the speed of sensory processing in the human visual system. Attentional cueing influenced the perceived order of lateralized visual events but not the timing of event-related potentials in visual cortex. Attentional cueing did, however, enhance the amplitude of neural activity in visual cortex, which shows that attention-induced shifts in visual time-order perception can arise from modulations of signal strength rather than processing speed in the early visual-cortical pathways.

Acoustic Stimulation↗

PubMed1988

Evaluation of a remedial programme for attentional deficits following closed-head injury.

Although the frequency and implications of disorders of attention in head-injured subjects have been recognised in recent years, there have been few carefully controlled attempts to evaluate remedial interventions. The present study employed a multiple baseline across subjects design to evaluate a computer-mediated programme for the remediation of deficits in speed of information processing in 10 severely head-injured subjects, aged 17-38 years. Following a baseline period, the effectiveness of computer training alone was compared with that combined with therapist feedback and reinforcement in separate training phases, each lasting 3 weeks. The final phase involved a return to baseline conditions. Dependent measures of attention, taken across all phases, included psychometric measures of processing speed, a rating scale completed by the patient's Occupational Therapist, and a video of the patient working in therapy. Results suggested that, once spontaneous recovery and practice effect were controlled, the patients showed little response to the interventions in terms of the dependent measures used.

Adolescent↗

PubMedDate not supplied

Neuropsychological functioning following a spinal cord injury.

Studies indicate that 10-60% of the spinal cord injury (SCI) population retains residual cognitive deficits following the injury. However, previous studies have not used a comprehensive neuropsychological battery and/or a well-matched control group. In addition, no study has determined if cognitive deficits continue more than one year after injury. The present study addressed these limitations by comparing the performance of a chronic SCI group (Mean = 17 years post-injury) and a well-matched control group in four cognitive areas. Memory, visuospatial skills, attention/executive functioning, and processing speed were assessed. Results from a discriminant function analysis indicated that information processing speed best differentiated between the SCI and control groups. Twenty-nine percent of the SCI group performed 1 to 2 standard deviations below the control group mean. These results could not be attributed to psychological status or history of alcohol consumption. The findings emphasize the importance of neuropsychological evaluation after SCI.

Journal Article↗

PubMed2001

Cognitive effects in dichotic speech testing in elderly persons.

OBJECTIVE: To study the effect of chronologic age on central auditory functions using dichotic speech tests and to study whether and how the age effect in dichotic listening is related to cognitive ability. DESIGN: Dichotic speech tests and cognitive tests were performed on 30 bilaterally hearing-impaired subjects, with a pure-tone average better than 50 dB HL. They were between 42 and 84 yr of age and were divided into an older and a younger group comprising 15 subjects each. The dichotic test material were digits, low-redundancy sentences and consonant-vowel syllables. The subjects reported stimuli heard in both ears (free report) or in one ear (directed report to left or right ear). The cognitive test battery comprised tests focusing on short-term memory, verbal information-processing speed and phonologic processing. RESULTS: A decreased overall performance in all dichotic speech tests was observed in the older group. In the syllable test the older subjects showed poorer results when focusing on the stimuli heard in the left ear, as compared with when focusing on stimuli heard in the right ear, whereas the younger group showed almost equal results for left- and right ear-focusing conditions. An age effect was also seen in reaction times recorded in the cognitive tests and in the scores of the reading span test. These cognitive parameters correlate with the results of the dichotic test when focusing to the left, but not when focusing to the right in the directed report condition. In the free report condition the overall performance showed a high correlation with cognitive test parameters. CONCLUSIONS: Effects of chronologic age in dichotic speech tests in the elderly have been verified. The degree of effect is dependent on test material, way of reporting and focusing condition. The different listening tasks in dichotic tests put different demands on cognitive ability shown by a varying degree of correlations between cognitive function and dichotic test parameters. Also, the results indicate a strong connection between age-related cognitive decline in the elderly and problems to perceive stimuli presented to the left ear.

Adult↗

PubMed1998

Is nondipping in 24 h ambulatory blood pressure related to cognitive dysfunction?

OBJECTIVE: Associations between the outcome of 24 h ambulatory monitoring and cognitive performance were studied in order to evaluate the potential relevance of ambulant blood pressure status to brain function. It was hypothesized that a small daytime-night-time difference in mean blood pressure (nondipping) is associated with reduced cognitive performance, in line with studies in hypertensive subjects that have reported associations between nondipping and target-organ damage. METHODS: The study followed a cross-sectional design and was part of a larger research programme on determinants of cognitive aging (Maastricht Aging Study, MAAS). A group of 115 community residents aged 28-82 years was recruited from a general practice population and screened for cardiovascular events and medication use. All underwent 24 h blood pressure monitoring. Cognitive performance was measured with tests of verbal memory, attention, simple speed and information processing speed. RESULTS: Mean daytime or night-time levels of both systolic and diastolic blood pressure were unrelated to cognitive outcome, when age, sex and educational level were controlled for. Differences between mean daytime and night-time blood pressure (based on both narrow and wide measurement intervals for day and night-time periods) were positively associated with memory function (5-9% of additional variance explained) and one sporadic positive association was found on the sensorimotor speed score (4%). Nondippers (n=15) showed lower levels of both memory and sensorimotor speed scores. CONCLUSIONS: Ambulatory blood pressure status was not associated with cognitive performance. A reduced nocturnal blood pressure drop was associated with quite specific cognitive deficits, but the underlying mechanism remains to be determined.

Adult↗

PubMedDate not supplied

Toward understanding age-related memory loss in late adulthood.

BACKGROUND: While laboratory tests indicate that older adults typically perform more poorly than do younger adults on many types of memory tasks, the question arises as to whether, or to what extent, it is valid to attribute these differences to ageing per se or to some variable or class of variables that intervene between age and remembering. OBJECTIVE: The purpose of this review is to present three current views that might explain the relationship between age and remembering. They can be construed as variants on resource theories and include: the processing speed hypothesis, the executive function hypothesis, and the common cause hypothesis. METHODS: The review samples results pertinent to these hypotheses that derive from behavioural research. Studies involving various imaging techniques were considered beyond the scope of the review. RESULTS: The balance of research strongly implicates reductions in the speed of information processing as a fundamental contributor to normal age-related memory loss. Nonetheless there are circumstances where other mechanisms, such as working memory, executive function, and sensory processes, are important. CONCLUSION: Despite the phenomenological and empirical reality of age-related memory loss and the breadth of attempts to explain it, much work remains to be done to understand why it occurs. Contemporary debates about the nature and means of identifying shared and unique effects promise to shape future directions for research on memory aging.

Adult↗

PubMed2002

Factor structure of MicroCog in a clinical sample.

Two factor solutions adequately describe the MicroCog performance data of a clinical sample of substance abusers. Information Processing Speed and Information Processing Accuracy factors seem to explain the Short Form and Standard Form scores of a clinical sample as they do for the normative sample. Clinicians need to be aware that the factor scores do not allow for unambiguous interpretation, but may be more meaningful than independent domain scores.

Cognition Disorders↗

PubMed1993

Memory in patients with cerebellar degeneration.

Eleven patients with relatively selective cerebellar degeneration and 11 normal control subjects underwent a comprehensive neurologic and neuropsychological examination. The neuropsychological tests assessed general intellectual ability, different aspects of memory (effortful, automatic, and implicit memory processes), speed of information processing, and verbal fluency (using both category and letter fluency tasks). The results indicated that cerebellar patients were significantly impaired only on tasks requiring the use of executive functions, such as the initiation/perseveration subtest of the Mattis Dementia Rating Scale or the fluency tests, and on memory measures requiring greater processing effort. They performed normally on automatic and implicit measures of memory. Performance on the effortful memory and executive measures was not associated with neurologic variables or mood state. After controlling for the initiation/perseveration deficit, the effortful memory scores of the cerebellar patients were no longer different from those of controls. The present study suggests that memory in patients with relatively pure cerebellar dysfunction is only partially compromised and that the impairment is secondary to a deficit in executive functions.

Adult↗

PubMed1999

Relationship between choice reaction time and the Tower of Hanoi test.

The aim of this study was to examine a possible relation between the speed of information processing, as measured by simple and choice visual RT, and problem-solving, as measured by the Tower of Hanoi test. For 20 normal teenagers, performing all tests, significant correlations were found between choice RT and both measures of performance on the Tower of Hanoi, number of disk moves, and time taken to complete the task. Simple RT was correlated with Completion time but not with the number of moves, while the reverse pattern was discerned for decision time. Choice movement time was also associated with both measures, but simple movement time was not. These results are consistent with the hypothesis of a common neurobiological basis to information-processing speed and executive functions.

Adolescent↗

PubMed2000

Novel learning abilities after traumatic head injury in children.

The cognitive abilities of 69 children with traumatic head injury (THI) were evaluated with the California Verbal Learning Test-Children's Version (CVLT-C; Delis, Kramer, Kaplan, & Ober, 1994), the Children's Category Test (CCT; Boll, 1993), and the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; Wechsler, 1991). Compared to children with mild to moderate injuries, children with severe THI demonstrated statistically significant impairments on the CVLT-C Total T-score as well as the WISC-III Processing Speed index, but findings for the CCT were less robust. Longer length of coma and male gender were associated with relatively poorer performance on the CVLT-C. Children with severe THI demonstrated difficulties with both capacity and speed of information processing, which could not be accounted for by attentional or general verbal knowledge factors. It is concluded that the combination of the CVLT-C and the WISC-III is useful in the evaluation of cognitive sequelae of THI but that findings from the CCT must be considered with some caution in this population.

Journal Article↗

PubMed2003

Development and validation of a web-based neuropsychological test protocol for sports-related return-to-play decision-making.

The Concussion Resolution Index (CRI) is an online assessment tool designed to track resolution of symptoms following sports-related concussion. The CRI is composed of six subtests measuring reaction time, visual recognition, and speed of information processing. Three factors are derived from the subtests: Simple Reaction Time (SRT), Complex Reaction Time (CRT), and Processing Speed (PS). Multiple alternate forms within subtests afford simple, reliable, assessment of change, relative to a baseline test completed by an athlete. The test also assesses self-reported neurophysiological symptoms at the time of injury and tracks resolution of these symptoms. The data demonstrate the CRI is a valid and reliable measure of cognitive performance in a relatively heterogeneous group of athletes aged 13-35. Two methods of statistical analysis for assessing change from baseline were compared to establish a psychometric basis for return-to-play decision-making: the Reliable Change Index (RCI) and multiple regression. Multiple regression was more accurate than the RCI in determining a decline in performance relative to the baseline.

Adolescent↗

PubMedDate not supplied

[Multiple sclerosis and depression].

INTRODUCTION: Depression has frequently been reported in multiple sclerosis. However, prevalence rates must be interpreted in the light of the conceptual and methodological limitations of these studies. Depression has traditionally been associated with response to the diagnosis of this disease, the presence of physical and cognitive limitations, the damage of specific neural systems and inmunomodulatory therapy. AIMS: To assess the evolution of emotional state and its relationship with motor and cognitive slowness, in relapsing remitting patients with minimal levels of neurological disability. PATIENTS AND METHODS: Data are reported for 35 patients with relapsing remitting multiple sclerosis, 27 treated with interferons and 8 without interferon treatment. Mood disturbance (Beck Depression Inventory, BDI), physical disability (Kurtzke Expanded Disability Status Scale, EDSS) and speed of information processing (reaction times) were assessed. The first testing was carried out before the start of treatment and the second testing one year later. RESULTS AND CONCLUSIONS: The group of patients showed a total BDI score indicative of minimal depression associated with items expressing performance difficulties and somatic complaints. Emotional state was not related to physical disability but was related to processing speed measures. A significant improvement of depression was observed after one year of treatment with inmunomodulatory therapy.

Adult↗

PubMed1987

E-speed dental films processed with rapid chemistry: a comparison with D-speed film.

Image quality of E-speed film processed in four rapid chemistry solutions was evaluated and compared to that of D-speed film. One-hundred-twenty films (60 E-speed and 60 D-speed) were exposed with the use of a quality-control phantom and processed in four different rapid solutions. The images were evaluated for speed, contrast, fog and base, resolution, and granularity, and the useful lifetime of the solutions was determined. E-speed film processed with rapid chemistry produced images equal in quality to D-speed film in the range tested (70 to 90 kVp). Fog and base levels of E-speed film were greater than those of D-speed film. The resolution and granularity of the images were equal and were judged adequate in both film types, regardless of the chemistry used. Rapid processing solutions were found to have a 10% to 15% shorter useful lifetime with E-speed film than with D-speed film. The processing of E-speed film in rapid chemistry is recommended for emergency care and endodontics.

Densitometry↗

PubMed1996

Attention deficits and dual task demands after mild traumatic brain injury.

Attention deficits are a prominent aspect of cognitive dysfunction after mild traumatic brain injury (MTBI). Patients frequently complain of distractibility and difficulty attending to more than one thing at a time, and several neuropsychological studies have found evidence for a specific attention deficit without general neuropsychological impairment. The present study examined the nature of attentional disturbance after MTBI using an extended version of the 2 and 7 Test, which introduced two conditions reflecting patients' subjective complaints: the ability to perform with background 'noise', and while simultaneously attending to a secondary task. The dual task demands produced a significant slowing in processing speed for both the MTBI patients and control subjects. However, the relative decline in processing speed appeared much greater for the patients with MTBI, and they differed from control subjects only in this condition. The results are consistent with findings that patients with MTBI exhibit relatively subtle cognitive deficits which are apparent primarily under conditions which require effortful or controlled cognitive processing and exceed their available cognitive resources. Thus, the attentional deficits apparent during dual task demands may represent decreased cognitive, and perhaps neural, efficiency which reflects MTBI patients' subjective complaints and functional impairments.

Adult↗

PubMed2005

White matter hyperintensities are related to physical disability and poor motor function.

OBJECTIVE: To determine the impact of white matter hyperintensities (WMHs) on physical health and cognitive function in 60-64 year old individuals residing in the community. METHODS: A subsample of 478 persons aged 60-64 from a larger community sample underwent brain magnetic resonance imaging (MRI) scans. WMHs on T2 weighted FLAIR (fluid attenuated inversion recovery) MRI scans were assessed using an automated procedure. Subjects were assessed for global cognitive function, episodic memory, working memory (digit span), information processing speed (Symbol Digit Modalities Test; SDMT), fine motor dexterity (Purdue Pegboard), and grip strength, and completed the Physical Component Summary of the Short Form Health Survey (SF-12). Regression analyses were used to examine the effect of WMHs on physical and cognitive function. RESULTS: Deep and periventricular WMHs were present in all subjects, with women having slightly more lesions than men. WMHs were significantly associated with poorer reported physical health on the SF-12 scale, after adjusting for depression, cognitive function, and brain atrophy. WMHs were also related to lower scores on the Purdue Pegboard test, grip strength, choice reaction time, and SDMT, but not on tests of episodic memory, working memory, general intellectual function, and global cognitive function. On regression analyses, the Purdue Pegboard test and grip strength were related to physical disability. CONCLUSION: WMHs are common, albeit mild, in middle adult life. They are associated with physical disability, possibly through reduced speed, fine motor coordination, and muscular strength. They are also related to slowed information processing speed but not other cognitive functions.

Automation↗

PubMed2006

Prefrontal modulation of working memory performance in brain injury and disease.

The inter-related cognitive constructs of working memory (WM) and processing speed are fundamental components to general intellectual functioning in humans. Importantly, both WM and processing speed are highly susceptible to disruption in cases of brain injury, neurologic illness, and even in normal aging. A goal of this article is to summarize and critique the functional imaging studies of speeded working memory in neurologically impaired populations. This review focuses specifically on the role of the lateral prefrontal cortex in mediating WM performance and integrates the relevant WM literature in healthy adults with the current findings in the clinical literature. One important finding emerging from a summary of this literature is the dissociable contributions made by ventrolateral and dorsolateral prefrontal cortex (VLPFC and DLPFC) in guiding performance on tasks of WM. Throughout this review, it is shown that when cerebral resources are challenged, it is DLPFC, and often right DLPFC specifically, that plays a critical role in modulating WM functioning. In addition, this article will examine the relationship between task performance and brain activation across studies to clarify the role of increased DLPFC activity in clinical samples. Finally, explanations are offered for the observed increased DLPFC activation and the potentially unique role of right DLPFC in mediating WM performance during periods of cerebral challenge.

Animals↗

PubMed2004

A genetic investigation of the covariation among inspection time, choice reaction time, and IQ subtest scores.

Information processing speed, as measured by elementary cognitive tasks, is correlated with higher order cognitive ability so that increased speed relates to improved cognitive performance. The question of whether the genetic variation in Inspection Time (IT) and Choice Reaction Time (CRT) is associated with IQ through a unitary factor was addressed in this multivariate genetic study of IT, CRT, and IQ subtest scores. The sample included 184 MZ and 206 DZ twin pairs with a mean age of 16.2 years (range 15-18 years). They were administered a visual (pi-figure) IT task, a two-choice RT task, five computerized subtests of the Multidimensional Aptitude Battery, and the digit symbol substitution subtest from the WAIS-R. The data supported a factor model comprising a general, three group (verbal ability, visuospatial ability, broad speediness), and specific genetic factor structure, a shared environmental factor influencing all tests but IT, plus unique environmental factors that were largely specific to individual measures. The general genetic factor displayed factor loadings ranging between 0.35 and 0.66 for the IQ subtests, with IT and CRT loadings of -0.47 and -0.24, respectively. Results indicate that a unitary factor is insufficient to describe the entire relationship between cognitive speed measures and all IQ subtests, with independent genetic effects explaining further covariation between processing speed (especially CRT) and Digit Symbol.

Adolescent↗

PubMed2026

Beyond Glycaemia: Fear of Hypoglycaemia, Cognition and Functional Mobility After Advanced Hybrid Closed-Loop Therapy in Older Adults With Type 1 Diabetes: A Prespecified Secondary Analysis of a Randomised, Single-Centre Study.

BACKGROUND: Evidence on psychological, cognitive and functional outcomes of advanced diabetes technologies in older adults with long-standing type 1 diabetes (T1D) remains limited. We evaluated whether initiation of advanced hybrid closed-loop (AHCL) therapy was associated with changes in fear of hypoglycaemia, diabetes distress, psychological well-being, cognition, frailty-related measures and mobility-related function in adults aged ≥ 65 years with T1D. METHODS: This prespecified, exploratory secondary analysis was conducted within a single-centre, open-label, randomised, controlled, parallel-group trial including adults aged ≥ 65 years with long-standing T1D. Participants were randomly assigned (1:1) to initiate AHCL therapy using the MiniMed 780G system or to continue standard diabetes treatment. The secondary outcomes included WHO-5, the 17-item Diabetes Distress Scale (DDS), Hypoglycemia Fear Survey-II (HFS-II), Montreal Cognitive Assessment, Digit Symbol Substitution Test, Fried frailty phenotype and performance-based functional measures. No formal sample-size calculation was performed for these secondary outcomes. RESULTS: Thirty-one participants were randomised and 29 completed 12 months of follow-up and were included in the treatment-effect analyses. In the baseline-adjusted primary analysis, AHCL therapy was associated with a lower HFS-II score than standard treatment (adjusted mean difference -18.9; 95% CI: -32.4 to -5.4; nominal p = 0.008), although this finding did not remain statistically significant after Holm correction (adjusted p = 0.104) or in an exploratory model additionally adjusted for sex (difference -13.6; 95% CI: -32.2 to 5.0; p = 0.145). Diabetes distress, psychological well-being, global cognition and processing speed did not differ between groups. In sex-adjusted sensitivity analyses, the between-group differences remained statistically significant for 6-min walk distance (92.6 m; 95% CI: 36.8 to 148.3; p = 0.002) and Timed Up and Go performance (-2.27 s; 95% CI: -4.28 to -0.27; p = 0.028), but not for gait speed (0.27 m/s; 95% CI: -0.05 to 0.59; p = 0.099). At 12 months, 12 of 14 AHCL participants were robust and 2 were pre-frail; in the control group, 11 of 15 were robust and 4 were pre-frail. No participant was classified as frail at follow-up. CONCLUSIONS: In this small, selected cohort, AHCL therapy was associated with a nominally lower fear-of-hypoglycaemia score and better performance on selected mobility-related tests over 12 months. The fear-of-hypoglycaemia finding did not remain statistically significant after correction for multiple comparisons or additional adjustment for sex. Six-minute walk distance and Timed Up and Go remained statistically significant in the exploratory sex-adjusted sensitivity analyses, whereas the gait-speed difference did not. No measurable between-group deterioration in global cognition or processing speed was observed. These exploratory findings require confirmation in larger studies with balanced representation by sex and direct measurement of physical activity. These findings also support a person-centred clinical message: older age alone should not be regarded as a barrier to AHCL when treatment is introduced with individualised education and appropriate ongoing support.

Humans↗