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Real-time reconstruction and high-speed processing in functional MR imaging.

Access to fully processed activation maps in near real time during a functional MR examination enables run-to-run assessment of results. This is particularly useful in clinical studies, since the results of the functional MR examination can be ascertained before the patient leaves the MR suite, permitting interactive tailoring of the functional MR study. We describe how a real-time MR system can be customized to complete the following tasks in less than 3 minutes: obtain an 81-second acquisition of a multisection functional MR imaging time series using single-shot echo-planar imaging, perform image reconstruction, extract functional MR activation maps using cross-correlation and thresholding, and superimpose activation maps on previously acquired T1-weighted anatomic images.

Algorithms↗

Speed-of-processing and driving simulator training result in improved driving performance.

Useful field of view, a measure of processing speed and spatial attention, can be improved with training. We evaluated the effects of this improvement on older adults' driving performance. Elderly adults participated in a speed-of-processing training program (N = 48), a traditional driver training program performed in a driving simulator (N = 22), or a low-risk reference group (N = 25). Before training, immediately after training or an equivalent time delay, and after an 18-month delay each participant was evaluated in a driving simulator and completed a 14-mile (22.5-km) open-road driving evaluation. Speed-of-processing training, but not simulator training, improved a specific measure of useful field of view (UFOV), transferred to some simulator measures, and resulted in fewer dangerous maneuvers during the driving evaluation. The simulator-trained group improved on two driving performance measures: turning into the correct lane and proper signal use. Similar effects were not observed in the speed-of-processing training or low-risk reference groups. The persistence of these effects over an 18-month test interval was also evaluated. Actual or potential applications of this research include driver assessment and/or training programs and cognitive intervention programs for older adults.

Aged↗

Neurocognition in depression: patients on and off medication versus healthy comparison subjects.

Patients with depression have neuropsychological deficits in attention, memory, psychomotor speed, processing speed, and executive function. It is not clear, however, whether neurocognition in depression is impaired in a global or nonspecific way or if specific cognitive domains are selectively impaired. This naturalistic cross-sectional study employed a computerized neurocognitive screening battery to evaluate 38 depressed, drug-free patients, compared to 31 patients who responded to antidepressant monotherapy and to 69 healthy comparison subjects. There was evidence for global neuropsychological impairment in untreated depressed patients. In patients who had been successfully treated, performance was improved but not normalized. There was also evidence for specific depression-related deficits in executive function and processing speed but not in memory, psychomotor speed, or reaction time. Although depressed patients have global neurocognitive impairments, deficits in certain cognitive domains are more important than in others. In particular, impairments are noted in tests of executive control and in tests that demand effortful attention. Information processing speed is also impaired but not reaction time. Computerized testing in the clinic setting demonstrates a range of neurocognitive problems in patients with depression. These problems may have a bearing on treatment and outcome.

Adolescent↗

Developmental changes in speed of information processing in young children.

This study investigated developmental increases in processing speed in young children, relative to adults, with only nonverbal stimuli. R. Kail's (1991) model of the rate of change in processing speed from childhood to adulthood was evaluated. Processing speed was measured in 34 children at 4 years, 37 at 5 years, and 38 at 6 years and in 43 adults, with a battery of 8 computer-administered tests. Results showed clear age-related increases in processing speed that cannot be attributed to increased accuracy and error rate monitoring. Kail's model adequately accounted for the observed rate of developmental change in processing speed; however, the parameter estimates of R. Kail and Y. Park (1992) provided more accurate predictions than did the meta-analytically derived estimates of Kail (1991). Findings support the global developmental trend hypothesis and suggest that this trend extends beyond the range of verbal skills evaluated in previous research.

Adult↗

Delayed recognition memory in Parkinson's disease: a role for working memory?

Immediate and delayed recognition memory for words was examined in a sample of 16 non-demented patients with Parkinson's disease and 16 normal control participants of equivalent age and educational attainment. The patients, relative to control participants, had intact immediate but impaired delayed recognition memory performance. Patients were also impaired on tests of free and cued recall, working memory and a measure of psychomotor processing speed. Processing speed was a significant covariate for delayed recognition, free and cued recall and working memory performance, but not for immediate recognition performance. These results suggest that the same cognitive processes which support performance on tests of recall and working memory also support performance on tests of delayed recognition.

Aged↗

Speed of processing and individual differences in IQ in schizophrenia: General or specific cognitive deficits?

INTRODUCTION: The aim of this study was to re-examine the role of cognitive processing speed in the vulnerability to schizophrenia, using an inspection time (IT) task that does not require a speeded manual response. Since IT consistently correlates with intelligence, the relationship between IT and general intelligence was also explored. METHODS: Patients with schizophrenia were compared with unaffected siblings of schizophrenia patients and healthy controls on a visual IT task. Both speed and variability of IT performance were examined. Current intellectual ability (IQ) was estimated with the Shipley Institute of Living Scale (SILS), which yields separate assessments of verbal and abstraction abilities. RESULTS: Schizophrenia patients produced ITs that were significantly slower and more variable than either unaffected siblings or healthy controls. These results are not related to demographic or clinical variables. A significant negative correlation was obtained between IT and IQ; specifically, longer IT values were associated with abstraction scores only. CONCLUSIONS: These findings confirm that basic cognitive processing efficiency is impaired in patients with schizophrenia. In contrast, ITs in unaffected siblings did not differ from healthy controls, in line with their better IQ test scores. Implications for models of general and specific heritable dimensions in schizophrenia are discussed.

Journal Article↗

An investigation into the relationship among ADHD symptomatology, creativity, and neuropsychological functioning in children.

This paper examined the relationship between creativity and ADHD symptomatology. First, the presence of ADHD symptomatology within a creative sample was explored. Secondly, the relationship between cognitive functioning and ADHD symptomatology was examined by comparing four groups, aged 10-12 years: 1) 29 ADHD children without creativity, 2) 12 creative children with ADHD symptomatology, 3) 18 creative children without ADHD symptomatology, and 4) 30 controls. Creativity, intelligence, processing speed, reaction time, working memory, and inhibitory control were measured. Results showed that 40% of the creative children displayed clinically elevated levels of ADHD symptomatology, but none met full criteria for ADHD. With regard to cognitive functioning, both ADHD and creative children with ADHD symptoms had deficits in naming speed, processing speed, and reaction time. For all other cognitive measures the creative group with ADHD symptoms outperformed the ADHD group. These findings have implications for the development and management of creative children.

Attention Deficit Disorder with Hyperactivity↗

Addressing the differences in speed of processing of the intervening calculation task on the modified Brown-Peterson task.

The Modified Brown-Peterson task (MBPT) is a task of divided attention and working memory that requires central executive functioning. It is a variant of the Brown-Peterson technique and is useful for studying short-term retention of information. It involves the recall of auditory information under conditions of interference (i.e., counting backwards). Previous research has not addressed the effect of individual differences in processing speed for the intervening calculations. In a sample of 81 young participants, we determined whether the number of correct calculations performed is related to recall performance on the MBPT. Results indicated that the number of calculations performed was not significantly related to the recall performance on the MBPT. Rather, the number of correct calculations performed during the interference task of the MBPT was associated with arithmetic ability as measured by the arithmetic subtest of the Adult Intelligence Scale-III (Wechsler, 1997). These results suggest that the subtractions in the MBPT create interference regardless of mathematical ability or speed at which the subtractions are performed during the interference condition of the MBPT task. This observation suggests that the results on this test are independent of mathematical ability and represent a useful measure of working memory.

Adult↗

Cognitive factors in auditory performance: context, speed of processing, and constraints of memory.

This paper describes several techniques used to explore the role of cognitive factors in auditory performance in elderly adults. Two factors, cognitive slowing and age-related memory constraints, receive special attention. Assessing listeners' ability to report the content of time-compressed speech shows elderly adults to be especially vulnerable to rapid speech input. Such effects, however, are ameliorated by effective use of linguistic knowledge, which, unlike processing speed, remains relatively stable in adult aging. A second technique is described in which intelligibility is tested for words excerpted from fluent speech, first presented in isolation and then with varying amounts of preceding or following context from the original utterances. Memory constraints are shown to have a significant effect on elderly listeners' ability to use linguistic context that follows an acoustically ambiguous region for a retrospective analysis of what had been heard. Thus, cognitive factors can both enhance and limit auditory performance in elderly listeners.

Adolescent↗

Does cognitive function influence alaryngeal speech rehabilitation?

BACKGROUND: We sought to define the cognitive domains that influence valved speech rehabilitation. METHODS: Sixteen laryngectomees with primary tracheoesophageal punctures were randomly recruited from one head and neck unit. They were assessed by a consultant neuropsychologist and a speech therapist. Speech therapy time was determined from speech therapy notes. RESULTS: The Digit Symbol Substitution Test, assessing learning speed and processing speed, correlated significantly with speech therapy time in the first (p = .002) and third (p = .014) postoperative years, respectively. Categorical fluency assessment correlated positively with speech therapy time in the first year (p = .009). Learning speed (p = .007) and categorical fluency (p = .041) correlated positively with the fall in speech therapy input between the first and third year after laryngectomy. CONCLUSIONS: Learning speed, processing speed, and categorical fluency strongly influence alaryngeal speech rehabilitation. This study highlights the potential for pre-laryngectomy cognitive assessment to help plan alaryngeal speech rehabilitation. This has significant resource implications.

Aged↗

A cross-sequential analysis of developmental differences in speed of visual information processing.

Development of processing speed was examined in three backward masking studies. The first verified the central nature of backward masking for children aged 8 and 11 years and for adults. The second suggested that task requirements were equivalent for children similar to those in Study 1, and that age differences in performance were not attributable to nonprocessing variables. The main cross-sequential study estimated speed of processing in 80 children (approximately 6 years to 13 years) and young adults using an inspection time task. Target exposure duration was varied to establish the time required to achieve a high level of discriminative accuracy. Estimates of processing speed increased until about 11-13 years of age; beyond this, the trend was less obvious, and it is possible that inspection time asymptotes at around the onset of adolescence. Performance improvement after 1 year could not be explained as resulting from practice since improvement among controls over a period of 2 weeks was significantly less. Correlations between estimates of inspection time made up to 2 years apart found the measure to be reliable.

Adolescent↗

Recognition of handwritten similar Chinese characters by self-growing probabilistic decision-based neural network.

Recognition of similar (confusion) characters is a difficult problem in optical character recognition (OCR). In this paper, we introduce a neural network solution that is capable of modeling minor differences among similar characters, and is robust to various personal handwriting styles. The Self-growing Probabilistic Decision-based Neural Network (SPDNN) is a probabilistic type neural network, which adopts a hierarchical network structure with nonlinear basis functions and a competitive credit-assignment scheme. Based on the SPDNN model, we have constructed a three-stage recognition system. First, a coarse classifier determines a character to be input to one of the pre-defined subclasses partitioned from a large character set, such as Chinese mixed with alphanumerics. Then a character recognizer determines the input image which best matches the reference character in the subclass. Lastly, the third module is a similar character recognizer, which can further enhance the recognition accuracy among similar or confusing characters. The prototype system has demonstrated a successful application of SPDNN to similar handwritten Chinese recognition for the public database CCL/HCCR1 (5401 characters x200 samples). Regarding performance, experiments on the CCL/HCCR1 database produced 90.12% recognition accuracy with no rejection, and 94.11% accuracy with 6.7% rejection, respectively. This recognition accuracy represents about 4% improvement on the previously announced performance. As to processing speed, processing before recognition (including image preprocessing, segmentation, and feature extraction) requires about one second for an A4 size character image, and recognition consumes approximately 0.27 second per character on a Pentium-100 based personal computer, without use of any hardware accelerator or co-processor.

China↗

[Intelligence and prognosis in severe traumatic brain injury: a neuropsychological study with the Wechsler adult intelligence scale (WAIS-III)].

OBJECTIVE: To evaluate the utility of the Wechsler adult intelligence scale III (WAIS-III) as a measure of intelligence after severe brain injury, and to elucidate prognostic factors associated with intelligence coefficients (IQs). METHODS: Forty-six patients (age: 27.4 +/- 12.8 years) attending our service after a severe head injury were included in our study (chronicity: 315.3 +/- 330 days after injury). All patients were assessed with the WAIS-III. WAIS-III IQs were correlated (Pearson and Spearman) with clinical and demographic data. A significance level of p < 0.05 was used in all comparisons. IQs between 1 and 2 standard deviation (SD) below normative data were considered "mild abnormal" while indexes below 2 SD were considered "abnormal". RESULTS: Only eleven patients (25 %) showed normal total IQ with predominance of manipulative (77.7 %) compared to verbal (64.5 %) impairment. Thirty-eight patients (95 %) had difficulties in speed processing, thirty-six (85.6 %) had problems with working-memory, twenty-five (62.5 %) showed impairments in perceptual organization, and twenty-six (62 %) had verbal comprehension deficits. WAIS-III IQs showed significant correlations with length of coma and posttraumatic amnesia duration (p < 0.05). CONCLUSIONS: The WAIS-III is a valid and sensible tool to detect cognitive deficits associated with brain injury. Almost all patients with severe brain injury show abnormal IQs with a slow processing speed as predominant symptom. Length of coma and posttraumatic amnesia seems to be the most relevant parameter related to intelligence in severe brain-injured patients.

Adolescent↗

The impact of speed of processing training on cognitive and everyday performance.

The purpose of the present investigation was to examine the impact of speed of processing training on the cognitive and everyday abilities of older adults with initial processing speed or processing difficulty. Participants were randomized to either a speed of processing intervention or a social- and computer-contact control group. Results indicate that speed of processing training not only improves processing speed, as indicated by performance on the Useful Field of View test (UFOV), but also transfers to certain everyday functions, as indicated by improved performance on Timed Instrumental Activities of Daily Living (Timed IADL). Transfer of speed of processing training to other cognitive domains was not evident. This study provides additional evidence that speed of processing training has the potential to enhance everyday functions that maintain independence and quality of life, particularly when the training is targeted toward individuals who most need it. Further study is needed to learn about the long-term effects of such training in relation to everyday abilities.

Activities of Daily Living↗

Speed of information processing in patients with multiple sclerosis.

To determine the extent to which multiple sclerosis (MS) slows cognitive processes, speeded tasks were administered to 11 patients with MS and to 11 comparison subjects without MS. On all tasks, patients with MS responded more slowly than comparison subjects. More important, response times (RTs) for patients with MS increased systematically as a function of RTs for comparison subjects, and the increase was best described by a power function. These data are consistent with the view that MS produces a general slowing of cognitive processes, and with the view that the cognitive slowing associated with aging reflects neural noise.

Adult↗

Development and evaluation of home-based speed-of-processing training for older adults.

OBJECTIVES: To develop technical parameters for a videotape-based speed-of-processing training protocol, to evaluate the feasibility of self-administration (experiment 1), and to evaluate the protocol's effectiveness (experiment 2). DESIGN: A feasibility study (experiment 1) and a pre-post, 4-arm, nonrandomized controlled trial (experiment 2). SETTING: University research center. PARTICIPANTS: A population-based sample (37 men, 47 women; age range, 65-94y) (experiment 1). A population-based sample (age > or =65y) with no prior exposure to the Useful Field of View assessment or speed-of-processing training, no dementia or life-limiting illness, a Mini-Mental State Examination score of greater than 24, corrected far visual acuity of greater than or equal to 20/40, contrast sensitivity of greater than or equal to 1.50 log(10), and deficient processing speed (experiment 2). For experiment 2, 8 of 189 eligible people declined to participate. The final sample for this experiment included 100 men and 81 women (age range, 65-91y). INTERVENTIONS: Eight to ten 1-hour cognitive training sessions. MAIN OUTCOME MEASURE: Posttraining gains in processing speed. RESULTS: Self-administration was feasible. Subjects who underwent home-based training improved their processing speed significantly more than either control group (F(3,146)=16.16, P<.001). Their gains were 74% as great as the gains of those who underwent trainer-facilitated speed-of-processing training. CONCLUSIONS: People can improve their processing speed at home using readily available technology. Future research should explore the relation of these improvements to driving performance.

Activities of Daily Living↗

Age differences in fluid intelligence: contributions of general slowing and frontal decline.

The current study examined the contributions of general slowing and frontal decline to age differences in fluid intelligence. Participants aged 20-89 years completed Block Design, Matrix Reasoning, simple reaction time, choice reaction time, Wisconsin Card Sorting, and Tower of London tasks. Age-related declines in fluid intelligence, speed of processing, and frontal function were observed. Hierarchical regression analyses showed that the processing speed and frontal function measures accounted for significant variance in fluid intelligence performance, but there was also a residual effect of age after controlling for each variable individually as well as both variables. An additional analysis showed that the variance in fluid intelligence that was attributable to processing speed was not fully shared with the variance attributable to frontal function. These findings suggest that the age-related decline in fluid intelligence is due to general slowing and frontal decline, as well as other unidentified factors.

Adult↗