Compensatory strategies for acquired disorders of memory and planning: differential effects of a paging system for patients with brain injury of traumatic versus cerebrovascular aetiology.

BACKGROUND: Previous studies have demonstrated the effectiveness of paging systems in compensating for everyday memory and planning problems after brain injury, including in individuals with traumatic brain injury (TBI). METHODS: Here, in addition to further analyses of the TBI data from a previous randomised control crossover trial, results are reported from a sub-group of 36 participants with brain injury from cerebrovascular accident (CVA). RESULTS: Results indicate that, as with the TBI group, the pager was effective. However, the pattern of results following cessation of treatment differed. At a group level, TBI participants demonstrated maintenance of pager-related benefits, whereas CVA participants' performance returned to baseline levels. Comparisons of demographic and neuropsychological characteristics of the groups showed that the CVA group was older, had a shorter interval post-injury, and had poorer executive function than the TBI group. Furthermore, within the TBI group, maintenance was associated with executive functioning, such that executive dysfunction impeded maintenance. This correlation remained after controlling for demographic differences between groups. CONCLUSIONS: Together, these findings suggest that executive dysfunction may affect treatment-for example, whether or not temporary use of the pager is sufficient to establish a subsequently self-sustaining routine.

Using a paging system in the rehabilitation of encephalitic patients.

Memory and executive problems following encephalitis are common yet there are few published papers on the successful rehabilitation of such patients. We recently demonstrated (Wilson, Emslie, Quirk, & Evans, 2001; Wilson, Emslie, Quirk, Evans, & Watson, 2005) that a paging system could reduce the everyday memory and planning problems for people with non-progressive brain injury. Among the 143 patients who participated in the 2001 study were four people who had survived encephalitis. Their results are reported here. During a 2-week baseline, the successful task achievement of our four clients ranged from 2-81%. They then received a pager for 7 weeks and task achievement was documented in weeks 6 and 7. All were significantly more successful with the pager than they had been at baseline with success rates ranging from 45-96%. Five weeks after returning their pagers they were monitored once more. One of the encephalitic patients failed to achieve any of his target tasks, returning to baseline level, the other three dropped back a little but were still significantly more successful than at baseline. It is concluded that the paging system can reduce everyday memory and planning problems of patients with encephalitis.

Comparison of pocket-computer memory aids for people with brain injury.

Two styles of pocket computer memory aid were compared as support for people who had sustained non-progressive, closed-head brain injury. A purpose-designed interface provided a diary with auditory alarms, a notebook and links between diary entries and specific notepages. One computer had a physical keyboard, the other did not. Twelve adult volunteers were loaned each computer for 2 months, with a 1 month gap between, in counterbalanced order. It was found that all participants could use the memory aids, and most (83%) found them useful. Little customizing was needed, but amount of use varied widely. Predictors of usage included use of other reminding systems before joining the project, and speed in calculator addition which may reflect working memory. High users preferred the computer with a physical keyboard; low users made more entries with the palm-size computer. These data highlight the need to distinguish ability to use from willingness to use.

Reducing everyday memory and planning problems by means of a paging system: a randomised control crossover study.

OBJECTIVES: To evaluate a paging system designed to improve independence in people with memory problems and executive deficits. METHODS: After a successful pilot study, a randomised control trial was conducted involving a crossover design with 143 people aged between 8 and 83 years. All had one or more of the following: memory, planning, attention, or organisation problems. Most had sustained a traumatic head injury or a stroke although a few had developmental learning difficulties or other conditions. The crossover design ensured that some people received a pager after a 2 week baseline whereas others were required to wait for 7 weeks after the baseline before receiving the pager. Participants were assessed at three time periods-namely, at baseline, 7 weeks, and at 14 weeks postbaseline. RESULTS: More than 80% of those who completed the 16 week trial were significantly more successful in carrying out everyday activities (such as self care, self medication, and keeping appointments) when using the pager in comparison with the baseline period. For most of these, significant improvement was maintained when they were monitored 7 weeks after returning the pager. CONCLUSIONS: This particular paging system significantly reduces everyday failures of memory and planning in people with brain injury.

Enhancing an appointment diary on a pocket computer for use by people after brain injury.

People with memory loss resulting from brain injury benefit from purpose-designed memory aids such as appointment diaries on pocket computers. The present study explores the effects of extending the range of memory aids and including games. For 2 months, 12 people who had sustained brain injury were loaned a pocket computer containing three purpose-designed memory aids: diary, notebook and to-do list. A month later they were given another computer with the same memory aids but a different method of text entry (physical keyboard or touch-screen keyboard). Machine order was counterbalanced across participants. Assessment was by interviews during the loan periods, rating scales, performance tests and computer log files. All participants could use the memory aids and ten people (83%) found them very useful. Correlations among the three memory aids were not significant, suggesting individual variation in how they were used. Games did not increase use of the memory aids, nor did loan of the preferred pocket computer (with physical keyboard). Significantly more diary entries were made by people who had previously used other memory aids, suggesting that a better understanding of how to use a range of memory aids could benefit some people with brain injury.

Improvement or simply practice? The effects of twenty repeated assessments on people with and without brain injury.

Measuring recovery of function may mean testing the same individual many times, a procedure that is inevitably open to improvement due to learning on the specific tests rather than recovery per se. This is particularly likely to be an issue with measures of memory performance. We therefore studied the performance of normal and brain-injured people across 20 successive test sessions on measures of orientation, simple reaction time, forward and backward digit span, visual and verbal recognition, word list learning and forgetting, and on three semantic memory measures, namely, letter and category fluency and speed of semantic processing. Differences in overall performances between the two groups occurred for all tests other than orientation, digit span forward, and simple reaction time, although the tests differed in their degree of sensitivity. The tests varied in the presence or absence of practice effects and in the extent to which these differed between the two groups. Data are presented that should allow investigators to select measures that are likely to optimize sensitivity while minimizing possible confounding due to practice effects.

Text entry on handheld computers by older users.

Small pocket computers offer great potential in workplaces where mobility is needed to collect data or access reference information while carrying out tasks such as maintenance or customer support. This paper reports on three studies examining the hypothesis that data entry by older workers is easier when the pocket computer has a physical keyboard, albeit a small one, rather than a touch-screen keyboard. Using a counter-balanced, within-subjects design the accuracy and speed with which adults over 55 years of age could make or modify short text entries was measured for both kinds of pocket computer. The keyboard computer was the Hewlett Packard 360LX (HP), but the touch-screen computers varied across studies (experiment 1: Apple Newton and PalmPilot; experiment 2: Philips Nino; experiment 3: Casio E10). All studies showed significant decrements in accuracy and speed when entering text via the touch-screen. Across studies, most participants preferred using the HP's small physical keyboard. Even after additional practice with the touch screen (experiments 2 and 3) many entries still contained errors. Experiment 3 showed that younger people were faster but not more accurate than older people at using the touch-screen keyboard. It is concluded that satisfactory text entry on palm-size computers awaits improvements to the touch-screen keyboard or alternative input methods such as handwriting or voice. Interface developments that assist older people typically benefit younger users too.

A neural basis for general intelligence.

Universal positive correlations between different cognitive tests motivate the concept of "general intelligence" or Spearman's g. Here the neural basis for g is investigated by means of positron emission tomography. Spatial, verbal, and perceptuo-motor tasks with high-g involvement are compared with matched low-g control tasks. In contrast to the common view that g reflects a broad sample of major cognitive functions, high-g tasks do not show diffuse recruitment of multiple brain regions. Instead they are associated with selective recruitment of lateral frontal cortex in one or both hemispheres. Despite very different task content in the three high-g-low-g contrasts, lateral frontal recruitment is markedly similar in each case. Many previous experiments have shown these same frontal regions to be recruited by a broad range of different cognitive demands. The results suggest that "general intelligence" derives from a specific frontal system important in the control of diverse forms of behavior.

Adapting the Rivermead Behavioural Memory Test Extended Version (RBMT-E) for people with restricted mobility.

OBJECTIVES: The study aimed to facilitate use of the RBMT-E with people who have impaired mobility by devising substitute tasks for the route and message subtests that do not require the individual to move around, and by presenting normative data for these substitute tasks. DESIGN: A within-subjects design was used to assess a standardization sample. Participants completed two parallel versions of the tasks in counter-balanced order in two test sessions approximately 1 week apart. METHODS: Substitute versions of the route and message subtests not requiring the individual to move around the test room were devised using commercially available materials. These were administered to participants along with other RBMT-E subtests. Scores for each version were compared for the group as a whole and for subgroups divided according to age, gender and IQ. Based on the results, profile scores were derived for each task using box plot analysis. The participants (N = 111) were part of the standardization sample for the RBMT-E and comprised consecutive series of recruits in two centres, Cambridge (UK) and Sydney (Australia). RESULTS: Normative data are presented in the form of mean scores for the group as a whole, for men and women, for people aged under 30, 30 to 50, and over 50 years, and for people with an IQ of either 90-110 or over 110. Profile score transformations for the substitute tasks are provided. CONCLUSIONS: Where mobility problems preclude the use of the route and message subtests of the RBMT-E, the 'model' tasks described here can be substituted and profile scores calculated. This allows clinicians to obtain a full spectrum of subtest scores for the RBMT-E with mobility-impaired patients, thus allowing the calculation of a total profile score.

Measuring recovery from post traumatic amnesia.

Three groups of participants were assessed. Each participant was tested on 20 occasions. The groups comprised people (i) in post traumatic amnesia (PTA) following severe head injury (n=9), (it) with severe head injury but not in PTA (n=10), and (iii) with no history of head injury or other neurological condition (n=13). Subjects were given several tests of memory, attention and learning in order to determine which tests were good at (a) distinguishing people in PTA from those not in PTA, and (b) monitoring recovery over time. The results indicate that people in PTA have a wide range of deficits and their cognitive recovery is a gradual process rather than an all-or-none phenomenon. In terms of measurement, the study suggests that a good test of PTA should include orientation questions, together with a reaction time measure, a visual recognition test and a speed of information processing measure. Most of the tests administered were good at distinguishing between brain-injured and nonbrain-injured people, although only two tests distinguished between the two brain-injured groups, i.e. those in PTA and those out of PTA. Almost all tests were good at monitoring recovery from PTA.

Random generation and the executive control of working memory.

A series of experiments explores the capacity for generating sequences of random responses, relating it to the central executive component of working memory. Experiment 1 shows a broadly similar pattern of redundancy increasing with speed of generation for both the verbal generation of digits and the manual pressing of keys. In both cases deviations from randomness are shown to reflect the increasing use of a limited number of stereotyped response sets. The remaining experiments use keyboard generation. Experiment 2 demonstrates that concurrent immediate serial recall decreases randomness, and that longer recall sequences produce less random output. Experiments 3 and 4 show that whereas simple counting has no effect on randomness, serial recall, semantic category generation, and concurrent digit generation have substantial effects, and a concurrent fluid intelligence test has the greatest influence on the randomness of key pressing. It is suggested that the task of random generation resembles that of category fluency because it requires the subject to switch retrieval plans and inhibit repetition. On this basis it is predicted that a task involving repeated switching of categories will interfere with generation, despite being predictable and having a low memory load. Experiments 5 and 6 confirm this prediction. Strengths and limitations of the switching hypothesis are discussed, as are the implications of our results for the analysis of executive processes.

External cueing systems in the rehabilitation of executive impairments of action.

The use of a mnemonic cueing system (NeuroPage) and a paper and pencil checklist in the rehabilitation of executive problems in a 50-year-old woman are described. Following a CVA 7 years earlier, the patient, despite intact general intellectual and memory functioning, had specific executive impairments of attention, planning, realizing intended actions, and also exhibited behavioral routines similar in form to obsessive-compulsive rituals. In a series of ABAB single-case experimental designs, the efficacy of 2 external cueing systems in prompting appropriately timed action is demonstrated. It is argued that the combination of external control and increased sustained attention to action were critical to the success of NeuroPage with this patient. Furthermore it is hypothesized that the checklist was effective in facilitating the patient's ability to foresee and recognize the consequences of her actions, which in turn had an impact on the probability of her changing those same actions.

The ecological validity of tests of executive function.

Ninety-two mixed etiology neurological patients and 216 control participants were assessed on a range of neuropsychological tests, including 10 neuropsychological measures of executive function derived from 6 different tests. People who knew the patients well (relatives or carers) completed a questionnaire about the patient's dysexecutive problems in everyday life, and this paper reports the extent to which the tests predicted the patients' everyday life problems. All of the tests were significantly predictive of at least some of the behavioral and cognitive deficits reported by patients' carers. However, factor analysis of the patients' dysexecutive symptoms suggested a fractionation of the dysexecutive syndrome, with neuropsychological tests loading differentially on 3 underlying cognitive factors (Inhibition, Intentionality, and Executive Memory), supporting the conclusions that different tests measure different cognitive processes, and that there may be limits to the fractionation of the executive system.

Evaluation of NeuroPage: a new memory aid.

This report describes NeuroPage, a simple and portable paging system, developed in California by the engineer father of a son with head injury working together with a neuropsychologist. Using an ABA single case experimental design, the efficacy of NeuroPage was evaluated with 15 neurologically impaired subjects all of whom had significant everyday memory problems because of organic memory impairment or because of problems with planning and organisation consequent on frontal lobe damage. Data were analysed with an odds ratio test which takes into account different underlying success rates for each target and calculates an average improvement factor. This test showed a significant improvement between the baseline and the treatment phases for each subject (P<0.05).

Intelligence and the frontal lobe: the organization of goal-directed behavior.

Basic to the study of individual differences is the concept of 'general intelligence' or Spearman's g. In this article we suggest that g is largely a reflection of the control functions of the frontal lobe. A series of experiments investigates a phenomenon we call goal neglect: disregard of a task requirement event though it has been understood and remembered. Subjectively it is as though the neglected requirement "slips the subject's mind." Previously described in frontal patients, we show that goal neglect can also be seen in some members of the normal population. In line with conventional distinctions between controlled and automatic processing, eliciting conditions for goal neglect include novelty, weak error feedback, and multiple concurrent task requirements. Under these conditions neglect is linked closely to g and extremely common after frontal lesions. Following many other models, we suggest that behavior in any task is structured by a set of action constraints or requirements, derived in part from verbal instructions and specified at multiple levels of abstraction. A frontal process of constraint or requirement activation is fundamental to Spearman's g.

Fluid intelligence after frontal lobe lesions.

Generally positive correlations between different ability tests provide the evidence for a factor of "general intelligence" or Spearman's g. Though a possible neural substrate for g is suggested by executive impairments following frontal lobe lesions, preserved IQs in some frontal patients have been taken as strong evidence against this interpretation. We show that such results depend on how g is measured. Patients with superior IQs on the most clinically popular test--the Wechsler Adult Intelligence Scale--show impairments of 20-60 points on conventionally measured fluid intelligence or novel problem solving. On psychometric grounds, it is fluid intelligence that is most closely related to Spearman's g. The data suggest that g may in large part be a reflection of frontal functions.

The Children's Test of Nonword Repetition: a test of phonological working memory.

This article presents findings from the Children's Test of Nonword Repetition (CNRep). Normative data based on its administration to over 600 children aged between four and nine years are reported. Close developmental links are established between CNRep scores and vocabulary, reading, and comprehensive skills in children during the early school years. The links between nonword repetition and language skills are shown to be consistently higher and more specific than those obtained between language skills and another simple verbal task with a significant phonological memory component, auditory digit span. The psychological mechanisms underpinning these distinctive developmental relationships between nonword repetition and language development are considered.

The Spot-the-Word test: a robust estimate of verbal intelligence based on lexical decision.

The development of a test aimed at estimating premorbid intelligence is described. The test, Spot-the-Word, involves presenting the subject with pairs of items comprising one word and one non-word, and requiring the subject to identify the word. Data show that performance correlates highly with verbal intelligence as estimated by Mill Hill Vocabulary score and by performance on the National Adult Reading Test (NART). Performance does not decline with age, in contrast to an associated test of verbal recognition memory. A second study attempted to test the effect of intellectual deterioration due to age on Spot-the-Word performance. Elderly subjects who had high vocabulary scores scored well on the Spot-the-Word regardless of whether fluid intelligence as measured by the AH4 test was well preserved, or was low, implying intellectual deterioration. A final study collected normative data on a sample of 224 subjects stratified by age and socio-economic status, with each subject performing two parallel forms of the test, A and B, together with the NART. Correlation between the two forms was .884, while correlation with NART was .831 for Form A and .859 for Form B, suggesting adequate reliability and validity. It is concluded that the test provides a potentially useful additional method of estimating premorbid intelligence.