Hospital-at-home care for exacerbations of chronic obstructive pulmonary disease: an observational cohort study of patients managed in hospital or by nurse practitioners in the community

The Urgent Care Team (UCT) in Sunderland (pop. 293,000) is a unique nurse practitioner service operating a hospital at home 24/7/365 to deal promptly with patients suffering an exacerbation of their COPD (AECOPD). Treatment is according to patient group directions utilising nebulised bronchodilators, doxycycline and prednisolone. To compare the health status and pathophysiology during and two months after an AECOPD in 60 UCT patients (31 male) and 30 hospital-managed patients (16 male). The St. Georges Respiratory Questionnaire (SGRQ), Mahler Baseline Dyspnoea Index (BDI) and MRC dyspnoea score recorded health status. Spirometry, BMI and grip strength were also measured. All patients were reviewed 2-3 months after the AECOPD. Changes from BDI were measured using the Transitional Dyspnoea Index (TDI). Mean FEV1% predicted was 47%. In the recovery phase the two groups were comparable for all variables. But during their AECOPD hospitalised patients had a significantly lower BDI (P < 0.05) and an oxygen saturation ranging from 84 to 93% compared with 87-96% for UCT patients. Paired t-tests indicated that on recovery SGRQ activity domain and TDI measures improved in both groups. No deaths occurred during these AECOPDs. A hospital-at-home scheme for AECOPDs can deal with patients who have severe COPD safely. The Mahler TDI appears to be a sensitive index of improvement after an AECOPD.

Short Article: The influence of task characteristics on younger and older adult motor overflow

This study investigated the influence of attentional and motor demands on motor overflow in 17 healthy young (18–35 years) and 17 older adults (60–80 years). Participants performed a finger pressing task by exerting either 33% or 66% of their maximal force output using their dominant or nondominant hand. Overflow was concurrently recorded in the passive hand. Attention was manipulated via a tactile stimulus presented to one or both hands for certain trials. Results showed that older adults exhibited greater overflow than young adults and that the effect of target force was exacerbated in older adults. Further, only older adult overflow was increased when tactile stimulation was directed to one or both hands. Increased overflow in older adults may result from bilateral cortical activation that is influenced by increased task demands. To perform comparatively to younger adults, older adults may compensate for age-related brain changes by recruiting an increased cortical network.

Attention, inhibition, and proximity to clinical onset in preclinical mutation carriers for Huntington's disease

Research in preclinical mutation carriers for Huntington's disease (HD) aims to find measures sensitive to preclinical decline. This study investigated attentional abilities in mutation carriers and noncarriers. Mutation carriers demonstrated a normal "attentional blink" during rapid serial visual presentation, normal covert visual orienting, and normal directing of attention to tactile stimuli. However, they were more likely than noncarriers to make anticipatory responses before target presentation. Additionally, those closer to estimated onset of HD demonstrated larger "inhibition of return" effects. The findings suggest potential changes in cognitive inhibition of unwanted responses, and in automatic inhibition of visual orienting, in preclinical HD.

Progressive Age-Related Changes in the Attentional Blink Paradigm

Previous studies on aging and attention typically examine group differences between younger and older adults, rather than seeing aging as a continuous process. Using correlational analyses, this study examined progressive changes in the magnitude of the attentional blink (AB) associated with aging. Increased age was found to be significantly associated with the ability to detect the second target (T2), whereby older age was correlated with the production of a longer and more pronounced AB; this supports the proposition that aging is associated with reduced inhibitory processes and selective attention. It was also found that AB performance somewhat improves between ages 18-39 years, but tends to decline from 40 years of age onward, providing an interesting and novel finding that AB effects may become more sensitive at this point in time. The AB task may prove useful in the assessment of selective attention in normal healthy adults, as well as changes associated with pathological aging.

The effects of age and attention on motor overflow production—A review

Motor overflow refers to overt involuntary movement, or covert muscle activity, that sometimes co-occurs with voluntary movement. Various clinical populations exhibit overflow. Motor overflow is also present in healthy children and the elderly, although in young adults, overt overflow is considered abnormal unless elicited under conditions of extreme force or muscle fatigue. Current theories of overflow imply that the corpus callosum may mediate production of this phenomenon. However, given that the corpus callosum is a conduit enabling the transfer of cortical information, surprisingly few studies have considered the cortical or subcortical structures underlying overflow. This review considers the developmental trend of motor overflow production, specifically in the upper-limbs, and the mechanisms thought to underlie this age-related phenomenon. Potential neurological correlates of motor overflow will be discussed in conjunction with higher order attentional processes which also regulate motor overflow production. Future research investigating the impact of attentional processes on overflow production may be particularly valuable for designing rehabilitation strategies for patients experiencing induced pathological overflow or conversely, to develop techniques to encourage the recovery of movement function in individuals with paretic limbs.

Proximity to clinical onset influences motor and cognitive performance in presymptomatic Huntington disease gene carriers

BACKGROUND

Neuroimaging studies of Huntington disease (HD) gene carriers have shown that characteristic striatal atrophy begins long before symptom onset, but findings regarding the presence of preclinical functional deficits are inconsistent.

OBJECTIVE

To further investigate potential motor and cognitive deficits in presymptomatic gene carriers (PSGCs), and relationships between performance and estimated proximity to HD symptom onset.

METHOD

PSGCs and age-matched controls performed motor tasks involving cued sequential button presses, and cognitive tasks involving simple and complex choice responses to visuospatial stimuli.

RESULTS

PSGCs demonstrated similar motor performance speed, and nonsignificantly slower cognitive reaction times, to controls. PSGCs made more errors than controls to stimuli requiring a spatially incongruent response, possibly suggesting some difficulty in inhibiting automatic responses. Movement times for motor conditions where little advance information was provided, and reaction times for low demand cognitive tasks, were positively correlated with PSGCs' estimated probability of symptom onset within 5 years.

CONCLUSIONS

Response speed was slower for those PSGCs estimated to have higher probabilities of close onset. These findings suggest that to provide improved knowledge of how HD begins, knowledge that may be used in clinical trials, future research should further explore relationships between function and proximity to onset.

Functional connectivity of the prefrontal cortex in Huntington's disease

BACKGROUND

Huntington's disease is a progressive neurodegenerative disorder that results in deterioration and atrophy of various brain regions.

AIM

To assess the functional connectivity between prefrontal brain regions in patients with Huntington's disease, compared with normal controls, using functional magnetic resonance imaging.

PATIENTS AND METHODS

20 patients with Huntington's disease and 17 matched controls performed a Simon task that is known to activate lateral prefrontal and anterior cingulate cortical regions. The functional connectivity was hypothesised to be impaired in patients with Huntington's disease between prefrontal regions of interest, selected from both hemispheres, in the anterior cingulate and dorsal lateral prefrontal cortex.

RESULTS

Controls showed a dynamic increase in interhemispheric functional connectivity during task performance, compared with the baseline state; patients with Huntington's disease, however, showed no such increase in prefrontal connectivity. Overall, patients with Huntington's disease showed significantly impaired functional connectivity between anterior cingulate and lateral prefrontal regions in both hemispheres compared with controls. Furthermore, poor task performance was predicted by reduced connectivity in patients with Huntington's disease between the left anterior cingulate and prefrontal regions.

CONCLUSIONS

This finding represents a loss of synchrony in activity between prefrontal regions in patients with Huntington's disease when engaged in the task, which predicted poor task performance. Results show that functional interactions between critical prefrontal regions, necessary for cognitive performance, are compromised in Huntington's disease. It is speculated whether significantly greater levels of activation in patients with Huntington's disease (compared with controls) observed in several brain regions partially compensate for the otherwise compromised interactions between cortical regions.

Increased cortical recruitment in Huntington's disease using a Simon task

Cognitive deficits in Huntington's disease (HD) have been attributed to neuronal degeneration within the striatum; however, postmortem and structural imaging studies have revealed more widespread morphological changes. To examine the impact of HD-related changes in regions outside the striatum, we used functional magnetic resonance imaging (fMRI) in HD to examine brain activation patterns using a Simon task that required a button press response to either congruent or incongruent arrow stimuli. Twenty mild to moderate stage HD patients and 17 healthy controls were scanned using a 3T GE scanner. Data analysis involved the use of statistical parametric mapping software with a random effects analysis model to investigate group differences brain activation patterns compared to baseline. HD patients recruited frontal and parietal cortical regions to perform the task, and also showed significantly greater activation, compared to controls, in the caudal anterior cingulate, insula, inferior parietal lobules, superior temporal gyrus bilaterally, right inferior frontal gyrus, right precuneus/superior parietal lobule, left precentral gyrus, and left dorsal premotor cortex. The significantly increased activation in anterior cingulate-frontal-motor-parietal cortex in HD may represent a primary dysfunction due to direct cell loss or damage in cortical regions, and/or a secondary compensatory mechanism of increased cortical recruitment due to primary striatal deficits.

Age-related differences in cognitive function using a global local hierarchical paradigm

While research suggests that normal ageing is associated with compromised divided attentional processing abilities, such studies are comparatively few in comparison to other areas of attention (e.g. selective attention). The current study sought to examine age-related effects in divided attention using a global/local paradigm in three normal healthy age groups: younger adults (20-40 years), middle-aged (40-60 years), and older adults (61-80 years). In three experiments we sought to examine the ability to process local/global stimuli, ability to divide and switch attention, as well as the influence of a cue on target performance. Experiment 1 revealed global precedence and interference for all age groups; older adults were overall significantly slower in their response times. Experiments 2 and 3 suggest an age-related impairment in dividing and switching attention, which may begin as early as middle age. The findings are considered to reflect reduced inhibitory mechanisms, as well as possible neurobiological changes in the normal ageing process.

The influence of attention and age on the occurrence of mirror movements

This study utilised a finger force task to investigate the influence of attention and age on the occurrence of motor overflow in the form of mirror movements in neurologically intact adults. Forty right-handed participants were recruited from three age groups: 20-30 years, 40-50 years, and 60-70 years. Participants were required to maintain a target force using both their index and middle fingers, representing 50% of their maximum strength capacity for that hand. Attention was directed to a hand by activating a bone conduction vibrator attached to the small finger of that hand. Based on Cabeza's (2002) model of hemispheric asymmetry reduction in older adults, it was hypothesised that mirror movements would increase with age. Furthermore, it was expected that when the attentional demands of the task were increased, motor overflow occurrence would be exacerbated for the older adult group. The results obtained provide support for the model, and qualified support for the hypothesis that increasing the attentional demands of a task results in greater motor overflow. It is proposed that the association between mirror movements and age observed in this study may result from an age-related increase in bihemispheric activation that occurs in older adults, who, unlike younger adults, benefit from bihemispheric processing for task performance.

Examining the development of attention and executive functions in children with a novel paradigm

The development of attention and executive functions in normal children (7-12 years) was investigated using a novel selective reaching task, which involved reaching as rapidly as possible towards a target, while at times having to ignore a distractor. The information processing paradigm allowed the measurement of various distinct dimensions of behaviour within a single task. The largest improvements in vigilance, set-shifting, response inhibition, selective attention, and impulsive responding were observed to occur between the ages of 8 and 10, with a plateau in performance between 10 and 12 years of age. These findings, consistent with a step-wise model of development, coincide with the observed developmental spurt in frontal brain functions between 7 and 10 years of age, and indicate that attention and executive functions develop in parallel. This task appears to be a useful research tool in the assessment of attention and executive functions, within a single task. Thus it may have a role in determining which cognitive functions are most affected in different childhood disorders.

Motor overflow in Huntington's disease

We investigated both motor overflow and ability to control voluntary movement in patients with Huntington's disease (HD). We hypothesised that, compared with controls, overflow would be significantly greater in HD participants and that they would exhibit poorer control of voluntary movement. In a finger flexion task, participants had to maintain target forces representing 25, 50, or 75% of the maximum strength capacity for whichever finger was performing the task; overflow was measured in the corresponding finger of the non-responding hand. HD participants exhibited significantly greater motor overflow than controls, and more difficulty controlling the target force with the active hand. In addition, the degree of overflow in HD participants positively correlated with overall UHDRS motor symptom severity. The presence of exacerbated motor overflow in HD, and its correlation with symptom severity, is an important finding worthy of further investigation.

Motor overflow in schizophrenia

The occurrence of motor dysfunction as a sign of schizophrenia, in addition to being a side effect of medication, has received considerable support in recent years. The current study aimed to systematically investigate both the presence and pattern of one such motor dysfunction, motor overflow. It was hypothesised that patients with schizophrenia would show significantly greater motor overflow than controls, and that the pattern of motor overflow occurrence would also vary significantly between the groups. A finger flexion task was used to examine the presence and pattern of motor overflow. Subjects were asked to maintain target forces, using either their index or small finger, representing 25, 50 or 75% of the maximum strength capacity for whichever finger was performing the task. Patients were found to exhibit significantly greater motor overflow than controls. There were also significant findings with respect to the patterns of motor overflow produced, specifically in regards to fine motor control and performance variability. In summary, patients differed significantly from controls in both the degree and pattern of overflow exhibited.

Psychological factors associated with short-term recovery from total knee replacement

OBJECTIVE

To identify the psychological factors that predict short-term recovery following total knee replacement.

METHOD

A group of 42 patients undergoing total knee replacement received a pre-operative psychological assessment. Four self-report questionnaires were completed: the Pain Coping Strategies Questionnaire; the Short Form Social Support Questionnaire; the Recovery Locus of Control Scale; and the Brief Symptom Inventory. Post-operative outcome was assessed in terms of the number of days taken to achieve key physiotherapy milestones (straight leg raise; 90 degrees bend of the knee) and discharge.

RESULTS

The three response variables were analysed separately using an ordinal regression. Internal locus of control was associated with a shorter time to achieve a straight leg raise. Larger values of catastrophizing were associated with longer times to achieve a 90 degrees bend. There was a trend towards larger values of satisfaction with social support to be associated with an earlier achievement of the 90 degrees bend. No psychological variables were found to be associated with the length of hospital stay.

CONCLUSIONS

As suggested by previous studies, coping style and locus of control appear to be important in the rehabilitation process. The current data suggest that psychological variables could be usefully included in a pre-operative assessment for total knee replacement.

Assessing inhibitory control: a revised approach to the stop signal task

The stop signal task (stop task) is designed to assess inhibitory control and is a frequently used research tool in clinical disorders such as ADHD and schizophrenia. Previous methods of setting stop signal delay and of assessing inhibitory control are problematic. The current study reports two modifications that improve the task as a measure of inhibitory control. The first modification was to set stop signal delays proportional to go mean reaction time (go MRT) to better account for inter-subject variability in go MRT. Twenty-eight normal children were tested, and all standard, stop task dependent measures were obtained when delays were set by this method. The second modification was to calculate a novel dependent measure called the area of inhibition (AOI) which provides a more complete measure of inhibitory control than the slope of the relative finishing time z-scores (ZRFT-slope). Implications for the assessment of inhibitory control in clinical populations are discussed.

Working memory in ADHD: prefrontal/parietal connections

Current theories of dopaminergic and noradrenergic mechanisms, which are thought to be of importance in the regulation of attention are reviewed. A biphasic model of dopaminergic function is described, in which tonic dopamine exerts a suppressive influence on subcortical dopamine systems by altering tonic/phasic dopaminergic relationships. Noradrenergic mechanisms are of importance in modulating sensory processing at the prefrontal cortical level. The work of Silberstein and colleagues utilizing Steady-State Visually Evoked Potential, during the course of an A-X Continuous Performance Task enables examination of the spatial distribution and dynamics of electrical brain activity during the task. The maintenance of activation in the interval between A and X provides a measure of working memory, thought to be related to prefrontal-parietal activation, which is facilitated by administration of methylphenidate to children with ADHD, suggesting that working memory may be a core deficiency in children with ADHD. While tonic dopamine activity in ventral striatum/accumbens gates inhibitory activity, dorsolateral prefrontal-parietal connections allow maintenance of working memory required for goal completion.

The pattern of variation in centipede segment number as an example of developmental constraint in evolution

The range of animal morphologies observed in nature is partly determined by natural selection. However, there is no agreement yet regarding whether it is also partly determined by developmental constraint. Testing for the effects of constraint has been difficult due to the lack of both an appropriate null model and a sufficiently simple system capable of yielding unambiguous results regarding the model's plausibility. Here we examine the case of variation in segment number in geophilomorph centipedes. Curiously, while this ranges between 29 and 191, there are no species in which an even number of segments is observed, in contrast to about 1000 species with odd numbers of segments. It seems unlikely that this distribution of character values is determined by selection alone. Using an approach based on Bayesian inference, we attempt to quantify the probability of obtaining the observed distribution of values given a null model in which developmental constraint is absent. Since this probability is in the region of 10(-20), we conclude that constraint must be involved. We discuss various implications of this conclusion, and comment on the unexpected absence of neoteny and progenesis in centipede evolution. Copyright 1999 Academic Press.

Covert orienting of visual spatial attention in attention deficit hyperactivity disorder: does comorbidity make a difference?

Attentional performance in children with attention deficit hyperactivity disorder (ADHD) with and without comorbid disorders was examined using the Covert Orienting of Visuospatial Attention Task (COVAT) and the Continuous Performance Task (CPT). The relationship between these two tasks was also examined. The results showed no overall differences on the attention tasks between children with ADHD alone and those with ADHD plus other disorders. Compared to non-ADHD control children, children with ADHD showed a deficit in the disengage operation of covert visuospatial attention, suggesting a difficulty in the endogenous mode of orienting. The ADHD children also showed a general performance deficit on the CPT. Although there was a general slowing on both attention tasks in the ADHD group, there was no relationship between invalid cue effect sizes on the COVAT and the CPT measures. These results indicate that these two attention tasks may be tapping both similar and independent underlying cognitive processes in ADHD.

Functional brain electrical activity mapping in boys with attention-deficit/hyperactivity disorder

BACKGROUND

Symptoms of attention-deficit/hyperactivity disorder (ADHD) have been associated with frontal lobe deficits. We used a novel brain electrical imaging method to investigate rapid and continuous changes in brain activity during the continuous performance task (CPT) in normal boys and in boys with ADHD. The amplitude and latency topography of the steady-state visually evoked potential (SSVEP) were examined while subjects performed the "X" version of the CPT (CPT-X; the reference task) and the "A-X" version of the CPT (CPT-AX).

METHODS

Seventeen boys meeting DSM-III-R criteria for ADHD and 17 age-matched controls participated in the study. Brain electrical activity was recorded from 64 scalp sites. During the reference task, subjects pressed a microswitch on the unpredictable appearance of the letter X. During the CPT-AX, subjects were required to press the microswitch on the appearance of the letter X only if an A had preceded it.

RESULTS

In the interval between the appearances of the A and the X of the correct trials of the CPT-AX, control boys showed transient reductions in SSVEP latency at right prefrontal sites. By contrast, boys with ADHD showed no change or an increase in prefrontal SSVEP latency at right prefrontal sites.

CONCLUSION

Our results suggest increased speed of prefrontal neural processing in children without ADHD following a priming stimulus, and a deficit in such processes in children with ADHD.

Evaluation of anticoagulant control in a pharmacist operated anticoagulant clinic

AIMS

To compare the quality of outpatient anticoagulant control before and after the transfer of dosing responsibility to designated trained pharmacists from rotating junior medical staff.

METHODS

All International Normalised Ratio (INR) values for an eight month period either side of the staff changeover were assessed for precision of therapeutic control according to described standards. Allowing for patient associated effects, observed and expected frequencies of "successful" control for the two staff groups were compared under the hypothesis of no association.

RESULTS

INR results (n = 2219) for 382 patients were analysed. For patients in stable therapeutic control, there was no significant difference in performance between the two staff groups. Patients with an INR result "out" of control limits were more likely to be returned "in" to control at their next visit by the pharmacists than by the doctors.

CONCLUSIONS

The quality of anticoagulant control in outpatient clinics benefits from dedicated trained staff using standard protocols.

C-peptide response to oral glucose and its clinical role in elderly people

C-Peptide response to oral glucose was measured in 45 elderly diabetics, in whom final treatment was established on clinical grounds during a 16-18 months follow-up. The diabetic patients comprised 19 ultimately classified as insulin-dependent (IDD) (group 1) and 26 regarded as non-insulin-dependent (NIDD) (group 2). Fifteen matched controls (group 3) and 15 young controls (group 4) were similarly studied. Fasting C-peptide values were lower in groups 1 and 2 (1.48 +/- 0.39 and 2.14 +/- 0.22 ng/ml; mean +/- SEM, respectively) compared with groups 3 and 4 (2.51 +/- 0.16 and 2.71 +/- 0.20 ng/ml, respectively) (p less than 0.001). Peak C-peptide levels were reached at 30 min in healthy young and at 60 min in healthy elderly. All non-diabetic control subjects showed a peak of at least 6.5 ng/ml and an increment of at least 4 ng/ml. The ratio of C-peptide increment/blood glucose increment (100 delta CP/delta BG) at 60 min derived to assess beta-cell function was at least 90 in all healthy subjects. The ratio was less than 10 in 68% of IDD but in only 27% of NIDD patients (p less than 0.01). The 100 delta CP/delta BG was inversely related to the prevailing fasting blood glucose (FBG) (p less than 0.001). These findings suggest that C-peptide response to oral glucose may be a useful test in certain elderly diabetic patients whose insulin dependence is in question.