An investigation of visuospatial memory impairment in children with attention deficit hyperactivity disorder (ADHD), combined type

BACKGROUND

Memory impairment is not considered a core cognitive feature of attention deficit hyperactivity disorder, combined type (ADHD-CT), although it is associated with impairments in attentional and executive functions. This study investigates visuospatial memory impairment, in particular encoding and retrieval aspects, in children with ADHD-CT who are stimulant-medication naive and medicated with stimulant medication.

METHOD

A cross-sectional study of visuospatial memory in 6- to 12-year-old children with stimulant-medication-naive ADHD-CT (n = 62) and medicated ADHD-CT (n = 58) compared to an age- and gender-matched healthy control group (n = 39) was completed.

RESULTS

Both medication-naive and medicated ADHD-CT groups demonstrated subtle yet significant impairment in visuospatial memory. The memory impairment was delay-independent, which, along with other factors, suggest dysfunction of the encoding rather than retrieval phase of visuospatial memory.

CONCLUSIONS

Careful study of large ADHD-CT samples does detect deficits in a visuospatial memory task, but these reflect attentional deficits rather than being specifically due to dysfunction of the medial temporal lobe explicit memory system. Children with ADHD-CT may benefit from cognitive and behavioural strategies focused on improving encoding of relevant information rather than retrieval strategies.

Contextual abnormalities of saccadic inhibition in children with attention deficit hyperactivity disorder

Abnormalities of executive function are observed consistently in children with attention-deficit hyperactivity disorder (ADHD), and it is hypothesised that these arise because of disruption to a behavioural inhibition system. Executive and inhibitory functions were compared between unmedicated and medicated children with ADHD (combined type), age-matched healthy children and healthy adults. Executive functions were measured using a test of spatial working memory shown previously to be sensitive to ADHD and to stimulant medication. Inhibitory functions were measured using an ocular motor paradigm that required individuals to use task context to control the release of fixation. Context was set according to the probability that a target would appear at either of the two locations. In one block, targets appeared on 80% of trials. In the other block, targets appeared on 20% of trials. The ability to control the release of fixation was inferred from the fixation offset effect (FOE), or the difference in saccade latency when the current fixation is offset 200 ms prior to the onset of the saccade target (gap condition), compared with when there is no offset (overlap condition). Although the healthy children made more errors on the spatial working memory task than the healthy adults, there was no difference between the two groups in their ability to control fixation using context. Both showed a larger FOE when target probability was low. As expected, the unmedicated ADHD group made more errors on the spatial working memory test than the healthy children, although spatial working memory performance was normal in the medicated ADHD group. However, both the unmedicated and medicated ADHD groups were unable to modulate the FOE according to context, and this was due to their inability to voluntarily inhibit saccades when there was a low target probability. These data suggest that the context-based modulation of fixation release is not controlled by the same systems that control executive function. Furthermore, deficits in executive function and inhibitory control appear independent in children with ADHD.

Abnormal executive function in attention deficit hyperactivity disorder: the effect of stimulant medication and age on spatial working memory

OBJECTIVE

This study sought to examine the factors associated with spatial working memory and the use of strategies to impairments in spatial working memory in children with attention deficit hyperactivity disorder (ADHD). The developmental trajectories for spatial working memory in medicated and medication naïve children with ADHD were investigated. In addition, the effect of psychostimulant medication on deficits in spatial working memory was examined.

METHOD

A cross-sectional study compared performance between 21 psychostimulant medicated children with ADHD, 27 medication naïve children with ADHD and 26 matched control subjects on computerized tests of spatial memory and spatial working memory.

RESULTS

Compared with the controls, performance in medication naïve children with ADHD was significantly worse on the spatial working memory task. There was no difference in performance between the medicated children with ADHD and the control subjects on this same task, despite the ongoing symptoms of ADHD in the former group. The pattern of normal and abnormal performance in the ADHD groups was age-independent.

CONCLUSIONS

Deficits in executive functions related to spatial working memory do occur in children with ADHD, although the magnitude of these deficits is not related to the child's age or the level of ADHD symptoms. These deficits were not present in the current sample of children who were receiving psychostimulant medication.

Coping with the costs of primary care? Household and locational variations in the survival strategies of the urban poor

This paper examines the 'survival' strategies adopted by lower income groups seeking to cope with the costs of primary care. Two surveys, one of the health and health service concerns of clients of an inner city voluntary welfare agency, and another of how 114 general practitioner (GP) surgeries in Christchurch, New Zealand aided patients in financial distress, were conducted in October-December, 1997. Patients adopted a variety of strategies, both active and passive, with delays in obtaining medications and seeking financial help from GPs being the most common. Although less important, high rates of switching GPs occurred. There was evidence of geographical variation in the strategies adopted by patients and practices as well as of the effects of such strategies given that considerable levels of unmet need remain. I conclude that more attention should be paid to the gatekeeper role of GPs and how their actions in different social contexts may result in inequalities in service provision to low income patients and outcomes of care.

"Wait till it's serious:" health care costs and urban survival strategies of low income groups in Christchurch

AIM

To examine the 'survival' strategies adopted by lower income groups seeking to cope with the costs of primary care.

METHOD

Two surveys, one of the health and health service concerns of clients of an inner city voluntary welfare agency, and another of how 114 general practitioner (GP) surgeries in Christchurch aided patients in financial distress, were conducted in October-December, 1997.

RESULTS

Patients adopted a variety of strategies, both active and passive, with delays in obtaining medications and seeking financial help from GPs being the most common. Although less important, high rates of switching GPs occurred. There was evidence of geographical variation in the strategies adopted by patients and practices as well as of the effects of such strategies given that considerable levels of unmet need remain.

CONCLUSION

The results suggest that new primary care initiatives are required to meet the health needs of disadvantaged populations.

Impairment of olfactory identification in obsessive-compulsive disorder

BACKGROUND

Olfactory identification ability has been associated with processing in the orbitofrontal cortex (OFC), an area that has been implicated in the pathophysiology of obsessive-compulsive disorder (OCD). Although olfactory sensitivity is normal in patients with OCD, no study has investigated olfactory identification in this disorder.

METHODS

A group of 20 subjects with OCD and 23 age- and education-matched controls performed a standardized test of olfactory identification. They also performed computerized tests of spatial memory span, spatial working memory and spatial recognition memory that have been shown previously to be sensitive to cognitive deficits in patients with OCD.

RESULTS

Performance on the olfactory identification task, spatial recognition task and spatial span task was significantly worse in the OCD group than controls.

CONCLUSIONS

While impairment in spatial cognition is consistent with previous studies of OCD, its significance for brain-behaviour models of OCD is unclear. However, the finding of abnormal olfactory identification in patients with OCD is consistent with the hypothesis that there is a disruption to processing at the level of the OFC in the disorder.

Recurrence rates of ischial sores in para- and tetraplegics treated with hamstring flaps: an 8-year study

We have collected data on the second follow-up of 27 patients who underwent musculocutaneous flap closure of their ischial pressure sores. Thirty-seven ulcers were operated on between 1988 and 1993 using the V-Y advancement hamstring musculocutaneous island flap. At the initial follow-up (mean = 20 months) in 1993, despite 33% of patients having had recurrent ulcers and 14.8% having undergone re-advancements, only 14% of patients had non-healing ulcers. In 1997, follow-up period ranged from 18 to 90 months, with a mean of 62 months. Four patients were lost to follow-up resulting in 23 patients (n = 23) for the current study. Nine patients were tetraplegic and the remaining 14 were paraplegic. Four of the 23 patients had died at follow-up therefore making the number of living patients 19 (n = 19). The total number of ulcers operated on in the current study was 29 (U = 29). Overall, ulcer and patient recurrence rates were 41.4% and 47.8% respectively. Despite this, 89.5% of patients had intact flaps at the time of follow-up. We recommend the use of the hamstring V-Y musculocutaneous flap as a reliable and safe reconstructive modality in the management of ischial pressure sores and by identifying the group of patients susceptible to ulcer recurrence we have proposed a protocol for their long-term follow-up.

Flumazenil in drug overdose: randomized, placebo-controlled study to assess cost effectiveness

OBJECTIVE

To investigate cost effectiveness of administration of flumazenil to patients presenting with suspected acute drug overdose.

DESIGN

Double-blind, prospective, placebo-controlled randomized study.

SETTING

University teaching hospital.

PATIENTS

Forty-three adults presenting with suspected drug overdose and having a Glasgow Coma Scale (GCS) score of <13. Patients with known benzodiazepine/tricyclic ingestion were excluded.

INTERVENTIONS

Intravenous administration of flumazenil (up to 2 mg) or placebo.

MEASUREMENTS AND MAIN RESULTS

Individual patient costs were assessed and data aggregated for each treatment group. Major diagnostic and therapeutic interventions were recorded and between group comparisons performed. Clinical response to study drug administration was assessed by obtaining pre- and post-drug GCS scores and observation of the patient for at least 180 mins for signs of resedation. Aggregate cost or number of major diagnostic and therapeutic interventions were not different between groups. Patients randomized to the flumazenil group showed a marked increase in GCS score (7.4 to 11.8) compared with those in the placebo group (8.2 to 8.6).

CONCLUSION

Use of flumazenil in intentional drug overdose of unknown etiology is not cost effective.

Association between seasonal affective disorder and the 5-HT2A promoter polymorphism, -1438G/A

Genes involved in serotonin metabolism are good candidates for the pathogenesis of seasonal affective disorder (SAD). A functional variant in the serotonin transporter promoter, 5-HTTLPR, has recently been shown to be associated with SAD and seasonality. The purpose of this study was to determine whether -1438G/A, a polymorphism in the 5-HT2A promoter, is associated with SAD and seasonality, and whether it has additive effects with 5-HTTLPR on seasonality. Sixty-seven individuals with SAD and 69 normal volunteers, all screened with the SCID and diagnosed according to DSM-III-R criteria, were genotyped for the -1 438G/A 5-HT2A promoter polymorphism. All had been previously genotyped for 5-HTTLPR and had been assessed for seasonality by the Global Seasonality Scale. There was a significant increase in the frequency of the -1438A variant allele of the 5-HT2A promoter polymorphism in SAD patients (0.47) compared to matched controls (0.36) (P < 0.01). The difference in genotype distribution was also significant (P < 0.05). We found no association between the -1438G/A polymorphism and seasonality scores, and there was no additive effect with 5-HTTLPR on seasonality. In conclusion, we have shown that the -1438G/A 5-HT2A promoter variant is associated with SAD but not with seasonality. We suggest that the association may instead be with the depressive symptoms of SAD. However, these results should be treated with caution until replicated because of the possibility of false-positive findings in case-control association studies.

Full-body interface pressure testing as a method for performance evaluation of clinical support surfaces

A method for evaluating the performance of clinical support surfaces is required by designers in their efforts to produce better clinical support surfaces that will reduce the incidence of pressure ulcers. In this study, a Pressure Index (P(index)) is defined which is derived from an analytical equation used to evaluate the average interface pressure, the peak pressure, the magnitude of the peak pressure, and the number of peak pressures on the entire body. The type of subjects needed to represent a population of users as well as the head of bed elevations necessary to simulate clinical applications were integrated with the P(index) to create a single-value mean pressure index which can be used to evaluate any type of surface. To determine the accuracy and repeatability of the mean pressure index, three surfaces (a standard hospital innerspring, a replacement foam mattress, and a low-airloss surface) were tested and evaluated using this method. The low airloss performed the best and the standard innerspring clearly performed the worst (p < 0.0001). The method appeared to accurately and reproducibly predict the relative performance of the three surfaces in reducing pressure.

Acute renal failure in infants, children and adults

Acute renal failure (ARF) occurs in many critically ill patients regardless of age. A combination of events often seen in critical care settings, including shock, sepsis, hypoxia, and the use of potentially nephrotoxic medications, combine to make ARF an ongoing and important management issue in critical care medicine. Since the events leading to the development of ARF differ in infants, children, adults, and the elderly, the pathophysiology, clinical features, and treatment modalities do indeed have remarkable similarities among the different age groups.

A comparison of intensive care unit utilization in Alberta and western Massachusetts

OBJECTIVE

To analyze differences in intensive care unit (ICU) utilization between a Canadian province and a U.S. area.

DESIGN

Retrospective data analysis of hospital discharge data and existing data from an international study of severity of illness in ICU patients.

SETTING

Administrative data for the province of Alberta and the four counties of western Massachusetts for the years 1990 to 1991 were used. Detailed data on consecutive ICU admissions from two Alberta hospitals, one western Massachusetts hospital, and 24 other U.S. hospitals for 3 months in 1991 were used.

MEASUREMENTS AND MAIN RESULTS

ICU use and hospital mortality rates were compared for 50,030 hospital admissions divided into 11 patient groups. ICU days per million population were two to three times as great in western Massachusetts as in Alberta. The primary reason was higher ICU incidence (percent of hospitalized patients treated in the ICU) rather than a difference in hospital admission rate or length of ICU stay. ICU incidence in western Massachusetts was significantly higher in ten of 11 patient groups--for the coronary bypass surgery group, there was no difference. The hospital mortality rate in western Massachusetts was similar to, or higher than, the mortality rate in Alberta. In Alberta, a much higher proportion of ICU patients received mechanical ventilation. For elective surgery patients, the ICU severity of illness was lower in western Massachusetts and in other U.S. hospitals than in Alberta.

CONCLUSIONS

Western Massachusetts hospitalized patients are more likely to be treated in an ICU than are similar patients in Alberta. There is no evidence that the greater ICU utilization in western Massachusetts led to a lower hospital mortality rate.

A physician's perspective on capitation

Change is not on the horizon; it is already here. Capitation is only the latest form of competition with which we physicians have dealt through high school, college, medical school, postgraduate training, and even entry into practice. Capitation is a reality. It is here to stay. It will not disappear. It is a concept that must be understood, embraced, and managed to ensure financial survival. Physicians face issues of life and death on a daily basis. It is not too much for them to handle capitation.

V-Y advancement hamstring myocutaneous island flap repair of ischial pressure ulcers

Thirty-seven ischial pressure ulcers were repaired in 27 patients (eight quadriplegic, 19 paraplegic) between 1988-1993 using the V-Y advancement hamstring myocutaneous island flap. Twenty-one ulcers (57%) arose de novo and 16 were recurrent, with five patients having bilateral ulcers. The average duration of the ulcer was 5 months (range 1-30). All ulcers extended through the deep fascia (clinical grade IV), with the average diameter being 4.7 cm (range 2-10). There were four major flap complications (11%). All but one of the ulcers healed at discharge (97%). Mean follow up was 20 months (range 5-54) in 21 patients (78%), with six patients being lost to follow up. Seven of the 21 (33%) patients developed recurrent ulcers, with four of these having flap re-advancement with successful healing, and one patient having two re-advancements. Overall, 18 of the 21 (86%) patients with follow up had healed ulcers at time of follow up. The V-Y advancement hamstring myocutaneous island flap is versatile, reliable, easy to perform, has few complications, and can be re-advanced in the event of recurrence.

Cost containment: the Americas. Canada

Resources allocated for health care in Canada are about to be decreased. In recent years, the Canadian healthcare system has been consuming a progressively greater share of the country's gross domestic product. Due to recession, less revenue is available for health care. The need to contain and limit national healthcare spending has begun to affect resource allocation in Canadian ICUs. Increasing efficiency and reducing inappropriate use may not be enough to contain costs. More difficult decisions need to be made.

Amputations in the surgical budget

AIM

To describe the extent and distribution of in patient costs of nontraumatic lower limb amputations and to identify areas of high cost as a basis for cost saving strategic planning.

METHODS

Retrospective review of 134 consecutive admissions resulting in lower limb amputations for reasons other than trauma over a 33 month period. General surgical and orthopaedic costs were compared. More detailed cost distribution analysis was then conducted for a group of general surgical amputees corroborating data from the resource utilisation system, Otago surgical audit and patient records.

RESULTS

The mean cost of admission for nontraumatic lower limb amputations performed by general surgeons was $11,342 (median $21,439 range $144-$43,022) and was significantly more expensive than orthopaedic amputations, mean $2318 (median $6277 range $307-$13,907) p < 0.001. Of general surgical patients, 38.7% had diabetes and these accounted for 36.1% of total costs. Most amputations (73.9%) in diabetics were of the minor type compared with 29.0% in the nondiabetic group (p < 0.001). Ward costs accounted for the largest proportion of total cost 55.6% (95% CI 45.1, 66.0). For major amputees 40% (95% CI 31.4, 48.1) of in-hospital time was used for rehabilitation.

CONCLUSION

Nontraumatic amputations are costly. Diabetics, having mainly minor amputations, account for a disproportionate amount of the cost. Length of hospital stay is the most important determinant of cost, much of which is spent on rehabilitation. A case is made for early definitive surgery and a greater use of community based services and low cost centres in rehabilitation.