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Joanna Wardlaw

Publications and source records attributed to Joanna Wardlaw.

8 recordsLinked to original sources
PubMed2005

Influence of an early-onset age of type 1 diabetes on cerebral structure and cognitive function.

OBJECTIVE: Children who develop type 1 diabetes before age 7 years (early-onset diabetes; EOD) have comparatively poorer cognitive abilities. Whether this relates to psychosocial consequences of chronic illness or organic factors related to diabetes and its complications remains unresolved. We hypothesized that if differences in neuroradiological structure and cognitive ability coexisted in those who had EOD, then an organic component to their etiology was likely. RESEARCH DESIGN AND METHODS: A cohort of 71 young adults with long-duration type 1 diabetes diagnosed during childhood or adolescence participated in a cross-sectional evaluation of cognitive ability (neuropsychological test battery) and brain structure (magnetic resonance imaging). Diabetes onset age, preceding severe hypoglycemia exposure, retinopathy status, and diabetes duration were examined as potential correlates of cognitive and neuroradiological differences. No participants had previous neuropsychological pathology. RESULTS: In EOD participants (n = 26), current intellectual ability (Wechsler Adult Intelligence Scale-Revised performance IQ; P = 0.03) and information processing ability (Choice Reaction Time; P = 0.006) were comparatively poorer than was observed in those with later- onset diabetes (n = 45). Furthermore, lateral ventricular volumes were 37% greater (P = 0.002) and ventricular atrophy was more prevalent (61 vs. 20%; P = 0.01) in the EOD group than in those who had later-onset type 1 diabetes. CONCLUSIONS: An early childhood onset of type 1 diabetes was associated with mild central brain atrophy and significant differences in intellectual performance in adulthood, implying that neurodevelopment may be adversely affected by EOD. The differences observed in brain structure support an organic contribution to their etiology but do not exclude a coexistent contribution of psychosocial factors.

Adult↗
PubMed2004

Cost-effectiveness of thrombolysis with recombinant tissue plasminogen activator for acute ischemic stroke assessed by a model based on UK NHS costs.

BACKGROUND AND PURPOSE: Thrombolytic therapy is licensed for use in highly selected patients with acute ischemic stroke. We aimed to model the health economic impact of limited use of thrombolytic therapy and to assess whether it was likely to be cost-effective when used more widely in the UK National Health Service (NHS). METHODS: The authors formed a discussion panel to develop the decision-analysis model of acute stroke care. It consisted of Markov state-transition processes, with probabilities of different health states determined by certain key variables. The range of estimates of efficacy of recombinant tissue plasminogen activator (rt-PA) was taken from an update to a Cochrane systematic review of randomized trials of thrombolysis. Data on outcome after stroke were taken from our hospital-based stroke register, supplemented by data derived from relevant literature sources. RESULTS: The model suggested that compared with standard care, if eligible patients were treated with rt-PA up to 6 hours, there was a 78% probability of a gain in quality-adjusted survival during the first year, at a cost of pound 13 581 per quality-adjusted life-year (QALY) gained. Over a lifetime, rt-PA was associated with cost-savings of pound 96 565 per QALY. However, the estimates were imprecise and highly susceptible to the assumptions used in the economic model; under several plausible assumptions, rt-PA was much less cost-effective than standard care, and under others, a great deal more cost-effective. CONCLUSIONS: The estimates of effectiveness and cost-effectiveness were imprecise. Although the benefits appeared promising, the data did not support the widespread use of thrombolytic therapy outside the terms of the current restricted license in routine clinical practice in the NHS. There is a case for new large-scale randomized trials comparing thrombolytic therapy with control up to 6 hours to determine more precisely the effects of rt-PA on short-term and long-term survival and its cost-effectiveness when used in a wider range of patients.

Acute Disease↗
PubMed2004

Changes in arterial oxygen saturation before and after enteral feeding tube insertion in dysphagic stroke patients.

OBJECTIVE: to determine whether insertion of nasogastric or percutaneous endoscopic gastrostomy feeding tubes is associated with hypoxaemia. METHODS: dysphagic stroke patients had their arterial oxygen saturation measured by pulse oximetry continuously for 10 minutes before, during and after tube insertion. RESULTS: in 14 patients nasogastric tube insertion had little effect on oxygen saturation. Six patients maintained oxygen saturation during percutaneous endoscopic gastrostomy insertion (whilst on 2 litres oxygen/min) but had a significantly lower median oxygen saturation (P = 0.03) after the procedure (when oxygen was discontinued) and four of these had oxygen saturation of < or =90%. CONCLUSIONS: in this small group of stroke patients, difficult insertions of nasogastric and percutaneous endoscopic gastrostomy tubes were associated with moderate hypoxaemia. Clinicians should be aware of the potential impact of tube insertion and ensure patients are appropriately monitored and if necessary receive supplemental oxygen, after as well as during the procedure.

Aged↗
PubMed2003

Stroke.

Stroke is a major public-health burden worldwide. Prevention programmes are essential to reduce the incidence of stroke and to prevent the all but inevitable stroke epidemic, which will hit less developed countries particularly hard as their populations age and adopt lifestyles of the more developed countries. Efficient, effective, and rapid diagnosis of stroke and transient ischaemic attack is crucial. The diagnosis of the exact type and cause of stroke, which requires brain imaging as well as traditional clinical skills, is also important when it will influence management. The treatment of acute stroke, the prevention and management of the many complications of stroke, and the prevention of recurrent stroke and other serious vascular events are all improving rapidly. However, stroke management will only be most effective when delivered in the context of an organised, expert, educated, and enthusiastic stroke service that can react quickly to the needs of patients at all stages from onset to recovery.

Acute Disease↗
PubMed2003

Induced hyperammonemia alters neuropsychology, brain MR spectroscopy and magnetization transfer in cirrhosis.

Hyperammonemia is a universal finding after gastrointestinal hemorrhage in cirrhosis. We administered an oral amino acid solution mimicking the hemoglobin molecule to examine neuropsychological changes, brain glutamine levels, and brain magnetization transfer ratio (MTR). Forty-eight metabolically stable patients with cirrhosis and no evidence of "overt" hepatic encephalopathy (HE) were randomized to receive 75 g of amino acid solution or placebo; measurements were performed before and 4 hours after administration. Neuropsychological tests included the Trails B Test, Digit Symbol Substitution Test, memory subtest of the Randt battery, and reaction time. Plasma was collected for ammonia and amino acid measurements, and brain metabolism was studied using proton magnetic resonance (MR) spectroscopy in the first 16 randomized patients. In 7 other patients, MTR was measured. A significant increase in ammonia levels was observed in the amino acid group (amino acid group, 76 +/- 7.3 to 121 +/- 6.4 micromol/L; placebo, 83 +/- 3.3 to 78 +/- 2.9 micromol/L; P <.001). Neuropsychological function improved significantly in the placebo group, but no significant change in neuropsychological function was observed in the amino acid group. Brain glutamate/glutamine (Glx)/creatine (Cr) ratio increased significantly in the amino acid group. MTR decreased significantly from 30 +/-2.9 to 23 +/- 4 (P <.01) after administration of the amino acid solution. In conclusion, an improvement in neuropsychological test results followed placebo, which was not observed in patients administered the amino acid solution. Induced hyperammonemia resulted in an increase in brain Glx/Cr ratio and a decrease in MTR, which may indicate an increase in brain water as the operative mechanism.

Amino Acids↗
PubMed2003

Cognitive ability and brain structure in type 1 diabetes: relation to microangiopathy and preceding severe hypoglycemia.

Type 1 diabetes is associated with chronic hyperglycemia and exposure to intermittent severe hypoglycemia. The long-term cerebral effects of these consequences of diabetes are ill defined. In this study, the history of preceding severe hypoglycemia and the presence of background retinopathy were examined in relation to cognitive ability (neuropsychological test battery) and brain structure (magnetic resonance imaging) in a cross-sectional evaluation of 74 young people with type 1 diabetes. Participants differed by their severe hypoglycemia exposure and degree of diabetic retinopathy and none had previous neuropsychological pathology. Severe hypoglycemia did not influence cognitive ability or brain structure. Background diabetic retinopathy was associated with small focal white-matter hyperintensities in the basal ganglia (33.3 vs. 4.7%, after correction for age, P = 0.005) and significant cognitive disadvantage, affecting fluid intelligence (P = 0.008, Eta(2) = 0.14), information processing (P = 0.001, Eta(2) = 0.22), and attention and concentration ability (P = 0.03, Eta(2) = 0.09). In conclusion, recurrent exposure to severe hypoglycemia alone in young people with type 1 diabetes had no detrimental impact on brain structure or function over the duration of diabetes examined. Chronic hyperglycemia (inferred by the presence of background diabetic retinopathy) may affect brain structure and function.

Adult↗