Results of Randomized Controlled Trials of Platelet-Rich Plasma in Lower-Extremity Tendinopathy Are Not Influenced by Industry Sponsorship.

PURPOSE: To determine whether industry affiliation influences the results of randomized controlled trials (RCTs) studying the use of platelet-rich plasma (PRP) for the treatment of patellar or Achilles tendinopathy. METHODS: The PubMed, Scopus, Cochrane, and MEDLINE databases were searched in July 2023 for RCTs investigating PRP for the treatment of patellar or Achilles tendinopathy published between 2009 and July 2023. Industry affiliation was determined by analyzing each study's funding or conflict-of-interest section. Author disclosures were searched in the American Academy of Orthopaedic Surgeons disclosure database and the Centers for Medicare & Medicaid Services open payments database. An industry-affiliated (IA) designation was given if an author had a relevant disclosure or if the company that funded the study manufactured PRP. Otherwise, a non-industry-affiliated (NIA) designation was given. Fisher exact analysis was used to determine whether PRP had a favorable effect, no significant effect, or an unfavorable effect on outcome. RESULTS: Analysis was performed on 22 studies (10 IA and 12 NIA), with 17 studies (77.3%) reporting a conflict of interest or funding for the research, 4 (18.2%) reporting no conflict of interest, and 1 (4.5%) with no reporting. Of the 22 included studies, 8 (36.4%) reported favorable outcomes regarding PRP use and 14 (63.6%) reported no significant effect. Favorable outcomes were found in 4 of the 10 IA studies (40.0%), whereas no significant effect was reported in 6 (60.0%). The 12 NIA studies included 4 (33.3%) with favorable results and 8 (66.7%) with no significant effect. The comparison between industry affiliation and results reported was not statistically significant (P > .999). CONCLUSIONS: The results of RCTs evaluating the use of PRP in lower-extremity tendinopathy were not influenced by industry sponsorship. CLINICAL RELEVANCE: Most biomedical research is funded through industry sponsorship. Although this relation is necessary as technologies are developed, it is important to scrutinize studies for evidence of industry bias to understand how this bias may be affecting study results published in the literature.

Use of a rapid triage assessment tool to discriminate the need for hospitalisation in patients with severe COVID-19 infection presenting to an outpatient clinic: a single-centre, prospective cohort study.

OBJECTIVES: The WHO designated individuals with low oxygen saturation, SpO2<94%, as severe SARS-CoV2 infection (COVID-19) and recommendations to seek care in a hospital setting were advised. A rapid, office-based method to select patients with severe COVID-19 who need intensive care was necessary during the peak of the pandemic. DESIGN, SETTING AND PARTICIPANTS: This is a prospective cohort study of patients with confirmed severe COVID-19 between September 2020 and April 2021. OUTCOME MEASURES AND ANALYSIS: Oxygen saturation was obtained at rest (SpO2r), following exertion from a 20 m walk test (SpO2e), and the difference was calculated (SpO2Δ). Radiographs and laboratory values were obtained and recorded. Logistic regression models were used to determine variables associated with hospitalisation. A lung injury score was used to quantify pulmonary involvement. RESULTS: Out of 103 patients enrolled with severe COVID-19 infection, 19 (18.4%) were admitted to the hospital (no deaths). Patients managed as outpatients had a standard treatment protocol. The SpO2Δ and SpO2e were associated with hospitalisation (p<0.005) while SpO2r was no different between non-hospitalised and hospitalised patients (90.7%±2.7% vs 90.8%±2.3%, p=0.87). By contrast, exertional SpO2e was significantly different between non-hospitalised and hospitalised (87.3%±2.6% vs 84.4%±3.4%, p=0.0005). The mean lung injury score was 11.0±3.5 (18-point scale) and did not discriminate against those who would need hospitalisation. Lower lung fields were significantly more involved than the upper (p<0.0001). All patients had elevated biomarkers of inflammation, C reactive protein (CRP) median 82.5 IQR (43-128.6) mg/L and evidence of elevated liver enzymes. A logistic regression model was constructed including SpO2Δ, CRP and alanine aminotransferase to predict hospitalisation. Only SpO2Δ was significant, p=0.012, 95% CI (1.128 to 2.704) and correctly classified 85.71% of patients who could remain at home or would need to receive treatment in the hospital. CONCLUSION: An office-based, 20 m walk test can help diverge patients with severe COVID-19 who need escalated care. Further, an aggressive standardised treatment protocol can be used to successfully manage patients outside of hospitals despite having severe COVID-19.

Sexually transmitted infections manifesting as proctitis.

There is a rising incidence of several sexually transmitted infections (STIs), many of which can present with proctitis. Causative organisms include Neisseria gonorrhoeae, Chlamydia trachomatis, herpes simplex virus, Treponema pallidum (syphilis), Giardia lamblia (giardiasis) and Entamoeba histolytica (amoebiasis). This paper outlines important clinical discriminators and key investigations to distinguish these organisms from non-infective pathology that include inflammatory bowel disease, solitary rectal ulcer syndrome and Behçet's syndrome. Management of these infections is described and suggestions are made for successful gastroenterology clinical consultation when an STI is suspected.

Developing an endoscopic mucosal resection service in a district general hospital.

OBJECTIVE: To describe the implementation of a formal single-operator led endoscopic mucosal resection (EMR) service in a district general hospital, and the effect on patient outcome of this service development. DESIGN: Prospective audit during initiation and subsequent development of EMR service. SETTING: District general hospital. PATIENTS: All patients referred to EMR service between 1 January 2008 and 31 December 2011. INTERVENTIONS: Nil in addition to clinical care. MAIN OUTCOMES MEASURED: The number of EMRs per year including polyp size and histology, recurrence of polyp tissue at 3 months following EMR, and complications including early/delayed bleeding and perforation. RESULTS: Following service implementation, the number of EMRs rose from 11 in 2008 to 35 in 2011, with the number of large polyps (>30 mm) rising from four in 2008 to 24 in 2011. Recurrent or residual adenomatous tissue fell from 75% in 2008 to 4.76% in 2011. Only one perforation occurred over the 4 years (0.8% perforation rate: 1 in 120 polypectomies). A reduction in surgical intervention for adenomatous polyp removal was observed during the audit period. CONCLUSIONS: Professional engagement and support by medical, surgical and nursing members of the endoscopy team promoted development of skill and confidence in EMR. Exposure to higher volumes of EMR procedures allowed successful removal of larger lesions, while maintained patient safety and reduced the need for surgical removal of benign polyps.

Pseudomonas sax genes overcome aliphatic isothiocyanate-mediated non-host resistance in Arabidopsis.

Most plant-microbe interactions do not result in disease; natural products restrict non-host pathogens. We found that sulforaphane (4-methylsulfinylbutyl isothiocyanate), a natural product derived from aliphatic glucosinolates, inhibits growth in Arabidopsis of non-host Pseudomonas bacteria in planta. Multiple sax genes (saxCAB/F/D/G) were identified in Pseudomonas species virulent on Arabidopsis. These sax genes are required to overwhelm isothiocyanate-based defenses and facilitate a disease outcome, especially in the young leaves critical for plant survival. Introduction of saxCAB genes into non-host strains enabled them to overcome these Arabidopsis defenses. Our study shows that aliphatic isothiocyanates, previously shown to limit damage by herbivores, are also crucial, robust, and developmentally regulated defenses that underpin non-host resistance in the Arabidopsis-Pseudomonas pathosystem.

A randomized controlled trial investigation of a non-stimulant in attention deficit hyperactivity disorder (ACTION): rationale and design.

BACKGROUND: The ACTION study (Attention deficit hyperactivity disorder Controlled Trial Investigation Of a Non-stimulant) is a multi-center, double-blind, randomized cross-over trial of the non-stimulant medication, Atomoxetine, in children and adolescents with attention deficit hyperactivity disorder (ADHD). The primary aims are to examine the efficacy of atomoxetine for improving cognition and emotional function in ADHD and whether any improvements in these outcomes are more pronounced in participants with comorbid anxiety; and to determine if changes in these outcomes after atomoxetine are more reliable than changes in diagnostic symptoms of ADHD. This manuscript will describe the methodology and rationale for the ACTION study. METHODS: Children and adolescents aged 6 - 17 y with ADHD will be enrolled. Clinical interview and validated scales will be used to confirm diagnosis and screen for exclusion criteria, which include concurrent stimulant use, and comorbid psychiatric or neurological conditions other than anxiety. Three assessment sessions will be conducted over the 13-week study period: Session 1 (Baseline, pre-treatment), Session 2 (six weeks, atomoxetine or placebo), and Session 3 (13 weeks, cross-over after one-week washout period). The standardized touch-screen battery, "IntegNeuro™", will be used to assess cognitive and emotional function. The primary measure of response will be symptom ratings, while quality of life will be a secondary outcome. Logistic regression will be used to determine predictors of treatment response, while repeated measures of analysis will determine any differences in effect of atomoxetine and placebo. RESULTS: The methodology for the ACTION study has been detailed. CONCLUSIONS: The ACTION study is the first controlled trial to investigate the efficacy of atomoxetine using objective cognitive and emotional function markers, and whether these objective measures predict outcomes with atomoxetine in ADHD with and without comorbid anxiety. First enrollment was in March 2008. The outcomes of this study will be a significant step towards a 'personalized medicine' (and therefore a more efficient) approach to ADHD treatment. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry ANZCTRN12607000535471.

Heterologous expression and characterization of recombinant OsCDR1, a rice aspartic proteinase involved in disease resistance.

The Oryza sativa constitutive disease resistance 1 (OsCDR1) gene product is an aspartic proteinase that has been implicated in disease resistance signaling. This apoplastic enzyme is a member of the group of 'atypical' plant aspartic proteinases. Recombinant OsCDR1 expressed in Escherichia coli exhibited protease activity against succinylated-casein substrate. Inactivating the enzyme through modification of an aspartate residue present in the deduced active site completely abolished its proteinase activity. Infiltration of the OsCDR1 fusion protein into leaves of Arabidopsis plants induced PR2 transcripts in both the infiltrated leaf (primary) and in non-treated secondary leaves while the inactive recombinant protein failed to induce either local or systemic PR2. These findings demonstrate that OsCDR1 is capable of inducing systemic defense responses in plants.

Using brain-based cognitive measures to support clinical decisions in ADHD.

Measures of cognition support diagnostic and treatment decisions in attention deficit hyperactivity disorder. We used an integrative neuroscience framework to assess cognition and associated brain-function correlates in large attention deficit hyperactivity disorder and healthy groups. Matched groups of 175 attention deficit hyperactivity disorder children/adolescents and 175 healthy control subjects were assessed clinically, with the touch screen-based cognitive assessment battery "IntegNeuro" (Brain Resource Ltd., Sydney, Australia) and the "LabNeuro" (Brain Resource Ltd., Sydney, Australia) platform for psychophysiologic recordings of brain function and body arousal. IntegNeuro continuous performance task measures of sustained attention classified 68% of attention deficit hyperactivity disorder patients with 76% specificity, consistent with previous reports. Our additional cognitive measures of impulsivity, intrusive errors, inhibition, and response variability improved sensitivity to 88%, and specificity to 91%. Positive predictive power was 96%, and negative predictive power, 88%. These metrics were stable across attention deficit hyperactivity disorder subtypes and age. Consistent with their brain-based validity, cognitive measures were correlated with corresponding brain-function and body-arousal measures. We propose a combination of candidate cognitive "markers" that define a signature for attention deficit hyperactivity disorder: "sustained attention," "impulsivity," "inhibition," "intrusions," and "response variability." These markers offer a frame of reference to support diagnostic and treatment decisions, and an objective benchmark for monitoring outcomes of interventions.

Clinical signs, magnetic resonance imaging findings and outcome in 77 cats with vestibular disease: a retrospective study.

Medical records of 77 cats that had clinical signs of vestibular disease and magnetic resonance imaging (MRI) of the head were reviewed retrospectively. The aetiological, clinical and MRI characteristics were described and evaluated for a relationship with patient outcome. Forty cats (52%) had signs of central vestibular dysfunction (CVD), which was part of a multifocal disease in 17 cats (43%). The most frequent causes of CVD were inflammatory conditions (18 cats; 45%), including bacterial inflammation as an intracranial extension of otitis interna (five cats; 13%), feline infectious peritonitis (three cats; 8%) and toxoplasmosis (two cats; 5%). Neoplasia (12 cats; 30%) and vascular disease (four cats; 10%) were respectively the second and the third most frequent causes of CVD. Thiamine deficiency was diagnosed in one cat based on MRI findings and improvement following vitamin B(1) supplementation. Of 37 cats (48%) with peripheral vestibular dysfunction (PVD), idiopathic vestibular syndrome (IVS) was suspected in 16 (43%) and otitis media/interna was suspected in 16 (43%). Within the group of cats with evident MRI lesions, the location of the imaged lesions agreed with the clinical classification of vestibular dysfunction in 52/55 (95%) cats. Most of the cats (nine cases; 56%) with presumed IVS had rapid and complete recovery of their clinical signs. As most of these cats presented with progressive clinical signs over 3 weeks they were classified as having 'atypical' IVS to differentiate them from cats with the typical non-progressive IVS. No underlying systemic diseases were documented in any of these cases. Statistically significant predictors of survival included neurolocalisation (central or peripheral vestibular system), age and gender. No difference in survival was observed between cats with presumed idiopathic peripheral syndrome and cats with otitis media/interna.

Overexpression of rice (Oryza sativa L.) OsCDR1 leads to constitutive activation of defense responses in rice and Arabidopsis.

Plant aspartic proteases (AP) play key roles in the regulation of biological processes, such as the recognition of pathogens and pests and the induction of effective defense responses. A large number of AP (>400) have been identified in silico in the rice genome. None have previously been isolated and functionally characterized for their involvement in disease resistance. We describe here the isolation and characterization of a gene (OsCDR1) from rice which encodes a predicted aspartate protease. Expression of OsCDR1 was activated upon treatments with benzothiadiazole and salicylic acid, which are signal molecules in plant disease resistance responses. Ectopic expression of OsCDR1 in Arabidopsis and rice conferred enhanced resistance against bacterial and fungal pathogens. The enhanced disease resistance observed in transgenic plants was correlated with induction of pathogenesis-related gene expression and was shown by mutational analysis to be dependent on AP activity of the transgene-encoded product. OsCDR1 accumulates in intercellular fluids (IF) in transgenic plants. Infiltration of IF from transgenic Arabidopsis plants into leaves of wild-type (WT) Arabidopsis induced the systemic defense response. These results demonstrate the conservation of CDR1 function between rice and Arabidopsis during the disease resistance response.

Abscisic acid has a key role in modulating diverse plant-pathogen interactions.

We isolated an activation-tagged Arabidopsis (Arabidopsis thaliana) line, constitutive disease susceptibility2-1D (cds2-1D), that showed enhanced bacterial growth when challenged with various Pseudomonas syringae strains. Systemic acquired resistance and systemic PATHOGENESIS-RELATED GENE1 induction were also compromised in cds2-1D. The T-DNA insertion adjacent to NINE-CIS-EPOXYCAROTENOID DIOXYGENASE5 (NCED5), one of six genes encoding the abscisic acid (ABA) biosynthetic enzyme NCED, caused a massive increase in transcript level and enhanced ABA levels >2-fold. Overexpression of NCED genes recreated the enhanced disease susceptibility phenotype. NCED2, NCED3, and NCED5 were induced, and ABA accumulated strongly following compatible P. syringae infection. The ABA biosynthetic mutant aba3-1 showed reduced susceptibility to virulent P. syringae, and ABA, whether through exogenous application or endogenous accumulation in response to mild water stress, resulted in increased bacterial growth following challenge with virulent P. syringae, indicating that ABA suppresses resistance to P. syringae. Likewise ABA accumulation also compromised resistance to the biotrophic oomycete Hyaloperonospora arabidopsis, whereas resistance to the fungus Alternaria brassicicola was enhanced in cds2-1D plants and compromised in aba3-1 plants, indicating that ABA promotes resistance to this necrotroph. Comparison of the accumulation of salicylic acid and jasmonic acid in the wild type, cds2-1D, and aba3-1 plants challenged with P. syringae showed that ABA promotes jasmonic acid accumulation and exhibits a complex antagonistic relationship with salicylic acid. Our findings provide genetic evidence that the abiotic stress signal ABA also has profound roles in modulating diverse plant-pathogen interactions mediated at least in part by cross talk with the jasmonic acid and salicylic acid biotic stress signal pathways.

The structure of "defective in induced resistance" protein of Arabidopsis thaliana, DIR1, reveals a new type of lipid transfer protein.

Screening of transfer DNA (tDNA) tagged lines of Arabidopsis thaliana for mutants defective in systemic acquired resistance led to the characterization of dir1-1 (defective in induced resistance [systemic acquired resistance, SAR]) mutant. It has been suggested that the protein encoded by the dir1 gene, i.e., DIR1, is involved in the long distance signaling associated with SAR. DIR1 displays the cysteine signature of lipid transfer proteins, suggesting that the systemic signal could be lipid molecules. However, previous studies have shown that this signature is not sufficient to define a lipid transfer protein, i.e., a protein capable of binding lipids. In this context, the lipid binding properties and the structure of a DIR1-lipid complex were both determined by fluorescence and X-ray diffraction. DIR1 is able to bind with high affinity two monoacylated phospholipids (dissociation constant in the nanomolar range), mainly lysophosphatidyl cholines, side-by-side in a large internal tunnel. Although DIR1 shares some structural and lipid binding properties with plant LTP2, it displays some specific features that define DIR1 as a new type of plant lipid transfer protein. The signaling function associated with DIR1 may be related to a specific lipid transport that needs to be characterized and to an additional mechanism of recognition by a putative receptor, as the structure displays on the surface the characteristic PxxP structural motif reminiscent of SH3 domain signaling pathways.

Event-related wave activity in the EEG provides new marker of ADHD.

OBJECTIVE: This study examines the utility of new measures of event-related spatio-temporal waves in the EEG as a marker of ADHD, previously shown to be closely related to the P3 ERP in an adult sample. METHODS: Wave activity in the EEG was assessed during both an auditory Oddball and a visual continuous performance task (CPT) for an ADHD group ranging in age from 6 to 18 years and comprising mostly Combined and Inattentive subtypes, and for an age and gender matched control group. RESULTS: The ADHD subjects had less wave activity at low frequencies ( approximately 1 Hz) during both tasks. For auditory Oddball targets, this effect was shown to be related to smaller P3 ERP amplitudes. During CPT, the approximately 1 Hz wave activity in the ADHD subjects was inversely related to clinical and behavioral measures of hyperactivity and impulsivity. CPT wave activity at approximately 1 Hz was seen to "normalise" following treatment with stimulant medication. CONCLUSIONS: The results identify a deficit in low frequency wave activity as a new marker for ADHD associated with levels of hyperactivity and impulsivity. SIGNIFICANCE: The marker is evident across a range of tasks and may be specific to ADHD. While lower approximately 1 Hz activity partly accounts for reduced P3 ERPs in ADHD, the effect also arises for tasks that do not elicit a P3. Deficits in behavioral inhibition are hypothesized to arise from underlying dysregulation of cortical inhibition.

High-throughput quantitative luminescence assay of the growth in planta of Pseudomonas syringae chromosomally tagged with Photorhabdus luminescens luxCDABE.

Bioluminescent strains of the Arabidopsis thaliana pathogens Pseudomonas syringae pathovar (pv.) tomato and pv. maculicola were made by insertion of the luxCDABE operon from Photorhabdus luminescens into the P. syringae chromosome under the control of a constitutive promoter. Stable integration of luxCDABE did not affect bacterial fitness, growth in planta or disease outcome. Luminescence accurately and reliably reported bacterial growth in infected Arabidopsis leaves both with a fixed inoculum followed over time and with varying inocula assayed at a single time point. Furthermore, the bioluminescence assay could detect a small (1.3-fold) difference in bacterial growth between different plant genotypes with a precision comparable to that of the standard plate assay. Luminescence of luxCDABE-tagged P. syringae allows rapid and convenient quantification of bacterial growth without the tissue extraction, serial dilution, plating and manual scoring involved in standard assays of bacterial growth by colony formation in plate culture of samples from infected tissue. The utility of the bioluminescence assay was illustrated by surveying the 500-fold variation in growth of the universally virulent P. syringae pv. maculicola ES4326 among more than 100 Arabidopsis ecotypes and identification of two quantitative trait loci accounting for 48% and 16%, respectively, of the variance of basal resistance to P. syringae pv. tomato DC3000 in the Col-0 x Fl-1 F(2) population. Luminescence assay of bacteria chromosomally tagged with luxCDABE should greatly facilitate the genetic dissection of quantitative differences in gene-for-gene, basal and acquired disease resistance and other aspects of plant interactions with bacterial pathogens requiring high-throughput assays or large-scale quantitative screens.

Expression of a nitric oxide degrading enzyme induces a senescence programme in Arabidopsis.

Nitric oxide (NO) has been proposed to act as a factor delaying leaf senescence and fruit maturation in plants. Here we show that expression of a NO degrading dioxygenase (NOD) in Arabidopsis thaliana initiates a senescence-like phenotype, an effect that proved to be more pronounced in older than in younger leaves. This senescence phenotype was preceded by a massive switch in gene expression in which photosynthetic genes were down-regulated, whereas many senescence-associated genes (SAGs) and the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase gene ACS6 involved in ethylene synthesis were up-regulated. External fumigation of NOD plants with NO as well as environmental conditions known to stimulate endogenous NO production attenuated the induced senescence programme. For instance, both high light conditions and nitrate feeding reduced the senescence phenotype and attenuated the down-regulation of photosynthetic genes as well as the up-regulation of SAGs. Treatment of plants with the cytokinin 6-benzylaminopurin (BAP) reduced the down-regulation of photosynthesis, although it had no consistent effect on SAG expression. Metabolic changes during NOD-induced senescence comprehended increases in salicylic acid (SA) levels, accumulation of the phytoalexin camalexin and elevation of leaf gamma-tocopherol contents, all of which occurred during natural senescence in Arabidopsis leaves as well. Moreover, NO fumigation delayed the senescence process induced by darkening individual Arabidopsis Columbia-0 (Col-0) leaves. Our data thus support the notion that NO acts as a negative regulator of leaf senescence.

Crystallization of DIR1, a LTP2-like resistance signalling protein from Arabidopsis thaliana.

DIR1, a putative LTP2 protein from Arabidopsis thaliana implicated in systemic acquired resistance in planta, has been crystallized in space group P2(1)2(1)2(1) with one molecule per asymmetric unit. The crystals diffract to a resolution of 1.6 angstroms.

Multi-sectoral health promotion and public health: the role of evidence.

BACKGROUND: Evidence-informed health promotion and public health is an emerging and ever-changing theme in research and practice. A collaborative approach to gathering and applying evidence is crucial to implementing effective multi-sectoral health promotion and public health interventions for improved population outcomes. This paper presents an argument for the development of multi-sector evidence and discusses both facilitators and challenges to this process. METHODS: Sector-specific contacts familiar with decision-making processes were selected from referrals gained through academic, government and non-government networks and interviewed (in-person or via telephone) as part of a small scale study to scope the use of evidence within non-health sectors where decisions are likely to impact on public health. RESULTS: The views gathered are preliminary, and this analysis would benefit from more extensive consultation. Nonetheless, information gathered from the interviews and literature search provide valuable insights into evidence-related decision-making paradigms which demonstrate similarities with, and differences from, those found in the health sector. CONCLUSIONS: Decisions in health promotion and public may benefit from consideration of the ways in which disciplines and sectors can work together to inform policy and practice.

Systemic immunity.

Systemic acquired resistance (SAR) provides enhanced, long-lasting systemic immunity to secondary infection by a range of biotrophic, hemibiotrophic and necrotrophic pathogens that have diverse modes of infection. Considerable effort has focussed on the conserved central positive regulator of SAR, NON-EXPRESSOR OF PATHOGENESIS-RELATED1 (NPR1), and its control by changes in cellular redox potential. Recently, genetic and genomic approaches have highlighted a critical role for nucleocytoplasmic communication and protein secretion in establishing effective systemic immunity. Identification of the mobile signals and the mechanisms by which they are perceived in distal tissues remains challenging, but emerging evidence suggests that signal translocation uses lipid-derived (possibly jasmonate-based) signals and lipid-binding chaperones. Furthermore, the demonstration that autophagy interdicts and inactivates a systemic cell death signal adds further complexity to elucidating how mobile signals are decoded and transduced for effective immunity.

Distractibility in AD/HD predominantly inattentive and combined subtypes: the P3a ERP component, heart rate and performance.

The current study aimed to investigate whether children and adolescents diagnosed with Attention Deficit/Hyperactivity Disorder Predominantly Inattentive (AD/HD-in; Child n = 24, Adolescent n = 33) and Combined (AD/HD-com; Child n = 30, Adolescent n = 42) subtypes were more distractible than controls (Child n = 54; Adolescents n = 75), by assessing event-related potential (ERP), performance and peripheral arousal measures. All AD/HD groups displayed smaller amplitudes and/or shorter latencies of the P3a ERP component - thought to reflect involuntary attention switching - following task-deviant novel stimuli (checkerboard patterns) embedded in a Working Memory (WM) task. The P3a results suggested that both AD/HD-in and AD/HD-com subtypes ineffectively evaluate deviant stimuli and are hence more "distractible". These abnormalities were most pronounced over the central areas. AD/HD groups did not display any abnormalities in averaged heart rate over the WM task, a measure of peripheral arousal. They did display abnormalities in performance measures from the task, but these were unrelated to P3a abnormalities. AD/HD groups also displayed a number of deficits on Switching of Attention and Verbal Memory tasks, however, the pattern of abnormality mostly reflected general cognitive deficits rather than resulting from distraction.