Increased γ oscillations during voluntary selection processes in adult patients with attention deficit/hyperactivity disorder.

Executive dysfunctions (regarding behavioural inhibition, decision making, flexibility or voluntary selection) rank among the core symptoms of attention deficit/hyperactivity disorder. Several studies demonstrated functional variations in patients with ADHD especially during response inhibition and flexibility. However, information about functional correlates of other aspects of executive functions such as voluntary selection processes is limited. A group of thirty adult patients with attention deficit/hyperactivity disorder (ADHD) and 30 healthy controls, matched for age and education, participated in the present study. Electrophysiological responses (event-related potentials, gamma oscillations) and behavioural data were acquired during the voluntary selection between various response alternatives. ADHD patients demonstrated increased responses in the gamma frequency band especially in frontal and fronto-central brain areas during voluntary response selection processes compared to healthy subjects. In addition, the error rate was increased in patients. Given that gamma-band responses have been related to GABAergic and glutamatergic responses these results may indicate accordant dysfunction in patients with ADHD.

Neural correlates (ERP/fMRI) of voluntary selection in adult ADHD patients.

Deficits in executive functions, e.g. voluntary selection, are considered central to the attention-deficit/hyperactivity disorder (ADHD). The aim of this simultaneous EEG/fMRI study was to examine associated neural correlates in ADHD patients. Patients with ADHD and healthy subjects performed an adapted go/nogo task including a voluntary selection condition allowing participants to freely decide, whether to press the response button. Electrophysiologically, response inhibition and voluntary selection led to fronto-central responses. The fMRI data revealed increased medial/lateral frontal and parietal activity during the voluntary selection task. Frontal brain responses were reduced in ADHD patients compared to controls during free responses, whereas parietal brain functions seemed to be unaffected. These results may indicate that selection processes are related to dysfunctions, predominantly in frontal brain regions in ADHD patients.

Less impairment on one portion of a driving-relevant psychomotor battery in buprenorphine-maintained than in methadone-maintained patients: results of a randomized clinical trial.

BACKGROUND: Cognitive impairment in drug-dependent patients under methadone maintenance treatment has been reported before. We assessed whether patients under buprenorphine, a partial mu-opioid agonist, perform better in cognitive tests measuring psychomotor performance as described in previous nonrandomized studies. METHODS: We performed a randomized clinical trial in 62 drug-dependent patients under either buprenorphine or methadone treatment. Sixteen patients dropped out of maintenance therapy, before the testing was performed, after 8 to 10 weeks of treatment. Several subtests of the Act & React Test System test battery were used measuring visual perception, selective attention, vigilance, reactivity, and stress tolerance. FINDINGS: Although there were no differences in cognitive function at baseline, patients under buprenorphine treatment showed partially better results in some of the domains tested. The used tests are relevant when assessing driving ability. There was a significant correlation between dose of buprenorphine and some test results. We also found a correlation between age and reaction time and between duration of opioid dependence and results in some subtests. INTERPRETATIONS (CONCLUSIONS): When comparing both treatments in drug dependent patients, buprenorphine produces partially less impairment on cognitive functions in some of the subtests of the psychomotor battery than methadone. This difference is specially relevant when it comes to driving ability and social functioning.

Complex segregation analysis of restless legs syndrome provides evidence for an autosomal dominant mode of inheritance in early age at onset families.

A strong familial component of restless legs syndrome (RLS) is known. The objective of this study therefore was to investigate the likely mode of inheritance of RLS. RLS patients and their first-degree relatives were investigated and classified in RLS affected and RLS nonaffected subjects. Assessments were based on direct, personal standardized diagnostic interviews. Complex segregation analysis was performed with the families stratified according to the mean age at onset of the disease within the families. Two hundred thirty-eight RLS patients, 537 first-degree relatives, and 133 spouses were interviewed. Two groups of families were stratified: mean age at onset up to 30 years of age (Group A) and older than 30 years (Group B; p < 0.005). In Group A, segregation analysis strongly favored a single major gene acting autosomal dominant with a multifactorial component. Parameter estimates were 0.003 for the allele frequency, 1.0 for the penetrance, and 0.005 for the phenocopy rate. In Group B, no evidence for a major gene could be elucidated. The segregation pattern found in our families argues for an autosomal allele acting dominantly in RLS families with an early age at onset of symptoms and suggests that RLS is a causative heterogeneous disease.