Motor dysfunction in mild cognitive impairment as tested by kinematic analysis and transcranial magnetic stimulation

ObjectivePrevious studies have demonstrated voluntary movement alterations as well as motor cortex excitability and plasticity changes in patients with mild cognitive impairment (MCI). To investigate the pathophysiology of movement abnormalities in MCI, we tested possible relationships between movement abnormalities and primary motor cortex alterations in patients.MethodsFourteen amnestic MCI (aMCI) patients and 16 healthy controls were studied. Cognitive assessment was performed using clinical scales. Finger tapping was recorded by a motion analysis system. Transcranial magnetic stimulation was used to test the input/output curve of motor evoked potentials, intracortical inhibition, and short-latency afferent inhibition. Primary motor cortex plasticity was probed by theta burst stimulation. We investigated correlations between movement abnormalities, clinical scores, and cortical neurophysiological parameters.ResultsMCI patients showed less rhythmic movement but no other movement abnormalities. Cortical excitability measures were normal in patients, whereas plasticity was reduced. Movement rhythm abnormalities correlated with frontal dysfunction scores.ConclusionOur study in MCI patients demonstrated abnormal voluntary movement and plasticity changes, with no correlation between the two. Altered rhythm correlated with frontal dysfunction.SignificanceOur results contribute to the understanding of pathophysiological mechanisms of motor impairment in MCI.     

Stimulus probability affects the visual N700 component of the event-related potential

ObjectiveTo examine whether the occipito-temporal visual N700 component of the event-related potential is sensitive to stimulus probabilities.MethodsP1, N1, P3, and, in particular, the occipito-temporal N700 component of the event-related potential were analysed in response to frequent and rare non-target letters of a continuous performance task in 200 healthy adolescents. Additionally, amplitude habituation with time was examined for the occipito-temporal N700 and N1 components.ResultsThe visual P1, N1, and occipito-temporal N700 components were significantly larger in response to rare letters than to frequent letters, whereas the P3 component demonstrated no amplitude difference. Over time, the occipito-temporal N700 amplitude decreased in response to the rare letters, while the N1 amplitude increased, to both, frequent and rare letters.ConclusionsThis study provides first evidence that the visual occipito-temporal N700 is sensitive to stimulus probabilities, suggesting an enhanced post-processing of rare stimuli in secondary visual areas. The distinct habituation patterns of occipito-temporal N700 and N1 amplitudes distinguish repetition effects on stimulus post-processing (N700) from those on perception (N1).SignificanceThe enhanced N700 component to rare stimuli might reflect an orienting response and underlying attentional processes. The N700 sensitivity to stimulus probabilities should be examined in patient groups with attentional deficits.     

Sexual Function,Sexual Dysfunctions,and ADHD: A Systematic Literature Review

BackgroundThe scientific literature on sexuality among mentally ill patients clearly shows a higher prevalence of sexual disorders for many mental disorders, but little is known about sexuality in individuals suffering from ADHD. Clinicians will often assume that specific difficulties of ADHD are bound to affect sexual functioning.AimThe aim of this study was to provide a review of the literature to gain better knowledge about sexuality in subjects with ADHD and to discuss screening and management of their potential sexual problems.MethodsA systematic review of the literature was performed in Pubmed, PsychInfo, and Embase databases.Main Outcome MeasuresThe main outcome measures were sexual function and sexual dysfunctions.ResultsThe studies indicated that subjects with ADHD report more sexual desire, more masturbation frequency, less sexual satisfaction, and more sexual dysfunctions than the general population.Clinical ImplicationsClinicians working with subjects with ADHD should explore the quality of their sexual life.Strengths & LimitationsThis is the first systematic review of the sexuality of individuals with ADHD. However, the results are limited by the small number of studies, by the small sample size of many studies, and the potential for bias.ConclusionsADHD is a mental disorder affecting sexual health. Further studies are warranted to learn more about sexuality in subjects with ADHD.Soldati L, Bianchi-Demicheli F, Schockaert P, et al. Sexual Function, Sexual Dysfunctions, and ADHD: A Systematic Literature Review. J Sex Med 2020;17:1653–1664.