Subclinical executive function impairment in children with asymptomatic, treated phenylketonuria: A comparison with children with immunodeficiency virus

In this study we compared the neuropsychological profile of phenylketonuria (PKU) and human immunodeficiency virus (HIV) to examine the specificity of the executive function (EF) impairment reported in these two patologies. A total of 55 age-matched children and adolescents were assessed, including 11 patients with PKU, 16 patients with HIV and 28 healthy controls, underwent a neuropsychological assessment. Although neither the PKU nor the HIV group scored below the normative ranges, both groups showed lower scores in neuropsychological tests engaging EFs than controls. In addition, compared to patients with PKU the HIV group performed significantly worse in the Trail-Making Test A, Corsi S…

The Neuropsychological Profile of Infantile Duchenne Muscular Dystrophy

It has been shown that children with Duchenne muscular dystrophy (DMD) exhibit specific cognitive deficits. However, the neuropsychological profile has not yet been fully characterized. In order to control for the contribution of motor impairments as a confounding variable that is usually present when assessing children with muscular pathologies, we compared children with DMD to a group of children with an autoimmune pathology that does not entail either brain or cognitive dysfunction but does imply motor impairment: juvenile rheumatoid arthritis (JRA). An extensive neuropsychological evaluation was administered, including intelligence, perception, language, memory and learning, attention, …

Assessing inter- and intra-individual cognitive variability in patients at risk for cognitive impairment: the case of minimal hepatic encephalopathy

Recent evidence reveals that inter- and intra-individual variability significantly affects cognitive performance in a number of neuropsychological pathologies. We applied a flexible family of statistical models to elucidate the contribution of inter- and intra-individual variables on cognitive functioning in healthy volunteers and patients at risk for hepatic encephalopathy (HE). Sixty-five volunteers (32 patients with cirrhosis and 33 healthy volunteers) were assessed by means of the Inhibitory Control Task (ICT). A Generalized Additive Model for Location, Scale and Shape (GAMLSS) was fitted for jointly modeling the mean and the intra-variability of Reaction Times (RTs) as a function of so…

Sociocognitive factors associated with nonadherence to medication after hospital discharge

Poor adherence to prescribed medication is a well-known problem and continues to be a major challenge in all medical specialties. Unlike previous studies that have mainly focused on nonadherence behaviors in specific diseases, this study sought to examine socio-cognitive factors associated with nonadherence behavior in a sample of a general clinical population. A questionnaire investigating socio-demographic and cognitive factors and a telephone follow-up interview were administered to 84 patients recruited in a General Medicine Unit before their discharge. Half of the participants were informed about that follow-up procedure. One month after hospital discharge, 42% of uninformed patients r…

Neuropsychological performance 10 years after immunization in infancy with thimerosal-containing vaccines

OBJECTIVE. Thimerosal, a mercury compound used as a preservative in vaccines administered during infancy, has been suspected to affect neuropsychological development. We compared the neuropsychological performance, 10 years after vaccination, of 2 groups of children exposed randomly to different amounts of thimerosal through immunization. METHODS. Children who were enrolled in an efficacy trial of pertussis vaccines in 1992–1993 were contacted in 2003. Two groups of children were identified, according to thimerosal content in vaccines assigned randomly in the first year of life (cumulative ethylmercury intake of 62.5 or 137.5 μg), and were compared with respect to neuropsychological outcome…

Age-related differences in the neural correlates of remembering time-based intentions.

The present study used event-related potentials (ERPs) to explore the effect of age on the neural correlates of monitoring processes involved in time-based prospective memory.In both younger and older adults, the addition of a time-based prospective memory task to an ongoing task led to a sustained ERP activity broadly distributed over the scalp. Older adults, however, did not exhibit the slow wave activity observed in younger adults over prefrontal regions, which is considered to be associated with retrieval mode. This finding indicates that age-related decline in intention maintenance might be one source of the impaired prospective memory performance displayed by older adults. An 'anterio…

The impact of a concurrent motor task on auditory and visual temporal discrimination tasks

Previous studies have shown the presence of an interference effect on temporal perception when participants are required to simultaneously execute a nontemporal task. Such interference likely has an attentional source. In the present work, a temporal discrimination task was performed alone or together with a self-paced finger-tapping task used as concurrent, nontemporal task. Temporal durations were presented in either the visual or the auditory modality, and two standard durations (500 and 1, 500 ms) were used. For each experimental condition, the participant’s threshold was estimated and analyzed. The mean Weber fraction was higher in the visual than in the auditory modality, but only for…

Aging and prospective memory: the role of working memory and monitoring processes

Background and aims: Remembering to execute an earlier planned action is essential in everyday life, and is a prerequisite for independent living in old age. The purpose of the present study was to determine the influence of age in performing a prospective memory (PM) task and to analyze the differential contribution of working memory and attentional monitoring demands. Methods: In Experiment 1, a group of young and two groups of old adults were assigned to one of two low-demanding conditions: a picture-naming task (only-Naming) and a picture-naming plus a PM task (Naming+PM). In Experiment 2, a group of young and two groups of old adults performed one of two high-demanding conditions, in w…

The time course of temporal discrimination: An ERP study

Objective: The question of how temporal information is processed by the brain is still a matter of debate. This study aimed to elucidate the brain electrical activity associated with a visual temporal discrimination task. Methods: For this purpose, 44 participants were required to compare pairs of sequentially presented time intervals: a fixed standard interval (1000 ms), and an equal-to-standard, longer (1200 ms) or shorter (800 ms) comparison interval. Behavioural data and event-related potentials (ERPs) were analyzed. Results: Long intervals were more rapidly identified than short intervals. The amplitude of the contingent negative variation (CNV) found at frontocentral sites before the …

Transcranial Magnetic Stimulation and Neuroimaging Coregistration

The development of neuroimaging techniques is one of the most impressive advancements in neuroscience. The main reason for the widespread use of these instruments lies in their capacity to provide an accurate description of neural activity during a cognitive process or during rest. This important advancement is related to the possibility to selectively detect changes of neuronal activity in space and time by means of different biological markers. Specifically, functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and nearinfrared spectroscopy (NIRS) use metabolic markers of ongoing neuronal activity to provide a…

Automatic Temporal Expectancy: A High-Density Event-Related Potential Study

How we compute time is not fully understood. Questions include whether an automatic brain mechanism is engaged in temporally regular environmental structure in order to anticipate events, and whether this can be dissociated from task-related processes, including response preparation, selection and execution. To investigate these issues, a passive temporal oddball task requiring neither time-based motor response nor explicit decision was specifically designed and delivered to participants during high-density, event-related potentials recording. Participants were presented with pairs of audiovisual stimuli (S1 and S2) interspersed with an Inter-Stimulus Interval (ISI) that was manipulated acc…

Time-on-Task in Children with ADHD: An ex-Gaussian Analysis

AbstractAlthough it is widely known that high intra-individual variability (IIV) is a key characteristic of attention deficit/hyperactivity disorder (ADHD), a detailed exploration of the IIV pattern during the time course of a cognitive task has never been carried out. In this study, 30 children with ADHD and 30 controls, were administered the Conners’ Continuous Performance Task (CPT-II). The across-block individual performance of the groups was analyzed using an ex-Gaussian approach, which enabled a clearer understanding of how individual response times (RTs) fluctuate during a task in comparison with conventional measures of central tendency. While the conventional measures showed a sign…

Electrophysiological correlates of strategic monitoring in event-based and time-based prospective memory

Prospective memory (PM) is the ability to remember to accomplish an action when a particular event occurs (i.e., event-based PM), or at a specific time (i.e., time-based PM) while performing an ongoing activity. Strategic Monitoring is one of the basic cognitive functions supporting PM tasks, and involves two mechanisms: a retrieval mode, which consists of maintaining active the intention in memory; and target checking, engaged for verifying the presence of the PM cue in the environment. The present study is aimed at providing the first evidence of event-related potentials (ERPs) associated with time-based PM, and at examining differences and commonalities in the ERPs related to Strategic M…

Spatiotemporal Neurodynamics Underlying Internally and Externally Driven Temporal Prediction: A High Spatial Resolution ERP Study

Abstract Temporal prediction (TP) is a flexible and dynamic cognitive ability. Depending on the internal or external nature of information exploited to generate TP, distinct cognitive and brain mechanisms are engaged with the same final goal of reducing uncertainty about the future. In this study, we investigated the specific brain mechanisms involved in internally and externally driven TP. To this end, we employed an experimental paradigm purposely designed to elicit and compare externally and internally driven TP and a combined approach based on the application of a distributed source reconstruction modeling on a high spatial resolution electrophysiological data array. Specific spatiotemp…

Effect of duration of breastfeeding on neuropsychological development at 10 to 12years of age in a cohort of healthy children

Aim The aim of this article was to explore the effect of duration of breastfeeding on neurocognitive development. Method The long-term effect of breastfeeding on neurodevelopment was examined through a battery of neuropsychological tests in 1403 children (693 females, 710 males; mean age 11y 9mo [SD 6mo], range: 10y 3mo-12y 8mo) who were originally recruited at 6 to 12weeks of age for a clinical trial on acellular pertussis vaccines. An estimated IQ was obtained from scores of the vocabulary, similarities, block design, and coding tests. Breastfeeding data had been prospectively collected throughout the first year of life. Duration of exclusive breastfeeding was defined as the time during w…

Electrophysiological evidence for a differential activation of the brain network associated with temporal discrimination processing