Pupil Size Tracks Attentional Performance In Attention-Deficit/Hyperactivity Disorder.

Attention-deficit/hyperactivity disorder (ADHD) diagnosis is based on reported symptoms, which carries the potential risk of over- or under-diagnosis. A biological marker that helps to objectively define the disorder, providing information about its pathophysiology, is needed. A promising marker of cognitive states in humans is pupil size, which reflects the activity of an 'arousal' network, related to the norepinephrine system. We monitored pupil size from ADHD and control subjects, during a visuo-spatial working memory task. A sub group of ADHD children performed the task twice, with and without methylphenidate, a norepinephrine-dopamine reuptake inhibitor. Off-medication patients showed a decreased pupil diameter during the task. This difference was no longer present when patients were on-medication. Pupil size correlated with the subjects' performance and reaction time variability, two vastly studied indicators of attention. Furthermore, this effect was modulated by medication. Through pupil size, we provide evidence of an involvement of the noradrenergic system during an attentional task. Our results suggest that pupil size could serve as a biomarker in ADHD.

[Monitoring indicators of the program "Chile Grows with You" 2008-2011]. / Monitoreo de los indicadores del Programa "Chile Crece Contigo" 2008-2011.

OBJECTIVE: To monitor coverage and outcomes associated with the activities of the integrated protection system for early childhood Chile Grows with You (CHCC), which includes the comprehensive psychosocial development of children between 18 months and 3 years old, in each of the 29 Health Services of the country, as well as the changes observed after 4 years. MATERIAL AND METHOD: Database analysis of all local public networks in the country between 2008 and 2011 was performed. The application of the test regarding psychomotor development, prevalence of development delay and risk, participation of mothers in educational workshops, home visits and recovery rate of deficient children by age were studied. Median and observed changes of each indicator were analyzed developing a ranking based on the results observed. RESULTS: Approximately 75% of children were evaluated, with a prevalence of delay or risk of about 5% and a rate of recovery close to 50%. The participation of mothers in educational workshops increased from 7.6 to 11.0% (p<0.001) and home visits to developmentally delayed children increased 6 times between 2009 and 2011 (p<0.001). Most changes were positive, although the prevalence of developmentally delayed children under 2 years slightly increased (0.6%), and the recovery of 3 year olds decreased (-14.4%). A great variability was observed among the Health Services. CONCLUSIONS: There are some positive results in relation to psychomotor development, with significant regional differences. A lower than expected deficit rate regarding psychomotor development was observed, which implies the need to further analyze the instrument used or the conditions of application.

Attention-deficit hyperactivity disorder involves differential cortical processing in a visual spatial attention paradigm.

OBJECTIVE: Inattention is undoubtedly one of the main characteristics of Attention-deficit hyperactivity disorder (ADHD). Nevertheless, a growing corpus of evidence shows that not all attentional processes are affected in this condition. This study aimed to explore the distribution of attentional resources in children with ADHD via a spatially shifted double-oddball visual task. METHODS: We recorded event-related potentials (ERPs) for all visual stimuli. Subjects were instructed to allocate attention in a specific area of visual space while ignoring all stimuli presented outside. Ten male children (age: 9-14; mean = 11.6 +/- 2.1) who met DSM-IV criteria for the ADHD combined subtype participated in the study, along with ten age- and sex-matched healthy controls (9-14; mean = 11.2 +/- 2.3). RESULTS: ADHD subjects showed late differential cortical responses to initially suppressed irrelevant stimuli. The amplitude of early N1-P1 components were mainly modulated by stimulus location and showed no significant differences between groups, but a late P300-like positivity was clearly evoked in the ADHD group by peripheral stimuli. CONCLUSIONS: These results suggest that ADHD may not compromise the early attentional spatial filter but rather entails a different distribution of attentional resources at later stages of cortical processing. Perhaps these differences may be attributable to individual differences in attentional mechanisms. SIGNIFICANCE: ADHD may not affect initial focusing of visual attention but rather the allocation of processing resources in later stages.

Presencia de los alelos DRD4/7R y DAT1/10R en miembros de familias chilenas con síndrome de déficit atencional con hiperactividad / Presence of DRD4/7R and DAT1/10R allele in Chilean family members with attention deficit hyperactivity disorder

BACKGROUND: Genes for dopamine receptor DRD4 and dopamine transporter DAT1 have been implicated in attention deficit with hyperactivity disorder (ADHD). However, the findings are not conclusive. More studies in populations with different genetic backgrounds may contribute to solve the discrepancies observed. AIM: To test the hypothesis that affected members of Chilean families exhibit higher frequencies of the DRD4/7R and DAT1/10R alleles then their healthy sibs. MATERIAL AND METHODS: The parents of 51 children belonging to families of the Metropolitan Region of Chile, were approached to obtain clinical histories and blood samples, after the signature of a written informed consent. ADHD was diagnosed according to DSM-IV criteria, ancd intellectual coefficient was tested using the WISC-R test. Genomic DNA was extracted from lymphocytes and amplified by PCR. RESULTS: The 7R allele was identified in 13 out of 26 subjects diagnosed as ADHD and in 6 of 25 healthy sibs (p < 0.05). Parents with a history of ADHD, were conmpared with their healthy counterparts, exhibiting an identical tendency, that did not reach statistical significance. No significant differences in the frequencies of DAT1/10R alleles, were observed between cases and controls or their parents. CONCLUSIONS: Our results showed that ADHD in Chilean families is associated with the presence of DRD4/7R allele.

The alien hand syndrome: classification of forms reported and discussion of a new condition.

The term "alien hand" refers to a variety of clinical conditions whose common characteristic is the uncontrolled behavior or the feeling of strangeness of one extremity, most commonly the left hand. A common classification distinguishes between the posterior or sensory form of the alien hand, and the anterior or motor form of this condition. However, there are inconsistencies, such as the phenomenon of diagonistic dyspraxia, which is largely a motor syndrome despite being more frequently associated with posterior callosal lesions. We discuss critically the existing nomenclature and we also describe a case recently reported by us which does not fit any previously reported condition, termed agonistic dyspraxia. We propose that the cases of alien hand described in the literature can be classified into at least five broad categories: (i) diagonistic dyspraxia and related syndromes, (ii) alien hand, (iii) way-ward hand and related syndromes, (iv) supernumerary hands and (v) agonistic dyspraxia.