Montreal Cognitive Assessment (MoCA) for HIV-Associated Neurocognitive Disorders

Neuropsychology Review - This study aims to systematically review the evidence on the accuracy of the Montreal Cognitive Assessment (MoCA) test for diagnosing HIV–associated neurocognitive...     

Language experience influences audiovisual speech integration in unimodal and bimodal bilingual infants

Infants as young as 2 months can integrate audio and visual aspects of speech articulation. A shift of attention from the eyes towards the mouth of talking faces occurs around 6 months of age in monolingual infants. However, it is unknown whether this pattern of attention during audiovisual speech processing is influenced by speech and language experience in infancy. The present study investigated this question by analysing audiovisual speech processing in three groups of 4‐ to 8‐month‐old infants who differed in their language experience: monolinguals, unimodal bilinguals (infants exposed to two or more spoken languages) and bimodal bilinguals (hearing infants with Deaf mothers). Eye‐tracking was used to study patterns of face scanning while infants were viewing faces articulating syllables with congruent, incongruent and silent auditory tracks. Monolinguals and unimodal bilinguals increased their attention to the mouth of talking faces between 4 and 8 months, while bimodal bilinguals did not show any age difference in their scanning patterns. Moreover, older (6.6 to 8 months), but not younger, monolinguals (4 to 6.5 months) showed increased visual attention to the mouth of faces articulating audiovisually incongruent rather than congruent faces, indicating surprise or novelty. In contrast, no audiovisual congruency effect was found in unimodal or bimodal bilinguals. Results suggest that speech and language experience influences audiovisual integration in infancy. Specifically, reduced or more variable experience of audiovisual speech from the primary caregiver may lead to less sensitivity to the integration of audio and visual cues of speech articulation.     

Association between polymorphisms in the dopamine transporter gene and depression: evidence for a gene-environment interaction in a sample of juvenile detainees

Previous research has generated examples of how genetic and environmental factors can interact to create risk for psychopathology. Using a gene-by-environment (G x E) interaction design, we tested whether three polymorphisms in the dopamine transporter gene (DAT1, also referred to as SLC6A3, located at 5p15.33) interacted with maternal parenting style to predict first-onset episodes of depression. Participants were male adolescents (N= 176) recruited from a juvenile detention center in northern Russia. As hypothesized, one of the polymorphisms (rs40184) moderated the effect of perceived maternal rejection on the onset of major depressive disorder, as well as on suicidal ideation. Further, this G x E interaction was specific to depression; it did not predict clinically significant anxiety. These results highlight the need for further research investigating the moderating effects of dopaminergic genes on depression.     

The epidemiology of suicide-related outcomes in Mexico

Nationally representative data from the Mexican National Comorbidity Survey are presented on the lifetime prevalence and age-of-onset (AOO) distributions of suicide ideation, plan and attempt and on temporally prior demographic and DSM-IV psychiatric risk factors. Lifetime ideation was reported by 8.1% of respondents, while 3.2% reported a lifetime plan and 2.7% a lifetime suicide attempt. Onset of all outcomes was highest in adolescence and early adulthood. The risk of transition from suicide ideation to plan and attempt was highest within the first year of onset of ideation. The presence of one or more temporally prior DSM-IV/CIDI (Composite International Diagnostic Instrument) disorder was strongly related to each suicide-related outcome. Suicidal outcomes are prevalent, have an early AOO, and are strongly related to temporally prior mental disorders in Mexico. Given the early AOO, intervention efforts need to focus more than currently on children and adolescents with mental disorders to be effective in prevention.     

Paternal absence and international migration: stressors and compensators associated with the mental health of Mexican teenagers of rural origin

Mexico-U.S. migration creates situations that may cause psychological distress. The purpose of this research project was to study the impact of father's physical absence due to international migration (FPAIM) on adolescent offspring of rural immigrants from Zacatecas, Mexico. Stressors and compensators were studied from the adolescent's perspective and were analyzed using a stress-mediator-consequences theoretical framework. Qualitative (n = 24) and quantitative (n = 310) methodologies were used with a nonrandom sample of adolescents. Results show that the FPAIM is an ambivalent experience for adolescents that has positive and negative elements. Though migrants' children seem to be more vulnerable to psychosocial stress than are the offspring of nonmigrants, gender, not father's absence, appears to be the most important risk factor for psychological distress.     

Macaque monkeys discriminate pitch relationships

This study demonstrates that non-human primates can categorize the direction of the pitch change of tones in a sequence. Two Macaca fascicularis were trained in a positive-reinforcement behavioral paradigm in which they listened to sequences of a variable number of different acoustic items. The training of discriminating pitch direction was divided into three phases with increasing task complexity. In the first two phases, subjects learned to employ a same/different rule. In phase 1, they discriminated acoustic items of different sound quality. Subjects had to respond when there was a change from repeating noise bursts to repeating click trains or vice versa. In phase II, acoustic items differed along one physical dimension only. Subjects had to respond to a change of the frequency of a repeating series of pure tones. In phase III, sequences consisted of three series of repeating tones of different frequency. Subjects were required to respond when the frequency of the tones changed in a downward direction and to refrain from responding when the frequency remained constant or increased. After several ten thousand trials, subjects categorized pitch direction well above chance level. The discrimination was performed over a 4.5-octave range of frequencies and was largely independent of the temporal and ordinal position of the downward pitch direction within the sequence. These results demonstrate that monkeys can recognize pitch relationships and thus that monkeys have the concept of ordinal relations between acoustic items.     

Gender and lexical access in Bulgarian

Two procedures were used to explore the effects of semantic and grammatical gender on the recognition and processing of Bulgarian nouns, in relation to other factors that are known to affect lexical access. This study in a three-gender language was modeled on previous work in Italian, a two-gender language (Bates, Devescovi, Pizzamiglio, D'Amico, & Hernandez, 1995). Words were presented auditorily in randomized lists in two tasks: (1) repeat the word as quickly as possible and (2) determine the grammatical gender of the noun as soon as possible and indicate the decision by pressing a button. Reaction times in both tasks were influenced by phonological factors, word frequency, and irregularity of gender marking, but semantic and grammatical gender affected only gender monitoring. The significant contribution of semantic gender to processing in Bulgarian contrasts with previous findings for Italian. Also, we obtained an interaction between sex of the subject and noun gender, reflecting a bias toward one's own grammatical gender "counterpart" (especially for females). Reanalysis of the prior study in Italian showed a similar interaction but confirmed no effects of the semantic gender of the noun, suggesting that these two natural gender effects can dissociate. Possible reasons for cross-linguistic differences are discussed, with implications for comparative studies of gender and lexical access.     

Prosodic processing by children: an fMRI study

Prosodic information in the speech signal carries information about linguistic structure as well as emotional content. Although children are known to use prosodic information from infancy onward to assist linguistic decoding, the brain correlates of this skill in childhood have not yet been the subject of study. Brain activation associated with processing of linguistic prosody was examined in a study of 284 normally developing children between the ages of 5 and 18 years. Children listened to low-pass filtered sentences and were asked to detect those that matched a target sentence. fMRI scanning revealed multiple regions of activation that predicted behavioral performance, independent of age-related changes in activation. Likewise, age-related changes in task activation were found that were independent of differences in task accuracy. The overall pattern of activation is interpreted in light of task demands and factors that may underlie age-related changes in task performance.     

Babies' logic activity: a differential study

From a neuroconstructivist point of view based on infant cognitive development, the aim of this study is to get to know and compare the logical organization and content of the spontaneous activity of babies with alternative developmental courses (typical babies and Down's Syndrome ones). A fundamental form of logic is observed since the beginning of babies' interaction with their environment. This protologic is constructed through their organised and significative activity with the environment and it results in the elaboration of logico-mathematical and physical knowledge. Using Systematic Observation, we recorded the spontaneous activity of n=20 babies, (n=10 typical babies, n=10 Down Syndrome babies), with a cognitive developmental level of 1; 3 years (15 months). Microgenetical and statistical analyses were applied and the results obtained showed a reduced logical content and organization of the activity of Down's Syndrome babies, which corroborates and amplifies the results of previous research works. These results make evident the need to plan early educational intervention in order to optimize babies' developmental resources.