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Neurophysiological studies exploring involuntary attention have reported that electroencephalographic (EEG) measures can indicate impaired neural processing from initial stages of Parkinson's disease (PD). Since involuntary attention is regulated by right hemisphere networks and PD generally initiates its motor symptomatology unilaterally, whether involuntary attention is impaired depending on the onset side of PD remains unknown.We compared the neurophysiological correlates of involuntary attention among a PD group with left-side onset (L-PD), a PD group with right-side onset (R-PD) symptomatology, and a healthy control group (HC). All participants performed an auditory involuntary attention task while a digital EEG was recorded.Our main finding was a reduction both in the P3a amplitude and evoked delta-theta phase alignment in the L-PD group compared to the HC. Further, there was a significant correlation between P3a amplitude and disease duration in the R-PD, but not in the L-PD group. Behaviorally, both clinical groups, and in particular L-PD, showed reduced orientation towards novel stimuli, and no reduction of distraction effects during the experiment.Our results indicate that involuntary attention is differentially impaired in patients with left side onset of symptoms. Involuntary attention impairment might be present from initial stages of left onset PD and become progressively compromised in patients with right onset PD.The onset side of symptomatology should be considered for attentional impairment in PD.

This study validates a new Spanish-language version of the Coordinate Response Measure (CRM) corpus using a well-established measure of spatial release from masking (SRM). Participants were 96 Spanish-speaking young adults without hearing complaints in Mexico City. To present the Spanish-language SRM test, we created new recordings of the CRM with Spanish-language Translations and updated the freely available app (PART; https://ucrbraingamecenter.github.io/PART_Utilities/ ) to present materials in Spanish. In addition to SRM, we collected baseline data on a battery of non-speech auditory assessments, including detection of frequency modulations, temporal gaps, and modulated broadband noise in the temporal, spectral, and spectrotemporal domains. Data demonstrate that the newly developed speech and non-speech tasks show similar reliability to an earlier report in English-speaking populations. This study demonstrates an approach by which auditory assessment for clinical and basic research can be extended to Spanish-speaking populations for whom testing platforms are not currently available.

Introduction: Although working memory (WM) dysfunction has been proposed as a schizophrenia (SZ) endophenotype, the specific impaired component (encoding or maintenance) in patients and unaffected relatives remains inconclusive. We compared auditory-verbal and visuospatial WM in patients with SZ, unaffected siblings (USs), and healthy controls under 2 response conditions: immediate (encoding condition) and delayed (maintenance condition). Methods: We included 22 participants per group, similar in age and gender. Three WM tests (Spatial Span, Backward Digit Span, and Letter-Number Span) were administered under both conditions in a counterbalanced manner to all participants. Results: Poorer performance was found in the SZ group for all tests (p < 0.001). USs showed a better performance than patients, but worse than controls (p < 0.05), except for the Backward Digit Span test, in which their performance was similar to that of the SZ group. The effect of the delayed response in all tasks was not significant in any group. Conclusion: Our results indicate that WM impairment, including auditory-verbal and visuospatial modalities, corresponds to a stable feature of the disease as it is present in USs, thus confirming its potential endophenotypic property in SZ patients. No effect of the delayed response was observed, suggesting failures in encoding in both patients and USs.

Objective. To explore whether maternal sensitivity is associated with Autism Spectrum Disorder (ASD) severity in children with and without ASD. Design. The samples consisted of 25 Mexican dyads of children with ASD (aged 3.1-6.9 years) and their mothers (aged 20-47 years) and 24 Mexican dyads of children without ASD (aged 3.4-6.7 years) and their mothers (aged 24-45 years). Maternal sensitivity and ASD severity symptoms were scored from 2-h videos of mother-child daily interactions. Results. A between-group comparison showed a trend toward less severe ASD in children with highly sensitive mothers, specifically in the Nonverbal Communication subdomain. Conclusions. Greater maternal sensitivity is associated with improved social ability in children with ASD.

Accessibility issues, especially in developing countries, have prevented the evaluation of diverse hearing abilities beyond the pure tone audiogram in the general population. PART is a free-access automated auditory measurement tool that can address accessibility issues by providing a wide variety of auditory psychophysical measures in multiple languages on standard relatively low-cost commercial interfaces such as tablets and smart phones. Here, we show that PART can complement traditional audiological tests to better account for people’s hearing complaints. Forty-four adults between 40 and 80 years old were tested in Mexico City with a traditional clinical battery (otoacoustic emissions and pure tone audiogram) and a battery of PART-based central auditory processing and speech-on-speech competition measures. Several measures from the PART battery correlated with self-reported hearing difficulties, and the spatial release from masking task was best able to capture this variance. These preliminary data support the inclusion of a speech-on-speech masking as a complement to traditional clinical measures to better account for the hearing complaints of the public. Furthermore, we show PART-based version of this test can be implemented in a clinical setting in Mexico and produce comparable results to those obtained in developed countries like the United States of America.

BackgroundCognition heavily relies on social determinants and genetic background. Latin America comprises approximately 8% of the global population and faces unique challenges, many derived from specific demographic and socioeconomic variables, such as violence and inequality. While such factors have been described to influence mental health outcomes, no large-scale studies with Latin American population have been carried out. Therefore, we aim to describe the cognitive performance of a representative sample of Latin American individuals with schizophrenia and its relationship to clinical factors. Additionally, we aim to investigate how socioeconomic status (SES) relates to cognitive performance in patients and controls.MethodsWe included 1175 participants from five Latin American countries (Argentina, Brazil, Chile, Colombia, and Mexico): 864 individuals with schizophrenia and 311 unaffected subjects. All participants were part of projects that included cognitive evaluation with MATRICS Consensus Cognitive Battery and clinical assessments.ResultsPatients showed worse cognitive performance than controls across all domains. Age and diagnosis were independent predictors, indicating similar trajectories of cognitive aging for both patients and controls. The SES factors of education, parental education, and income were more related to cognition in patients than in controls. Cognition was also influenced by symptomatology.ConclusionsPatients did not show evidence of accelerated cognitive aging; however, they were most impacted by a lower SES suggestive of deprived environment than controls. These findings highlight the vulnerability of cognitive capacity in individuals with psychosis in face of demographic and socioeconomic factors in low- and middle-income countries.

We explored the neurophysiological activity underlying auditory novelty detection in antipsychotic-naive patients with a first episode of psychosis (FEP). Fifteen patients with a non-affective FEP and 13 healthy controls underwent an active involuntary attention task along with an EEG acquisition. Time-frequency representations of power, phase locking, and fronto-parietal connectivity were calculated. The P3a event-related potential was extracted as well. Compared to controls, the FEP group showed reduced theta phase-locking and fronto-parietal connectivity evoked by deviant stimuli. Also, the P3a amplitude was significantly reduced. Moreover, reduced theta connectivity was associated with more severe negative symptoms within the FEP group. Reduced activity (phase-locking and connectivity) of novelty-related theta oscillations, along with P3a reduction, may represent a failure to synchronize large-scale neural populations closely related to fronto-parietal attentional networks, and might be explored as a potential biomarker of disease severity in patients with emerging psychosis, given its association with negative symptoms.

Portable automated rapid testing of central auditory processing measures implemented in the app PART (https://braingamecenter.ucr.edu/games/p-a-r-t/) were adapted for Spanish-speaking populations. This adaptation included the generation of a corpus equivalent to the CRM to test a speech-on-speech masking task, in addition to frequency modulation tasks, temporal gap, temporal, spectral and spectro-temporal modulations, and pure tone detection in noise. This battery of tests was selected for its potential clinical utility and its previous validation across several settings including remote testing with participant-owned headphones, tablets or smartphones. Here, we tested 96 young adults in Mexico City (ages 18–45) with normal hearing. As expected, distributions of scores were similar to previously reported norms for the English-language version of the battery in English-speaking populations. Scores for the newly developed Spanish-language speech-on-speech masking tests were also similar to data previously reported in English-speaking populations. Furthermore, there was no significant effects of age or subjective hearing handicap (HHIA) in any of the tests. This study can be now used as a normative dataset, and the adapted battery can be used as an accsessible tool (available freely online) for valid and reliable testing of central auditory processing measures in Spanish-language populations.

Objective Cognitive decline does not always follow a predictable course in Parkinson’s disease (PD), with some patients remaining stable while others meet criteria for dementia from early stages. Functional connectivity has been proposed as a good correlate of cognitive decline in PD, although it has not been explored whether the association between this connectivity and cognitive ability is influenced by disease duration, which was our objective. Methods We included 30 patients with PD and 15 healthy controls (HC). Six cognitive domains were estimated based on neuropsychological assessment. Phase-based connectivity at frontal and posterior cortical regions was estimated from a resting EEG. Results The PD group showed significant impairment for the executive, visuospatial, and language domains compared with HC. Increased connectivity at frontal regions was also found in the PD group. Frontal delta and theta connectivity negatively influenced general cognition and visuospatial performance, but this association was moderated by disease duration, with increased connectivity predicting worse performance after 8 years of disease duration. Conclusion Subtle neurophysiological changes underlie cognitive decline along PD progression, especially around a decade after motor symptoms onset. Significance Connectivity of EEG slow waves at frontal regions might be used as a predictor of cognitive decline in PD.

Objective: To assess the frequency of somatization and its association with motor, nonmotor symptoms, and quality of life in persons with Parkinson disease (PD). Methods: A cross-sectional case–control study was carried out. Assessments included the List of 90 Symptoms somatic factor (SCL-90-R SOM), Movement Disorder Society Unified Parkinson’s Ratings Scale (MDS-UPDRS), Non-Motor Symptom Scale (NMSS), Montreal Cognitive Assessment (MoCA), and Parkinson Questionnaire-8 (PDQ-8). Results: A total 93 persons with PD and 93 controls were included. Somatization within the PD group was 2 times more frequent compared to the control group (43% vs 21.5%, P = .003). Persons with PD had higher NMSS total scores (48.6 ± 42.6 vs 28.3 ± 30.4, P = .001). Patients with PD with somatization had worst MDS-UPDRS, NMSS, MoCA, and PDQ-8 (all P < .05). Conclusion: Somatization is more frequent in persons with PD compared to healthy controls. Somatization in PD is associated with nonmotor symptoms and worst quality of life.

Background Abnormally elevated levels of gamma-aminobutyric acid (GABA) in the medial prefrontal cortex (mPFC) have been reported in antipsychotic-free patients with schizophrenia. Whether such GABA elevations are also present in other brain regions and persist after antipsychotic treatment has not been previously investigated. Methods Twenty-eight antipsychotic-naive patients with first-episode psychosis (FEP) and 18 healthy control subjects completed the study. Following baseline proton magnetic resonance spectroscopy scans targeting the mPFC and a second region, the dorsal caudate, patients with FEP were treated with oral risperidone for 4 weeks at an initial dose of 1 mg/day that was titrated as necessary based on clinical judgment. After the 4-week treatment period, both groups were brought back to undergo outcome magnetic resonance spectroscopy scans, which were identical to the scans conducted at baseline. Results At baseline, higher GABA levels were found both in the mPFC and in the dorsal caudate of patients with FEP compared with healthy control subjects. Following 4 weeks of antipsychotic treatment, GABA levels in patients with FEP decreased relative to baseline in the mPFC, but decreased only at the trend level relative to baseline in the dorsal caudate. For either brain region, GABA levels at 4 weeks or posttreatment did not differ between patients with FEP and healthy control subjects. Conclusions The results of the present study documented elevations of GABA levels both in the mPFC and, for the first time, in the dorsal caudate of antipsychotic-naive patients with FEP, which normalized in both regions following 4 weeks of antipsychotic treatment.

Alpha oscillations (8–14 Hz) are proposed to represent an active mechanism of functional inhibition of neuronal processing. Specifically, alpha oscillations are associated with pulses of inhibition repeating every ∼100 msec. Whether alpha phase, similar to alpha power, is under top–down control remains unclear. Moreover, the sources of such putative top–down phase control are unknown. We designed a cross-modal (visual/auditory) attention study in which we used magnetoencephalography to record the brain activity from 34 healthy participants. In each trial, a somatosensory cue indicated whether to attend to either the visual or auditory domain. The timing of the stimulus onset was predictable across trials. We found that, when visual information was attended, anticipatory alpha power was reduced in visual areas, whereas the phase adjusted just before the stimulus onset. Performance in each modality was predicted by the phase of the alpha oscillations previous to stimulus onset. Alpha oscillations in the left pFC appeared to lead the adjustment of alpha phase in visual areas. Finally, alpha phase modulated stimulus-induced gamma activity. Our results confirm that alpha phase can be top–down adjusted in anticipation of predictable stimuli and improve performance. Phase adjustment of the alpha rhythm might serve as a neurophysiological resource for optimizing visual processing when temporal predictions are possible and there is considerable competition between target and distracting stimuli.

Music represents a complex form of human cognition. To what extent our auditory system is attuned to music is yet to be clearly understood. Our principal aim was to determine whether the neurophysiological operations underlying pre-attentive auditory change detection (N1 enhancement (N1e)/Mismatch Negativity (MMN)) and the subsequent involuntary attentional reallocation (P3a) towards infrequent sound omissions, are influenced by differences in musical content. Specifically, we intended to explore any interaction effects that rhythmic and pitch dimensions of musical organization may have over these processes. Results showed that both the N1e and MMN amplitudes were differentially influenced by rhythm and pitch dimensions. MMN latencies were shorter for musical structures containing both features. This suggests some neurocognitive independence between pitch and rhythm domains, but also calls for further address on possible interactions between both of them at the level of early, automatic auditory detection. Furthermore, results demonstrate that the N1e reflects basic sensory memory processes. Lastly, we show that the involuntary switch of attention associated with the P3a reflects a general-purpose mechanism not modulated by musical features. Altogether, the N1e/MMN/P3a complex elicited by infrequent sound omissions revealed evidence of musical influence over early stages of auditory perception.

Detection of unexpected, yet relevant events is essential in daily life. fMRI studies have revealed the involvement of the ventral attention network (VAN), including the temporo‐parietal junction (TPJ), in such process. In this MEG study with 34 participants (17 women), we used a bimodal (visual/auditory) attention task to determine the neuronal dynamics associated with suppression of the activity of the VAN during top‐down attention and its recruitment when information from the unattended sensory modality is involuntarily integrated. We observed an anticipatory power increase of alpha/beta oscillations (12–20 Hz, previously associated with functional inhibition) in the VAN following a cue indicating the modality to attend. Stronger VAN power increases were associated with better task performance, suggesting that the VAN suppression prevents shifting attention to distractors. Moreover, the TPJ was synchronized with the frontal eye field in that frequency band, indicating that the dorsal attention network (DAN) might participate in such suppression. Furthermore, we found a 12–20 Hz power decrease and enhanced synchronization, in both the VAN and DAN, when information between sensory modalities was congruent, suggesting an involvement of these networks when attention is involuntarily enhanced due to multisensory integration. Our results show that effective multimodal attentional allocation includes the modulation of the VAN and DAN through upper‐alpha/beta oscillations. Altogether these results indicate that the suppressing role of alpha/beta oscillations might operate beyond sensory regions., Detection of unexpected, yet relevant events from multiple sensory sources is essential in daily life. We explored the dynamics of the ventral attention network (VAN), a set of brain regions related to the processing of unattended but salient stimuli, when relevant information was anticipated (i.e., during top‐down attention) and when unexpected congruent information from another sensory modality was presented (involuntary attentional enhancement). We report that activity in the alpha/beta range (12–20 Hz) within the VAN indexed both top‐down and attentional enhancement processes. In addition, the VAN was synchronized with the dorsal attention network in this frequency range, suggesting an integrated role of both networks for attentional regulation. Our results shed light on the neurophysiological mechanisms that the brain carry out for orienting attention to relevant environmental stimuli.

Involuntary attention allows for the detection and processing of novel and potentially relevant stimuli that lie outside of cognitive focus. These processes comprise change detection in sensory contexts, automatic orientation toward this change, and the selection of adaptive responses, including reorientation to the original goal in cases when the detected change is not relevant for task demands. These processes have been studied using the Event-Related Potential (ERP) technique and have been associated to the Mismatch Negativity (MMN), the P3a, and the Reorienting Negativity (RON) electrophysiological components, respectively. This has allowed for the objective evaluation of the impact of different neuropsychiatric pathologies on involuntary attention. Additionally, these ERP have been proposed as alternative measures for the early detection of disease and the tracking of its progression. The objective of this review was to integrate the results reported to date about MMN, P3a, and RON in different neurological and psychiatric disorders. We included experimental studies with clinical populations that reported at least two of these three components in the same experimental paradigm. Overall, involuntary attention seems to reflect the state of cognitive integrity in different pathologies in adults. However, if the main goal for these ERP is to consider them as biomarkers, more research about their pathophysiological specificity in each disorder is needed, as well as improvement in the general experimental conditions under which these components are elicited. Nevertheless, these ERP represent a valuable neurophysiological tool for early detection and follow-up of diverse clinical populations.

Although previous studies have shown that patients with multiple sclerosis (MS) may exhibit impaired decision making (DM), the specific neuro-cognitive processes that underlie this deficiency remain unknown. Inefficient DM may occur due to poor option assessment or a deficit in the evaluation of choice outcomes. This study uses, for the first time, the event-related potential (ERP) technique to analyze these DM subprocesses in patients with MS. Sixteen MS patients and nineteen control subjects performed a DM task based on the Iowa Gambling Task while a digital EEG was recorded. The P3b was analyzed as an index of option assessment, and both the feedback-related negativity (FRN) and P3b were considered markers for choice outcome evaluation. We found that MS patients made a larger number of unfavorable choices during the DM task (P = 0.02), with no differences between groups for reaction times. There were no significant differences in P3b for option assessment between the groups. In the control group, the type of feedback (gain, loss, or nothing) modified the FRN (F = 3.72, P = 0.033) and the P3b (F = 3.15, P = 0.059). This effect was not observed in the MS group. Also, FRN latencies were shorter in the MS group compared to controls (P = 0.047). Finally, lesions in temporal regions revealed by MRI were associated with DM both in behavioral and electrophysiological terms. We conclude that the DM impairment of patients with MS may be due to a deficit in their evaluation of choice outcomes or a general alteration in emotional reactivity.

This cohort study examines cognition in never-medicated individuals at different stages of the illness.

Background Cognitive impairment is a key feature of schizophrenia. While one recent study suggested that individuals with psychosis experience a progressive decline in certain cognitive domains during the first 10 years of their illness, other clinical and functional MRI-based studies have proposed that most cognitive deficits are present during the first episode and remain stable over time, possibly as a result of medication response. To examine the temporal nature of cognitive deficits in the schizophrenia spectrum, we examined cognition in never-medicated individuals at different stages of the illness. Methods We recruited three groups of patients: 1) individuals at clinical high-risk (CHR) for psychosis (n=87), 2) individuals experiencing their first-episode of a non-affective psychosis (FEP) (n=64) (defined by a duration of untreated psychosis < 74 weeks), and 3) individuals with chronic schizophrenia (n=40) (CSz – duration of untreated psychosis > 74 weeks). All three groups were antipsychotic-naïve. Patients with any comorbid disorders or current substance abuse disorders were excluded from this study. We also recruited matched healthy control subjects (n=102). All subjects were recruited at the Instituto Nacional de Neurología y Neurocirugía in Mexico City. The study was approved by the institutional review board. Adults provided written informed consent and minors provided assent with written consent provided by both parents. Cognition was assessed with the MATRICS Consensus Cognitive Battery. Differences between groups were analyzed using a repeated measures analysis of variance (RM-ANOVA) with cognitive domain as inter-subject factor and Bonferroni correction for post hoc pairwise comparisons. Statistical significance was set at p ≤ .05. Results Since age, gender, and parental education were significantly different between the groups, they were included as covariates in the RM-ANOVA. In this revised model, there was no main effect of age (p = 0.69) nor any interaction between age and any cognitive domain. Therefore, age was removed from the final model. We observed a significant main effect of group (p .99). We also found a significant group by cognitive domain interaction (p Within the FEP and CSz groups, no significant correlations were observed between duration of untreated psychosis and any cognitive domain. Discussion We observed significant cognitive deficits since at-risk stages of the schizophrenia spectrum. Patients with FEP were as impaired as those with CSz, while cognitive functioning observed in CHR individuals was intermediate between controls and patients with syndromal psychosis. These results emphasize the importance of pre-syndromal detection and prediction of burgeoning psychotic illness. Future research on strategies to mitigate the decline in cognitive function between presyndromal and first-episode psychosis is warranted.

Individuals with autism spectrum disorder (ASD) exhibit impaired adult facial processing, as shown by the N170 event-related potential. However, few studies explore such processing in mothers of children with ASD, and none has assessed the early processing of infant faces in these women. Moreover, whether processing of infant facial expressions in mothers of children with ASD is related to their response to their child's needs (maternal sensitivity [MS]) remains unknown. This study explored the N170 related to infant faces in a group of mothers of children with ASD (MA) and a reference group of mothers of children without ASD. For both emotional (crying, smiling) and neutral expressions, the MA group exhibited larger amplitudes of N170 in the right hemisphere, while the reference group showed similar interhemispheric amplitudes. This lateralization effect within the MA group was not present for nonfaces and was stronger in the mothers with higher MS. We propose that mothers of ASD children use specialized perceptual resources to process infant faces, and this specialization is mediated by MS. Our findings suggest that having an ASD child modulates mothers' early neurophysiological responsiveness to infant cues. Whether this modulation represents a biological marker or a response given by experience remains to be explored. Autism Research 2019, 12: 744-758. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: When mothers of children with autism spectrum disorder (ASD) see baby faces expressing emotions, they show a right-sided electrical response in the brain. This lateralization was stronger in mothers who were more sensitive to their children's needs. We conclude that having a child with ASD and being more attuned to their behavior generates a specialized pattern of brain activity when processing infant faces. Whether this pattern is biological or given by experience remains to be explored.

Objective The P3a is an event-related potential (ERP) associated with involuntary attention and dopaminergic function. As P3a is reduced at initial stages of Parkinson's disease (PD), our objective was to assess P3a as a possible marker of PD duration and severity. Methods Fifty-five patients were analyzed, 28 of which were at Hoehn and Yahr severity stage 1; 14 at stage 2; and 13 at stage 3. Seventeen patients were free of antiparkinsonian medication. PD duration was defined as the number of years between the onset of motor symptoms and the date of this study. Twenty-four healthy subjects were included as controls. An involuntary attention paradigm was administered while a digital EEG was obtained. Results The P3a amplitude was significantly lower in all PD groups compared to the control group ( F (3,75) =5.10, p =0.003), especially for stages 2 ( p =0.017) and 3 ( p =0.008). A regression analysis showed that the disease duration predicted inversely the P3a (Fz channel amplitude: Coefficient=−0.148, p =0.006; Frontocentral amplitude: Coefficient=−0.125, p =0.003) after controlling for demographic and clinical variables, medication, general cognitive state, and depression. Conclusions This is the first study reporting P3a sensibility to PD duration and severity. Significance This ERP could represent a reliable biomarker of the disease progression.

Event related potentials (ERP) associated with early sensory information processing have been proposed as possible vulnerability markers for psychosis. Compared to other ERPs reported in schizophrenia research, like Mismatch Negativity (MMN), little is known about P3a, an ERP related to novelty detection. The aim of this study was to analyze the MMN-P3a complex in 20 antipsychotic naive first-episode psychosis patients (FEP), 23 antipsychotic naive individuals at clinical high-risk for psychosis (CHR) and 24 healthy controls. The MMN-P3a amplitudes and latencies were obtained during a passive auditory mismatch frequency deviant ERP paradigm and analyzed in frontal and central scalp regions. There were no significant differences in MMN amplitude between groups. There was a significant group difference in P3a due to reduced amplitude (F[2,64] = 3.7, p = 0.03) in both CHR and FEP groups (Mean difference (MD) = 0.39, p = 0.04 and MD = 0.49, p = 0.02, respectively) compared to the control group and this effect was most prominent on the right side (Group × laterality effect: MD = 0.57, p < 0.01 and MD = 0.58, p < 0.01, respectively). No significant differences were observed for MMN or P3a latencies between groups. Although a P3a decrement in chronic schizophrenia and FEP has been previously reported, our results suggest that this novelty detection impairment is present even in pre-psychosis stages in antipsychotic naive subjects. This study supports the evidence that P3a could represent a neurophysiological vulnerability marker for the development of psychosis.

Manganese (Mn) is an essential metal, but in excess it becomes neurotoxic. Children's developing nervous system may be especially vulnerable to the neurotoxic effects of overexposure to this metal. The aim of this study was to assess the effect of Mn exposure on verbal memory and learning in 7- to 11-year-old children. We tested 79 children living in the Molango Mn-mining district and 95 children from a non-exposed community in the same State of Mexico. The Children's Auditory Verbal Learning Test (CAVLT) was administered. Blood and hair samples were obtained to determine Mn concentrations using atomic absorption spectrophotometry. CAVLT performance was compared between the two groups and multilevel regression models were constructed to estimate the association between biomarkers of Mn exposure and the CAVLT scores. The exposed group presented higher hair and blood Mn (p

Background Excessive exposure to manganese (Mn), an essential trace element, has been shown to be neurotoxic, especially when inhaled. Few studies have examined potential effects of Mn on cognitive functions of environmentally exposed children. Objective This study was intended to estimate environmental exposure to Mn resulting from mining and processing and to explore its association with intellectual function of school-age children. Methods Children between 7 and 11 years of age from the Molango mining district in central Mexico (n = 79) and communities with similar socioeconomic conditions that were outside the mining district (n = 93) participated in the cross-sectional evaluation. The revised version of the Wechsler Intelligence Scale for Children adapted for the Mexican population was applied. Concentrations of Mn in blood (MnB) and hair (MnH) were used as biomarkers of exposure. Results Exposed children had significantly higher median values for MnH (12.6 μg/g) and MnB (9.5 μg/L) than did nonexposed children (0.6 μg/g and 8.0 μg/L, respectively). MnH was inversely associated with Verbal IQ [β = −0.29; 95% confidence interval (CI), −0.51 to −0.08], Performance IQ (β = −0.08; 95% CI, −0.32 to 0.16), and Total Scale IQ (β = −0.20; 95% CI, −0.42 to 0.02). MnB was inversely but nonsignificantly associated with Total and Verbal IQ score. Age and sex significantly modified associations of MnH, with the strongest inverse associations in young girls and little evidence of associations in boys at any age. Associations with MnB did not appear to be modified by sex but appeared to be limited to younger study participants. Conclusions The findings from this study suggest that airborne Mn environmental exposure is inversely associated with intellectual function in young school-age children.

Complex movement (CM) refers to the representation of a goal-oriented action and is classified as either transitive (use of tools) or intransitive (communication gestures). Both types of CM have three specific components: temporal, spatial, and content, which are subdivided into specific error types (SET). Since there is debate regarding the contribution of each brain hemisphere for the types of CM, our objective was to describe the brain lateralization of components and SET of transitive and intransitive CM. We studied 14 patients with a left hemisphere stroke (LH), 12 patients with a right hemisphere stroke (RH), and 16 control subjects. The Florida Apraxia Screening Test-Revised (FAST-R, Rothi et al., 1988) was used for the assessment of CM. Both clinical groups showed a worse performance than the control group on the total FAST-R and transitive movement scores (p

To describe, in a Mexican sample of urban and rural residents older than 65 years, with and without dementia, the frequency and severity of neuropsychiatric symptoms.This work is part of the multi-center, epidemiological study carried out by the 10/66 Dementia Research Group, with 1,003 subjects from an urban region and 1,000 subjects from a rural region. Neuropsychiatric symptoms were assessed with the abbreviated version of the Neuropsychiatric Inventory (NPI-Q).Eighty six and eighty five dementia cases were found in the urban and rural regions, respectively. Subjects with dementia were more frequently widows, older and less educated, and the ones from the rural region had fewer neuropsychiatric symptoms, compared to the urban region. In both regions all symptoms were more severe in subjects with dementia. A high frequency of affective symptoms (depression and apathy specially) was observed, and irritability and anxiety in second term. The caregiver stress levels were associated with the frequency and severity of symptoms.This is the first study reporting neuropsychiatric symptoms associated with dementia identified by means of culturally validated and population based diagnostic criteria, in Mexican residents of urban and rural settings.

Early studies on manganese (Mn) exposure have shown that this transition metal affects dopamine neurotransmission. Dopamine serves as a tonic inhibitor of prolactin release in the anterior hypophysis, thus the serum prolactin levels in occupationally Mn exposed workers has been found increased. However, little is known about environmental Mn exposure effect on this hormone. In the present study we assessed serum prolactin in environmentally (mainly through air) exposed children living in the proximity of a rich Mn zone in Mexico and a control group with similar socioeconomic and ethnic characteristics. We also determined Mn levels in blood and hair, hemoglobin and anthropometric variables. Children between 7 and 11 years old were included (77 from Mn exposed and 93 from control communities). Blood Mn was higher in exposed children (median 9.5 μg/L, rank [5.5, 18]) as compared to the control group (median 8 μg/L, rank [5, 14]) (p

Objectives Occupational manganese (Mn) exposure has been associated with motor deficits in adult workers, but data on the potential effects of environmental exposure to Mn on the developing motor function for a children population is scarce. The aim of this study was to evaluate the association between exposure to Mn and motor function of school aged children. Methods We conducted a cross-sectional study selecting 195 children (100 exposed and 95 unexposed) between 7 and 11 years old. The following tests were used to evaluate the motor function: Grooved pegboard, finger tapping, and Santa Ana test. Mn exposure was assessed by blood (MnB) and hair concentrations (MnH). We constructed linear regression models to evaluate the association between exposure to Mn and the different test scores adjusting for age, sex, maternal education, hemoglobin and blood lead. Results The median concentration of MnH and MnB was significantly higher in exposed (12.6 μg/g and 9.5 μg/L) compared to unexposed children (0.6 μg/g and 8.0 μg/L). The exposed children on average performed the grooved pegboard test faster, but made more errors, although these results did not reach statistical significance with neither one of the Mn exposure biomarkers. MnB showed an inverse association on the execution of the finger tapping test (average in 5 trials β −0.4, p = 0.02), but no association was observed with MnH. Conclusions A subtle negative association of Mn exposure on motor speed and coordination was shown. In adults, the main effect of environmental Mn exposure has been associated with motor skills, but these results suggest that such alterations are not the main effect on children.

We examined the association between non-occupational exposure to Mn and cognitive functions. The study was carried out in a mining district located in Hidalgo State, Mexico, with 288 adults. Air and blood Mn concentrations were determined, and neuropsychological tests were administered to explore cognitive functions and depression. Blood Mn mean was 9.5 ± 4.14 μg/L. A total of 73% of the study group were in contact with air Mn levels that surpassed the EPA recommended guideline level for non-occupational environments (0.05 μg/m(3)). Air Mn concentration was associated as a risk factor for attention impairment (OR=1.75, 95% CI: 1.01-3.06). Blood Mn levels were not associated to any of the measured outcomes. The main finding of this study is the presence of attention impairments associated to high levels of air Mn exposure. These results confirm previous studies, in which cognitive impairment is reported for exposed population.

Background: Dysregulations of the major inhibitory and excitatory amino neurotransmitter systems of γ-aminobutyric acid and glutamate, respectively, have been described in patients with schizophrenia. However, it is unclear whether these abnormalities are present in subjects at ultra-high risk for psychosis. Methods: Twenty-three antipsychotic naive subjects at ultra-high risk and 24 healthy control subjects, matched for age, sex, handedness, cigarette smoking, and parental education, underwent proton magnetic resonance spectroscopy scans in the dorsal caudate bilaterally and the medial prefrontal cortex at 3T. Levels of γ-aminobutyric acid and of the combined resonance of glutamate and glutamine (Glx) were obtained using the standard J-editing technique and expressed as peak area ratios relative to the synchronously acquired unsuppressed voxel water signal. Results: Higher levels of γ-aminobutyric acid ( P