The nature of prospective memory deficit in patients with obsessive-compulsive disorder.

We comprehensively examined prospective memory (PM) performance in patients with obsessive-compulsive disorder (OCD), and explored the cognitive and psychopathological correlates of PM in this clinical population. Fifty-eight OCD patients and 58 healthy controls were assessed with computer-based PM tasks and related neurocognitive functions, and the participants also reported frequency of PM failures and compulsive behaviours in daily life. OCD patients had intact activity-based PM performance but had lower accuracy in time-based PM and longer reaction time to event-based PM cues compared to healthy controls. Among the neurocognitive functions, both the WCST (perseverative error) and the letter number span correlated with time-based PM. OCD patients reported similar number of PM failures in daily life as controls, which correlated with their intact event-based PM performance, suggesting a generally good insight into their PM functions. Neither clinician-assessed nor self-reported OCD symptoms correlated with PM performance. This study indicates that PM impairment tends to vary with the PM cue types in OCD patients. In addition, certain executive functions (i.e., mental shifting and updating) may contribute to time-based PM impairment in patients with OCD.

Graph theoretical analysis of sedation's effect on whole brain functional system in school-aged children.

The neurophysiological mechanism underlying sedation, especially in school-aged children, remains largely unknown. The recently emerged resting-state functional magnetic resonance imaging (rsfMRI) technique, capable of delineating brain's functional interaction pattern among distributed brain areas, proves to be a unique and powerful tool to study sedation-induced brain reorganization. Based on a relatively large school-aged children population (n=28, 10.3±2.6 years, range 7-15 years) and leveraging rsfMRI and graph theoretical analysis, this study aims to delineate sedation-induced changes in brain's information transferring property from a whole brain system perspective. Our results show a global deterioration in brain's efficiency properties (p=0.0085 and 0.0018, for global and local efficiency, respectively) with a locally graded distribution featuring significant disruptions of key consciousness-related regions. Moreover, our results also indicate a redistribution of brain's information-processing hubs characterized by a right and posterior shift as consistent with the reduced level of consciousness during sedation. Overall, our findings inform a sedation-induced functional reorganization pattern in school-aged children that greatly improve our understanding of sedation's effect in children and may potentially serve as reference for future sedation-related experimental studies and clinical applications.

Identification of MCI using optimal sparse MAR modeled effective connectivity networks.

Capability of detecting causal or effective connectivity from resting-state functional magnetic resonance imaging (R-fMRI) is highly desirable for better understanding the cooperative nature of the brain. Effective connectivity provides specific dynamic temporal information of R-fMRI time series and reflects the directional causal influence of one brain region over another. These causal influences among brain regions are normally extracted based on the concept of Granger causality. Conventionally, the effective connectivity is inferred using multivariate autoregressive (MAR) modeling with default model order q = 1, considering low frequency fluctuation of R-fMRI time series. This assumption, although reduces the modeling complexity, does not guarantee the best fitting of R-fMRI time series at different brain regions. Instead of using the default model order, we propose to estimate the optimal model order based upon MAR order distribution to better characterize these causal influences at each brain region. Due to sparse nature of brain connectivity networks, an orthogonal least square (OLS) regression algorithm is incorporated to MAR modeling to minimize spurious effective connectivity. Effective connectivity networks inferred using the proposed optimal sparse MAR modeling are applied to Mild Cognitive Impairment (MCI) identification and obtained promising results, demonstrating the importance of using optimal causal relationships between brain regions for neurodegeneration disorder identification.

Neurological soft signs in obsessive-compulsive disorder: the effect of co-morbid psychosis and evidence for familiality.

Patients with obsessive-compulsive disorder (OCD) have increased rates of neurological soft signs (NSS) when compared to healthy controls. However, previous findings have been confounded by the presence of co-morbidity with disorders themselves associated with increased NSS, such as schizophrenia. Moreover, it remains unclear whether NSS in OCD reflect a vulnerability to this disorder. This study aimed to examine: 1) the severity of NSS in patients with OCD alone, in patients with OCD and co-morbid psychosis (schizophrenia or bipolar disorders), and in healthy controls; and b) whether unaffected first-degree relatives of patients with OCD also demonstrate a higher prevalence rate of NSS than healthy controls. NSS were assessed with the Cambridge Neurological Inventory (CNI) in 100 patients with OCD, 38 patients with OCD and psychosis (22 with bipolar disorders and 16 with schizophrenia), and 101 healthy controls. Forty-seven unaffected first-degree relatives of patients with OCD only were also administered the CNI. Patients with OCD showed significantly higher scores in motor coordination and total NSS than controls, and patients with OCD co-morbid with psychosis also showed significantly higher scores in motor coordination and total NSS than controls. Although there were no differences in NSS between patients with OCD only and OCD and psychosis as a whole, patients with OCD co-morbid with schizophrenia showed significantly higher scores in motor coordination than patients with OCD, patients with OCD and bipolar disorder, and healthy controls. Unaffected first-degree relatives only showed a higher prevalence rate than healthy controls in specific motor coordination signs, such as Opposition and Extinction. These findings suggest that patients with OCD exhibit more NSS than healthy controls, and that motor coordination signs may be even more extensive when OCD is co-morbid with psychosis. Some of these abnormalities may be indicative of a vulnerability to these disorders, as indicated by their presence in un-affected first-degree relatives.

The Chinese version of the Obsessive-Compulsive Inventory-Revised scale: replication and extension to non-clinical and clinical individuals with OCD symptoms.

BACKGROUND: The Obsessive-Compulsive Inventory-Revised (OCI-R) was designed to evaluate the severity of obsessive-compulsive symptoms in both clinical and non-clinical samples. The aim of the study was to evaluate the psychometric properties of a Chinese version of this scale. METHODS: The Chinese version of the OCI-R was administered to both a non-clinical sample (209 undergraduate students) and a clinical sample (56 obsessive-compulsive disorder (OCD) patients). Confirmatory factor analysis was conducted to examine the construct validity of the OCI-R in the non-clinical sample. The internal consistency at baseline and test-retest reliabilities at 4-week interval was examined in both the non-clinical and clinical samples. RESULTS: The confirmatory factor analysis of the non-clinical sample confirmed a 6-factor model suggested by the original authors of the instrument (df = 120, RMSEA = 0.068, CFI = 0.88, NNFI = 0.85, GFI = 0.89). The internal consistency and test-retest reliability were at an acceptable range for both the non-clinical and clinical samples. The OCI-R also showed good clinical discrimination for patients with OCD from healthy controls. CONCLUSIONS: The Chinese version of the OCI-R is a valid and reliable instrument for measuring OCD symptoms in the Chinese context.

[Prevalence of internet addiction and the related factors in middle school students in Guangzhou].

OBJECTIVE: To study the status of and the factors contributing to Internet addiction among middle school students in Guangzhou. METHODS: Cluster sampling method was used to recruit an urban middle school, a rural junior middle school and a rural senior high school to conduct the survey with the stressful life event questionnaire, the trait-oriented coping styles questionnaire and the Internet Addiction Test. RESULTS: The majority of respondents were classified as normal users of the Internet (n=1392, 89.2%), with 158 (10.2%) moderately and 10 (0.6%) severely addicted to the Internet. Fifty-eight students had never used the Internet. There were significant differences in gender, the father's education, the 4 dimensions of the stressful life event questionnaire and the coping styles between students with and without Internet addiction. Binary logistic analysis showed that the factors contributing to Internet addiction included passive coping styles, male gender and stressful life event experienced in family and interpersonal communication. CONCLUSIONS: The incidence of Internet addiction is high among middle school students in Guangzhou. Male students with stressful life events in family and interpersonal communication, poor education on the part of the father, and frequent use of negative coping styles are more likely to develop Internet addiction.

Effect of pathological use of the internet on adolescent mental health: a prospective study.

OBJECTIVE: To examine the effect of pathological use of the Internet on the mental health, including anxiety and depression, of adolescents in China. It is hypothesized that pathological use of the Internet is detrimental to adolescents' mental health. DESIGN: A prospective study with a randomly generated cohort from the population. SETTING: High schools in Guangzhou, China. PARTICIPANTS: Adolescents aged between 13 and 18 years. MAIN EXPOSURE: Pathological use of the Internet was assessed using the Pathological Use of the Internet Test. OUTCOME MEASURES: Depression and anxiety were assessed by the Zung Depression and Anxiety Scales. RESULTS: After adjusting for potential confounding factors, the relative risk of depression for those who used the Internet pathologically was about 21/2 times (incidence rate ratio,2.5;95%confidence interval,1.3-4.3) that of those who did not exhibit the targeted pathological internet use behaviors. No significant relationship between pathological use of the Internet and anxiety at follow-up was observed. CONCLUSIONS: Results suggested that young people who are initially free of mental health problems but use the Internet pathologically could develop depression as a consequence. These results have direct implications for the prevention of mental illness in young people, particularly in developing countries.

Factors associated with Internet addiction among adolescents.

This research examined factors associated with Internet addiction in adolescence using a population-based cross-sectional survey with self-reported questionnaires. Participants were recruited from high school students, ages 13 to 18 years, registered on the secondary school registry in Guangzhou city using a stratified random sampling technique. Internet addiction was assessed using the Internet Addiction Test (IAT). Information was also collected on demographics, health behaviors, and perception of personal condition. Depression was assessed by the Zung Self-Rating Depression Scale. The majority of respondents were classified as normal users of the Internet (n = 1,392, 89.2%), with 158 (10.2%) moderately and 10 (0.6%) severely addicted to the Internet. Results from the multivariate logistic regression analyses suggested a 50% increased odds for males to be addicted to the Internet (OR = 1.5, 95% CI = 1.1-2.2) when compared to females. Other potential risk factors included drinking behavior (OR = 1.7, 95% CI = 1.1-2.8), family dissatisfaction (OR = 2.4, 95% CI = 1.3-4.3), and experience of recent stressful events (OR = 10.0, 95% CI = 6.5-12.2). Stress-related variables were associated with Internet addiction among adolescents as they are also related to other addictions. Clinicians need to be aware of potential comorbidities of other problems such as stress and family dissatisfaction among adolescent Internet addiction patients.

Cryptochrome1 maybe a candidate gene of schizophrenia.

During the last 10 years, we have witnessed major progress in the genetic study of schizophrenia, but gene-mapping efforts have been hampered by the complex mode of inheritance and the likelihood of multiple genes of small effect. In view of the complexity, it may be instructive to understand the biological bases for pathogenesis. Extensive disruption in circadian function is known to occur among schizophrenia patients. If circadian dysfunction can be established as an 'endophenotype' for schizophrenia, it may not only enable the identification of more homogenous sub-groups, but also facilitate the genetic analyses. Therefore, circadian dysfunction maybe underlies the pathogenesis of schizophrenia and would be logical to investigate polymorphisms of genes encoding key proteins that mediate circadian rhythms. Cryptochrome1 (Cry1), located in a chromosomal region 12q23-q24.1, performs predominantly regulatory function in circadian clock and which is close to a linkage hotspot (12q24) of schizophrenia. Recent studies also found that Cry1 gene interacted with antipsychotic drugs and dopamine system which played a core role in the pathophysiology of schizophrenia. Based on these findings, we speculate that Cry1 was the candidate gene of schizophrenia. The proposition may have new clues on the development of genetic study on complex diseases.

MR diffusion-weighed imaging of rabbit liver.

AIM: To study the techniques of MR diffusion-weighed imaging (DWI) for normal rabbit liver. METHODS: After 15 normal New Zealand white rabbits and one New Zealand white rabbit implanted with VX-2 tumor were anesthetized with 3% soluble pentobarbitone, DWI was performed respectively for different b values, repetition times (TR) or thicknesses, when other parameters were the same and magnetic resonance imaging (MRI) was performed respectively, or with different field of views (FOV) or coil when other parameters were the same. The distinction between groups was analyzed by SPSS10.0 with apparent diffusion coefficient (ADC), quality index (QI) or signal-noise ratio (SNR). RESULTS: As b value increased, liver ADC, QI and SNR of DWI became smaller and simultaneously (F = 292.87, 156.1, 88.23, P<0.01). QI of DWI was high, when b value was 10, 50 or 100 respectively, but the distinction between them was insignificant; when b value was 800, QI and SNR of DWI were low. QI and SNR of DWI had no significant difference between TR = 4 000, 6 000 and 8 000. QI of DWI with 2 mm thickness was bigger than that with 5 mm thickness (t = 3.04, P<0.01), but SNR of DWI with 2 mm thickness was significantly smaller (t = -17.86, P<0.01). SNR of MRI with knee joint coil was obviously bigger than that with cranium coil (t = -5.77 (T1WI) or -4.02 (T2WI), P<0.01), but QI of MRI was smaller on the contrary (t = 7.10 (T1WI) or 3.97 (T2WI), P<0.01). When FOV was enlarged gradually, SNR of MRI increased (F = 85.81 (T1WI) or 221.96 (T2WI), P<0.01), but QI firstly increased, then decreased (F = 68.67 (T1WI) or 69.46 (T2WI), P<0.01) and QI of MRI was the biggest when FOV was 20 cm x 15 cm. CONCLUSION: The scanning technique is very important in DWI of rabbit liver and the overall quality of DWI with b (100 s/mm2), thickness (2 mm), cranium coils and FOV (20 cm x 15 cm) was best in our study, when other parameters were the same.