Interaction between catechol-O-methyltransferase Val/Met polymorphism and cognitive reserve for negative symptoms in schizophrenia

BACKGROUND Cognitive reserve(CR)and the catechol-O-methyltransferase(COMT)Val/Met polymorphism are reportedly linked to negative symptoms in schizophrenia.However,the regulatory effect of the COMT genotype on the relationship between CR and negative symptoms is still unexamined.AIM To investigate whether the relationship between CR and negative symptoms could be regulated by the COMT Val/Met polymorphism.METHODS In a cross-sectional study,54 clinically stable patients with schizophrenia underwent assessments for the COMT genotype,CR,and negative symptoms.CR was estimated using scores in the information and similarities subtests of a short form of the Chinese version of the Wechsler Adult Intelligence Scale.RESULTS COMT Met-carriers exhibited fewer negative symptoms than Val homozygotes.In the total sample,significant negative correlations were found between negative symptoms and information,similarities.Associations between information,similarities and negative symptoms were observed in Val homozygotes only,with information and similarities showing interaction effects with the COMT genotype in relation to negative symptoms(information,β=-0.282,95%CI:-0.552 to-0.011,P=0.042;similarities,β=-0.250,95%CI:-0.495 to-0.004,P=0.046).CONCLUSION This study provides initial evidence that the association between negative symptoms and CR is under the regulation of the COMT genotype in schizophrenia.

Influences of Age and Length of Education on rCBF-SPECT in Healthy Elderly:Diagnostic Implications for Dementia

Background: Few previous studies have described other than age- and gender related changes in regional cerebral blood flow (rCBF) in healthy elderly. What is the influence of other common clinically relevant variables such as ache, education, MMSE, and smoking history? Purpose: To study rCBF in Swedish healthy elderly by single-photon emission computed tomography (SPECT) and evaluate the influence on rCBF of age, gender, education, MMSE, ache, and smoking with a focus on education in relation to the ‘cognitive reserve’. Methods: Healthy subjects (n = 45, 50 -75 y), sampled from a large longitudinal aging study took part in an extensive examination of health and memory, including cognitive testing and socio-economic survey. After injection of 99 mTc-hexamethylpropylene amine oxime (HMPAO) followed by SPECT the rCBF-SPECT images were analyzed using statistical parametric mapping (SPM). Results: Age-related decreases in uptake were seen in interhemispheric and interlobar regions. There was a positive rCBF correlation with education in the inferior frontal lobe and a higher uptake in the left temporal lobe in an age-gender-matched high education subgroup. Conclusion: The localization of the age related findings except for the medial temporal lobe differs markedly from typical dementia related findings. A reduction close to interhemispheric or interlobar space should always be related to chronological age. Education seems to have an influence on basal brain function at a resting-state condition. Knowledge of normal rCBF variations for variables such as age and education should be considered when making clinical diagnosis. The findings could be interpreted as further support for the theory of cognitive reserve.

Mild cognitive impairment in Parkinson’s disease:a distinct clinical entity?

Background:Mild cognitive impairment in Parkinson’s disease(PD-MCI)is a common clinical condition.Understanding its pathology and clinical features is important for early intervention before the onset of dementia.In the past,variable definitions and differences in neuropsychological batteries generated divergent results of the affected cognitive patterns.Main body:The introduction of PD-MCI criteria by the Movement Disorders Society(MDS)Task Force provides a more uniform system for defining and measuring PD-MCI and may improve the validity of future research.PD-MCI is likely to be heterogeneous since it can coexist with Alzheimer’s disease and/or Lewy body pathologies in PD.Pathogeneses of neuropsychiatric disturbances,such as depression,anxiety and apathy,are associated with PD with or without MCI.In addition,cognitive reserve formed by patients’unique life experiences may influence the outward cognitive performance despite the presence of the aforementioned pathogeneses and hence alter the diagnosis of MCI.Conclusion:The overlap of cognitive impairment across different neurodegenerative diseases suggests that PD-MCI is likely to result from a mixture of complex pathophysiologies,rather than being a distinct pathologic entity.Differentiating MCI from other organic symptoms in PD would facilitate novel therapeutic strategies.

Resting-state functional connectivity in lifelong musicians

Background:It has been postulated that musicianship can lead to enhanced brain and cognitive reserve,but the neural mechanisms of this effect have been poorly understood.Lifelong professional musicianship in conjunction with novel brain imaging techniques offers a unique opportunity to examine brain network differences between musicians and matched controls.Objective:In this study we aim to investigate how resting-state functional networks(FNs)manifest in lifelong active musicians.We will evaluate the FNs of lifelong musicians and matched healthy controls using resting-state functional magnetic resonance imaging.Methods:We derive FNs using the data-driven independent component analysis approach and analyze the functional network con-nectivity(FNC)between the default mode(DMN),sensory-motor(SMN),visual(VSN),and auditory(AUN)networks.We examine whether the linear regressions between FNC and age are different between the musicians and the control group.Results:The age trajectory of average FNC across all six pairs of FNs shows significant differences between musicians and controls.Musicians show an increase in average FNC with age while controls show a decrease(P=0.013).When we evaluated each pair of FN,we note that in musicians FNC values increased with age in DMN–AUN,DMN–VSN,and SMN–VSN and in controls FNC values decreased with age in DMN–AUN,DMN–SMN,AUN–SMN,and SMN–VSN.Conclusion:This result provides early evidence that lifelong musicianship may contribute to enhanced brain and cognitive reserve.Results of this study are preliminary and need to be replicated with a larger number of participants.