Neuropsychiatric symptoms and brain morphology in patients with mild cognitive impairment, cerebrovascular disease and Parkinson disease: A cross sectional and longitudinal study.

OBJECTIVES: Neuropsychiatric symptoms (NPS) increase risk of developing dementia and are linked to various neurodegenerative conditions, including mild cognitive impairment (MCI due to Alzheimer's disease [AD]), cerebrovascular disease (CVD), and Parkinson's disease (PD). We explored the structural neural correlates of NPS cross-sectionally and longitudinally across various neurodegenerative diagnoses. METHODS: The study included individuals with MCI due to AD, (n = 74), CVD (n = 143), and PD (n = 137) at baseline, and at 2-years follow-up (MCI due to AD, n = 37, CVD n = 103, and PD n = 84). We assessed the severity of NPS using the Neuropsychiatric Inventory Questionnaire. For brain structure we included cortical thickness and subcortical volume of predefined regions of interest associated with corticolimbic and frontal-executive circuits. RESULTS: Cross-sectional analysis revealed significant negative correlations between appetite with both circuits in the MCI and CVD groups, while apathy was associated with these circuits in both the MCI and PD groups. Longitudinally, changes in apathy scores in the MCI group were negatively linked to the changes of the frontal-executive circuit. In the CVD group, changes in agitation and nighttime behavior were negatively associated with the corticolimbic and frontal-executive circuits, respectively. In the PD group, changes in disinhibition and apathy were positively associated with the corticolimbic and frontal-executive circuits, respectively. CONCLUSIONS: The observed correlations suggest that underlying pathological changes in the brain may contribute to alterations in neural activity associated with MBI. Notably, the difference between cross-sectional and longitudinal results indicates the necessity of conducting longitudinal studies for reproducible findings and drawing robust inferences.

White matter hyperintensity burden predicts cognitive but not motor decline in Parkinson's disease: results from the Ontario Neurodegenerative Diseases Research Initiative.

BACKGROUND AND PURPOSE: The pathophysiology of Parkinson's disease (PD) negatively affects brain network connectivity, and in the presence of brain white matter hyperintensities (WMHs) cognitive and motor impairments seem to be aggravated. However, the role of WMHs in predicting accelerating symptom worsening remains controversial. The objective was to investigate whether location and segmental brain WMH burden at baseline predict cognitive and motor declines in PD after 2 years. METHODS: Ninety-eight older adults followed longitudinally from Ontario Neurodegenerative Diseases Research Initiative with PD of 3-8 years in duration were included. Percentages of WMH volumes at baseline were calculated by location (deep and periventricular) and by brain region (frontal, temporal, parietal, occipital lobes and basal ganglia + thalamus). Cognitive and motor changes were assessed from baseline to 2-year follow-up. Specifically, global cognition, attention, executive function, memory, visuospatial abilities and language were assessed as were motor symptoms evaluated using the Movement Disorder Society Unified Parkinson's Disease Rating Scale Part III, spatial-temporal gait variables, Freezing of Gait Questionnaire and Activities Specific Balance Confidence Scale. RESULTS: Regression analysis adjusted for potential confounders showed that total and periventricular WMHs at baseline predicted decline in global cognition (p < 0.05). Also, total WMH burden predicted the decline of executive function (p < 0.05). Occipital WMH volumes also predicted decline in global cognition, visuomotor attention and visuospatial memory declines (p < 0.05). WMH volumes at baseline did not predict motor decline. CONCLUSION: White matter hyperintensity burden at baseline predicted cognitive but not motor decline in early to mid-stage PD. The motor decline observed after 2 years in these older adults with PD is probably related to the primary neurodegenerative process than comorbid white matter pathology.

Neuropsychiatric Symptom Burden across Neurodegenerative Disorders and its Association with Function.

OBJECTIVE: Neuropsychiatric symptoms (NPS) are prevalent in neurodegenerative disorders, however, their frequency and impact on function across different disorders is not well understood. We compared the frequency and severity of NPS across Alzheimer's disease (AD) (either with mild cognitive impairment or dementia), Cerebrovascular disease (CVD), Parkinson's disease (PD), frontotemporal dementia (FTD), and amyotrophic lateral sclerosis (ALS), and explored the association between NPS burden and function. METHODS: We obtained data from Ontario Neurodegenerative Disease Research Initiative (ONDRI) that included following cohorts: AD (N = 111), CVD (N = 148), PD (N = 136), FTD (N = 50) and ALS (N = 36). We compared the frequency and severity of individual NPS (assessed by the neuropsychiatric inventory questionnaire) across cohorts using generalized estimating equations and analysis of variance. Second, we assessed the relationship of NPS burden with instrumental (iADLs) and basic (ADLs) activities of living across cohorts using multivariate linear regression while adjusting for relevant demographic and clinical covariates. RESULTS: Frequency of NPS varied across cohorts (χ2(4) = 34.4, p < .001), with post-hoc tests showing that FTD had the greatest frequency as compared to all other cohorts. The FTD cohort also had the greatest severity of NPS (H(4) = 34.5, p < .001). Further, there were differences among cohorts in terms of the association between NPS burden and ADLs (F(4,461) = 3.1, p = 0.02). Post-hoc comparisons suggested that this finding was driven by the FTD group, however, the differences did not remain significant following Bonferroni correction. There were no differences among cohorts in terms of the association between NPS burden and IADLs. CONCLUSIONS: NPS frequency and severity are markedly greater in FTD as compared to other neurodegenerative diseases. Further, NPS burden appears to be associated differently with function across neurodegenerative disorders, highlighting the need for individualized clinical interventions.

Rare neurovascular genetic and imaging markers across neurodegenerative diseases.

INTRODUCTION: Cerebral small vessel disease (SVD) is common in patients with cognitive impairment and neurodegenerative diseases such as Alzheimer's and Parkinson's. This study investigated the burden of magnetic resonance imaging (MRI)-based markers of SVD in patients with neurodegenerative diseases as a function of rare genetic variant carrier status. METHODS: The Ontario Neurodegenerative Disease Research Initiative study included 520 participants, recruited from 14 tertiary care centers, diagnosed with various neurodegenerative diseases and determined the carrier status of rare non-synonymous variants in five genes (ABCC6, COL4A1/COL4A2, NOTCH3/HTRA1). RESULTS: NOTCH3/HTRA1 were found to significantly influence SVD neuroimaging outcomes; however, the mechanisms by which these variants contribute to disease progression or worsen clinical correlates are not yet understood. DISCUSSION: Further studies are needed to develop genetic and imaging neurovascular markers to enhance our understanding of their potential contribution to neurodegenerative diseases.

Pharmacological treatment for attention deficit hyperactivity disorder (ADHD) in children with comorbid tic disorders.

BACKGROUND: This is an update of the original Cochrane Review published in Issue 4, 2011.Attention deficit hyperactivity disorder (ADHD) is the most prevalent of the comorbid psychiatric disorders that complicate tic disorders. Medications commonly used to treat ADHD symptoms include stimulants such as methylphenidate and amphetamine; non-stimulants, such as atomoxetine; tricyclic antidepressants; and alpha agonists. Alpha agonists are also used as a treatment for tics. Due to the impact of ADHD symptoms on the child with tic disorder, treatment of ADHD is often of greater priority than the medical management of tics. However, for many decades, clinicians have been reluctant to use stimulants to treat children with ADHD and tics for fear of worsening their tics.  OBJECTIVES: To assess the effects of pharmacological treatments for ADHD in children with comorbid tic disorders on symptoms of ADHD and tics. SEARCH METHODS: In September 2017, we searched CENTRAL, MEDLINE, Embase, and 12 other databases. We also searched two trial registers and contacted experts in the field for any ongoing or unpublished studies. SELECTION CRITERIA: We included randomized, double-blind, controlled trials of any pharmacological treatment for ADHD used specifically in children with comorbid tic disorders. We included both parallel-group and cross-over study designs. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures of Cochrane, in that two review authors independently selected studies, extracted data using standardized forms, assessed risk of bias, and graded the overall quality of the evidence by using the GRADE approach. MAIN RESULTS: We included eight randomized controlled trials (four of which were cross-over trials) with 510 participants (443 boys, 67 girls) in this review. Participants in these studies were children with both ADHD and a chronic tic disorder. All studies took place in the USA and ranged from three to 22 weeks in duration. Five of the eight studies were funded by charitable organizations or government agencies, or both. One study was funded by the drug manufacturer. The other two studies did not specify the source of funding. Risk of bias of included studies was low for blinding; low or unclear for random sequence generation, allocation concealment, and attrition bias; and low or high for selective outcome reporting. We were unable to combine any of the studies in a meta-analysis due to important clinical heterogeneity and unit-of-analysis issues.Several of the trials assessed multiple agents. Medications assessed included methylphenidate, clonidine, desipramine, dextroamphetamine, guanfacine, atomoxetine, and deprenyl. There was low-quality evidence for methylphenidate, atomoxetine, and clonidine, and very low-quality evidence for desipramine, dextroamphetamine, guanfacine and deprenyl in the treatment of ADHD in children with tics. All studies, with the exception of a study using deprenyl, reported improvement in symptoms of ADHD. Tic symptoms also improved in children treated with guanfacine, desipramine, methylphenidate, clonidine, and a combination of methylphenidate and clonidine. In one study, tics limited further dosage increases of methylphenidate. High-dose dextroamphetamine appeared to worsen tics in one study, although the length of this study was limited to three weeks. There was appetite suppression or weight loss in association with methylphenidate, dextroamphetamine, atomoxetine, and desipramine. There was insomnia associated with methylphenidate and dextroamphetamine, and sedation associated with clonidine. AUTHORS' CONCLUSIONS: Following an updated search of potentially relevant studies, we found no new studies that matched our inclusion criteria and thus our conclusions have not changed.Methylphenidate, clonidine, guanfacine, desipramine, and atomoxetine appear to reduce ADHD symptoms in children with tics though the quality of the available evidence was low to very low. Although stimulants have not been shown to worsen tics in most people with tic disorders, they may, nonetheless, exacerbate tics in individual cases. In these instances, treatment with alpha agonists or atomoxetine may be an alternative. Although there is evidence that desipramine may improve tics and ADHD in children, safety concerns will likely continue to limit its use in this population.

Prevalence of Surgical Site Infections Following Orthognathic Surgery: A Double-Blind, Randomized Controlled Trial on a 3-Day Versus 1-Day Postoperative Antibiotic Regimen.

PURPOSE: The purpose of this study was to determine the effect of a 3- versus 1-day antibiotic regimen on the rate of surgical site infection (SSI) in patients undergoing orthognathic surgery at a department of oral and maxillofacial surgery in Halifax, Nova Scotia, Canada. MATERIALS AND METHODS: A prospective, randomized controlled trial was conducted. All patients received 1 day of intravenous antibiotics after surgery. Then, patients were randomly distributed into groups that received 2 days of additional antibiotics (group A) or placebo (group B). The primary outcome measured was the presence of SSI. The operating surgeon, concomitant extraction of teeth, surgical procedures performed, duration of intermaxillary fixation, and length of hospital stay were analyzed for an effect on SSI. Patients were followed for 1 year after surgery to identify SSIs that might have been diagnosed outside the hospital. RESULTS: The trial started with 288 patients, and 117 patients were lost to follow-up. Statistical analyses were ultimately performed on those 171 patients who were adherent to the study medication regimen. Group A (n = 86) and B (n = 85) SSI rates were 7.0 and 17.6% (number needed to treat = 10; P = .04), respectively. Mandibular bilateral sagittal split osteotomy (BSSO) was involved in 71% of SSIs. Intra- and postoperative surgical variables did not have a relevant effect on the SSI rate. Patients were followed for 1 year after surgery, and group A (n = 46) and group B (n = 44) had SSI rates of 4 and 25% (P < .05), respectively. CONCLUSIONS: Three days of postoperative cefazolin and cephalexin markedly decreases SSI rates compared with 1 day. However, the number needed to treat of 10 suggests that the benefits of the extended regimen might not outweigh the risks. The high prevalence of SSIs at the mandibular BSSO incisions might have been caused by contamination, with more saliva and reception of a lower blood supply, than maxillary Le Fort I incisions. Mandibular osteotomies could benefit from an extended antibiotic regimen to minimize SSIs and associated complications. Other surgical variables might not require special consideration for antibiotic therapy.

Characterization of a protein-protein interaction within the SigO-RsoA two-subunit σ factor: the σ70 region 2.3-like segment of RsoA mediates interaction with SigO.

σ factors are single subunit general transcription factors that reversibly bind core RNA polymerase and mediate gene-specific transcription in bacteria. Previously, an atypical two-subunit σ factor was identified that activates transcription from a group of related promoters in Bacillus subtilis. Both of the subunits, named SigO and RsoA, share primary sequence similarity with the canonical σ70 family of σ factors and interact with each other and with RNA polymerase subunits. Here we show that the σ70 region 2.3-like segment of RsoA is unexpectedly sufficient for interaction with the amino-terminus of SigO and the ß' subunit. A mutational analysis of RsoA identified aromatic residues conserved amongst all RsoA homologues, and often amongst canonical σ factors, that are particularly important for the SigO-RsoA interaction. In a canonical σ factor, region 2.3 amino acids bind non-template strand DNA, trapping the promoter in a single-stranded state required for initiation of transcription. Accordingly, we speculate that RsoA region 2.3 protein-binding activity likely arose from a motif that, at least in its ancestral protein, participated in DNA-binding interactions.

The Incidence of Parkinson's Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: Parkinson's disease (PD) is a common neurodegenerative disorder. Epidemiological studies on the incidence of PD are important to better understand the risk factors for PD and determine the condition's natural history. OBJECTIVE: This systematic review and meta-analysis examine the incidence of PD and its variation by age and gender. METHODS: We searched MEDLINE and EMBASE for epidemiologic studies of PD from 2001 to 2014, as a previously published systematic review included studies published until 2001. Data were analyzed separately for age group and gender, and meta-regression was used to determine whether a significant difference was present between groups. RESULTS: Twenty-seven studies were included in the analysis. Meta-analysis of international studies showed rising incidence with age in both men and women. Significant heterogeneity was observed in the 80+ group, which may be explained by methodological differences between studies. While males had a higher incidence of PD in all age groups, this difference was only statistically significant for those in the age range 60-69 and 70-79 (p < 0.05). CONCLUSION: PD incidence generally increases with age, although it may stabilize in those who are 80+.

The Prevalence and Incidence of Dementia with Lewy Bodies: a Systematic Review.

BACKGROUND: Population-based prevalence and incidence studies are essential for understanding the societal burden of dementia with Lewy bodies (DLB). METHODS: The MEDLINE and EMBASE databases were searched to identify publications addressing the incidence and/or prevalence of DLB. References of included articles and prior systematic reviews were searched for additional studies. Two reviewers screened all abstracts and full-text reviews, abstracted data and performed quality assessments. RESULTS: Twenty-two studies were included. Incidence rates ranged from 0.5 to 1.6 per 1000 person-years. DLB accounted for 3.2-7.1% of all dementia cases in the incidence studies. Point and period prevalence estimates ranged from 0.02 to 63.5 per 1000 persons. Increasing prevalence estimates were reported with increasing age. DLB accounted for from 0.3 to 24.4% of all cases of dementia in the prevalence studies. CONCLUSIONS: DLB becomes more common with increasing age and accounts for about 5% of all dementia cases in older populations.

Prevalence of Surgical Site Infections Following Orthognathic Surgery: A Retrospective Cohort Analysis.

PURPOSE: The purpose of this retrospective study was to determine the prevalence of surgical site infection (SSI) after orthognathic surgery at the Department of Oral and Maxillofacial Surgery of Capital Health and Dalhousie University (Halifax, NS, Canada). PATIENTS AND METHODS: A retrospective chart review of all patients undergoing orthognathic surgery from October 2005 through April 2013 was performed. The outcome variable was SSI. The primary predictor variable was the antibiotic used for prophylaxis. The secondary predictor variables were patient demographics, such as age, gender, medical comorbidities, and smoking status; duration of surgery; wisdom teeth extractions; single-jaw or bimaxillary surgery; and type of surgery. Data also were gathered on the diagnosis of SSIs and the treatment to resolve these infections. RESULTS: In total, 2,521 patients underwent surgery, and 253 patients did not meet the inclusion criteria; therefore, the charts of 2,268 patients were reviewed (mean ± standard deviation, 26.9 ± 11.7 yr of age). Eight percent of patients developed an SSI. None of the patient demographics was associated with an increased risk for infection. Most initial infections (62%) and most recurrent infections (78%) occurred in the mandible. Twenty-six percent of patients who developed SSIs had recurrent infections after antibiotic treatment. SSIs necessitated hardware removal for 14% of patients. Adverse effects from the antibiotics were seen in 4.2% of patients. Infection was most frequently diagnosed 11 to 15 days postoperatively. The average length of surgery for patients who did not have an SSI was 136 minutes compared with an average of 157 minutes for patients who had an SSI (odds ratio = 1.0051; 95% confidence interval, 1.0026 to 1.0076; P < .001). Wisdom teeth were extracted in 49.6% of the 2,268 cases. The mean SSI prevalence for multiple jaw procedures (9.2%) was significantly higher than that for single surgical procedures (5.3%; P = .0013). Isolated Le Fort surgeries had a significantly lower prevalence of infection compared with the mean prevalence (3.9%; P = .02), whether they were single piece or segmented (3.5 and 4.3%, respectively; P = .98). The prevalence of infection was significantly lower in the cefazolin group (6.2%) compared with the penicillin (14.3%; P < .0001) and clindamycin (10.4%; P < .02) groups. CONCLUSIONS: The prophylactic use of first-generation cephalosporins, such as cefazolin, appears to be more effective than penicillin and clindamycin for preventing SSIs in orthognathic surgery. In addition, bimaxillary surgery, mandibular procedures, and duration of surgery might demand antibiotic prophylaxis that is more effective. The presence of third molars and patient demographics are not risk factors for SSIs. A prospective randomized controlled study is underway to investigate the findings of this study.

The prevalence of Parkinson's disease: a systematic review and meta-analysis.

Parkinson's Disease (PD) is a common neurodegenerative disorder. We sought to synthesize studies on the prevalence of PD to obtain an overall view of how the prevalence of this disease varies by age, by sex, and by geographic location. We searched MEDLINE and EMBASE for epidemiological studies of PD from 1985 to 2010. Data were analyzed by age group, geographic location, and sex. Geographic location was stratified by the following groups: 1) Asia, 2) Africa, 3) South America, and 4) Europe/North America/Australia. Meta-regression was used to determine whether a significant difference was present between groups. Forty-seven studies were included in the analysis. Meta-analysis of the worldwide data showed a rising prevalence of PD with age (all per 100,000): 41 in 40 to 49 years; 107 in 50 to 59 years; 173 in 55 to 64 years; 428 in 60 to 69 years; 425 in 65 to 74 years; 1087 in 70 to 79 years; and 1903 in older than age 80. A significant difference was seen in prevalence by geographic location only for individuals 70 to 79 years old, with a prevalence of 1,601 in individuals from North America, Europe, and Australia, compared with 646 in individuals from Asia (P < 0.05). A significant difference in prevalence by sex was found only for individuals 50 to 59 years old, with a prevalence of 41 in females and 134 in males (P < 0.05). PD prevalence increases steadily with age. Some differences in prevalence by geographic location and sex can be detected.

Causal Forest Machine Learning Analysis of Parkinson's Disease in Resting-State Functional Magnetic Resonance Imaging.

In recent years, Artificial Intelligence has been used to assist healthcare professionals in detecting and diagnosing neurodegenerative diseases. In this study, we propose a methodology to analyze functional Magnetic Resonance Imaging signals and perform classification between Parkinson's disease patients and healthy participants using Machine Learning algorithms. In addition, the proposed approach provides insights into the brain regions affected by the disease. The functional Magnetic Resonance Imaging from the PPMI and 1000-FCP datasets were pre-processed to extract time series from 200 brain regions per participant, resulting in 11,600 features. Causal Forest and Wrapper Feature Subset Selection algorithms were used for dimensionality reduction, resulting in a subset of features based on their heterogeneity and association with the disease. We utilized Logistic Regression and XGBoost algorithms to perform PD detection, achieving 97.6% accuracy, 97.5% F1 score, 97.9% precision, and 97.7%recall by analyzing sets with fewer than 300 features in a population including men and women. Finally, Multiple Correspondence Analysis was employed to visualize the relationships between brain regions and each group (women with Parkinson, female controls, men with Parkinson, male controls). Associations between the Unified Parkinson's Disease Rating Scale questionnaire results and affected brain regions in different groups were also obtained to show another use case of the methodology. This work proposes a methodology to (1) classify patients and controls with Machine Learning and Causal Forest algorithm and (2) visualize associations between brain regions and groups, providing high-accuracy classification and enhanced interpretability of the correlation between specific brain regions and the disease across different groups.

White matter hyperintensities and smaller cortical thickness are associated with neuropsychiatric symptoms in neurodegenerative and cerebrovascular diseases.

BACKGROUND: Neuropsychiatric symptoms (NPS) are a core feature of most neurodegenerative and cerebrovascular diseases. White matter hyperintensities and brain atrophy have been implicated in NPS. We aimed to investigate the relative contribution of white matter hyperintensities and cortical thickness to NPS in participants across neurodegenerative and cerebrovascular diseases. METHODS: Five hundred thirteen participants with one of these conditions, i.e. Alzheimer's Disease/Mild Cognitive Impairment, Amyotrophic Lateral Sclerosis, Frontotemporal Dementia, Parkinson's Disease, or Cerebrovascular Disease, were included in the study. NPS were assessed using the Neuropsychiatric Inventory - Questionnaire and grouped into hyperactivity, psychotic, affective, and apathy subsyndromes. White matter hyperintensities were quantified using a semi-automatic segmentation technique and FreeSurfer cortical thickness was used to measure regional grey matter loss. RESULTS: Although NPS were frequent across the five disease groups, participants with frontotemporal dementia had the highest frequency of hyperactivity, apathy, and affective subsyndromes compared to other groups, whilst psychotic subsyndrome was high in both frontotemporal dementia and Parkinson's disease. Results from univariate and multivariate results showed that various predictors were associated with neuropsychiatric subsyndromes, especially cortical thickness in the inferior frontal, cingulate, and insula regions, sex(female), global cognition, and basal ganglia-thalamus white matter hyperintensities. CONCLUSIONS: In participants with neurodegenerative and cerebrovascular diseases, our results suggest that smaller cortical thickness and white matter hyperintensity burden in several cortical-subcortical structures may contribute to the development of NPS. Further studies investigating the mechanisms that determine the progression of NPS in various neurodegenerative and cerebrovascular diseases are needed.

Cognitive correlates of antisaccade behaviour across multiple neurodegenerative diseases.

Oculomotor tasks generate a potential wealth of behavioural biomarkers for neurodegenerative diseases. Overlap between oculomotor and disease-impaired circuitry reveals the location and severity of disease processes via saccade parameters measured from eye movement tasks such as prosaccade and antisaccade. Existing studies typically examine few saccade parameters in single diseases, using multiple separate neuropsychological test scores to relate oculomotor behaviour to cognition; however, this approach produces inconsistent, ungeneralizable results and fails to consider the cognitive heterogeneity of these diseases. Comprehensive cognitive assessment and direct inter-disease comparison are crucial to accurately reveal potential saccade biomarkers. We remediate these issues by characterizing 12 behavioural parameters, selected to robustly describe saccade behaviour, derived from an interleaved prosaccade and antisaccade task in a large cross-sectional data set comprising five disease cohorts (Alzheimer's disease/mild cognitive impairment, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson's disease, and cerebrovascular disease; n = 391, age 40-87) and healthy controls (n = 149, age 42-87). These participants additionally completed an extensive neuropsychological test battery. We further subdivided each cohort by diagnostic subgroup (for Alzheimer's disease/mild cognitive impairment and frontotemporal dementia) or degree of cognitive impairment based on neuropsychological testing (all other cohorts). We sought to understand links between oculomotor parameters, their relationships to robust cognitive measures, and their alterations in disease. We performed a factor analysis evaluating interrelationships among the 12 oculomotor parameters and examined correlations of the four resultant factors to five neuropsychology-based cognitive domain scores. We then compared behaviour between the abovementioned disease subgroups and controls at the individual parameter level. We theorized that each underlying factor measured the integrity of a distinct task-relevant brain process. Notably, Factor 3 (voluntary saccade generation) and Factor 1 (task disengagements) significantly correlated with attention/working memory and executive function scores. Factor 3 also correlated with memory and visuospatial function scores. Factor 2 (pre-emptive global inhibition) correlated only with attention/working memory scores, and Factor 4 (saccade metrics) correlated with no cognitive domain scores. Impairment on several mostly antisaccade-related individual parameters scaled with cognitive impairment across disease cohorts, while few subgroups differed from controls on prosaccade parameters. The interleaved prosaccade and antisaccade task detects cognitive impairment, and subsets of parameters likely index disparate underlying processes related to different cognitive domains. This suggests that the task represents a sensitive paradigm that can simultaneously evaluate a variety of clinically relevant cognitive constructs in neurodegenerative and cerebrovascular diseases and could be developed into a screening tool applicable to multiple diagnoses.

The prevalence of primary dystonia: a systematic review and meta-analysis.

Dystonia is a hyperkinetic movement disorder characterized by sustained muscle contractions that produce repetitive movements and abnormal postures. Specific information on the prevalence of dystonia has been difficult to establish because the existing epidemiological studies of the condition have adopted different methodologies for case ascertainment, resulting in widely differing reported prevalence. Medline and Embase databases were searched using terms specific to dystonia for studies of incidence, prevalence, and epidemiology. All population-based studies reporting an incidence and/or prevalence of primary dystonia were included. Sixteen original studies were included in our systematic review. Fifteen studies reported the prevalence of dystonia, including 12 service-based and three population-based studies. We performed a meta-analysis on the results of the service-based studies, and were able to combine data on the prevalence of several dystonia subtypes. From these studies, we calculated an overall prevalence of primary dystonia of 16.43 per 100,000 (95% confidence interval [CI]: 12.09-22.32). The prevalence of dystonia reported in the three population-based studies appears higher than that reported in the service-based studies. Only 1 of the 16 studies reported an incidence of cervical dystonia. This corresponded to a corrected incidence estimate of 1.07 per 100,000 person-years (95% CI: 0.86-1.32). Despite numerous studies on the epidemiology of dystonia, attempting to determine an accurate prevalence of the condition for health services planning remains a significant challenge. Given the methodological limitations of the existing studies, our own prevalence estimate of primary dystonia likely underestimates the true prevalence of the condition.

The incidence and prevalence of Huntington's disease: a systematic review and meta-analysis.

Huntington's disease (HD) is a rare, neurodegenerative disorder characterized by chorea, behavioral manifestations, and dementia. The aim of this study was to estimate the incidence and prevalence of HD through a systematic review of the literature. Medline and Embase databases were searched using terms specific to HD as well as studies of incidence, prevalence, and epidemiology. All studies reporting the incidence and/or prevalence of HD were included. Twenty original research articles were included. Eight studies examined incidence, and 17 studies examined prevalence. Meta-analysis of data from four incidence studies revealed an incidence of 0.38 per 100,000 per year (95% confidence interval [CI]: 0.16, 0.94). Lower incidence was reported in the Asian studies (n = 2), compared to the studies performed in Europe, North America, and Australia (n = 6). The worldwide service-based prevalence of HD, based on a meta-analysis (n = 13 studies), was 2.71 per 100,000 (95% CI: 1.55-4.72). Eleven studies were conducted in Europe, North American, and Australia, with an overall prevalence of 5.70 per 100,000 (95% CI: 4.42-7.35). Three studies were conducted in Asia, with an overall prevalence of 0.40 per 100,000 (95% CI: 0.26-0.61). Metaregression revealed a significantly lower prevalence of HD in Asia, compared to European, North American, and Australian populations. HD is a devastating neurodegenerative disorder with a higher prevalence in Europe, North America, and Australia than in Asia. The difference in prevalence of this genetic disorder can be largely explained by huntingtin gene haplotypes.

Canadian guidelines for the evidence-based treatment of tic disorders: behavioural therapy, deep brain stimulation, and transcranial magnetic stimulation.

This clinical guideline provides recommendations for nonpharmacological treatments for tic disorders. We conducted a systematic literature search for clinical trials on the treatment of tics. One evidence-based review (including 30 studies) and 3 studies on behavioural interventions, 3 studies on deep brain stimulation (DBS), and 3 studies on transcranial magnetic stimulation (TMS) met our inclusion criteria. Based on this evidence, we have made strong recommendations for the use of habit reversal therapy and exposure and response prevention, preferably embedded within a supportive, psychoeducational program, and with the option to combine either of these approaches with pharmacotherapy. Although evidence exists for the efficacy of DBS, the quality of this evidence is poor and the risks and burdens of the procedure are finely balanced with the perceived benefits. Our recommendation is that this intervention continues to be considered an experimental treatment for severe, medically refractory tics that have imposed severe limitations on quality of life. We recommend that the procedure should only be performed within the context of research studies and by physicians expert in DBS programming and in the management of tics. There is no evidence to support the use of TMS in the treatment of tics. However, the procedure is associated with a low rate of known complications and could continue to be evaluated within research protocols. The recommendations we provide are based on current knowledge, and further studies may result in their revision in future.

Canadian guidelines for the evidence-based treatment of tic disorders: pharmacotherapy.

This article seeks to provide the practising clinician with guidance on the pharmacological management of tic disorders in children and adults. We performed a systematic review of the literature on the treatment of tic disorders. A multi-institutional group of 14 experts in psychiatry, child psychiatry, neurology, pediatrics, and psychology engaged in a consensus meeting. The evidence was presented and discussed, and nominal group techniques were employed to arrive at consensus on recommendations. A strong recommendation is made when the benefits of treatment clearly outweigh the risks and burdens, and can apply to most patients in most circumstances without reservation. With a weak recommendation, the benefits, risks, and burdens are more closely balanced, and the best action may differ depending on the circumstances. Based on these principles, weak recommendations were made for the use of pimozide, haloperidol, fluphenazine, metoclopramide (children only), risperidone, aripiprazole, olanzapine, quetiapine, ziprasidone, topiramate, baclofen (children only), botulinum toxin injections, tetrabenazine, and cannabinoids (adults only). Strong recommendations were made for the use of clonidine and guanfacine (children only). While the evidence supports the efficacy of many of the antipsychotics for the treatment of tics, the high rates of side effects associated with these medications resulted in only weak recommendations for these drugs. In situations where tics are not severe or disabling, the use of a medication with only a weak recommendation is not warranted. However, when tics are more distressing and interfering, the need for tic suppression to improve quality of life is stronger, and patients and clinicians may be more willing to accept the risks of pharmacotherapy.

Targeted copy number variant identification across the neurodegenerative disease spectrum.

BACKGROUND: Although genetic factors are known to contribute to neurodegenerative disease susceptibility, there remains a large amount of heritability unaccounted for across the diagnoses. Copy number variants (CNVs) contribute to these phenotypes, but their presence and influence on disease state remains relatively understudied. METHODS: Here, we applied a depth of coverage approach to detect CNVs in 80 genes previously associated with neurodegenerative disease within participants of the Ontario Neurodegenerative Disease Research Initiative (n = 519). RESULTS: In total, we identified and validated four CNVs in the cohort, including: (1) a heterozygous deletion of exon 5 in OPTN in an Alzheimer's disease participant; (2) a duplication of exons 1-5 in PARK7 in an amyotrophic lateral sclerosis participant; (3) a duplication of >3 Mb, which encompassed ABCC6, in a cerebrovascular disease (CVD) participant; and (4) a duplication of exons 7-11 in SAMHD1 in a mild cognitive impairment participant. We also identified 43 additional CNVs that may be candidates for future replication studies. CONCLUSION: The identification of the CNVs suggests a portion of the apparent missing heritability of the phenotypes may be due to these structural variants, and their assessment is imperative for a thorough understanding of the genetic spectrum of neurodegeneration.

Investigating the contribution of white matter hyperintensities and cortical thickness to empathy in neurodegenerative and cerebrovascular diseases.

Change in empathy is an increasingly recognised symptom of neurodegenerative diseases and contributes to caregiver burden and patient distress. Empathy impairment has been associated with brain atrophy but its relationship to white matter hyperintensities (WMH) is unknown. We aimed to investigate the relationships amongst WMH, brain atrophy, and empathy deficits in neurodegenerative and cerebrovascular diseases. Five hundred thirteen participants with Alzheimer's disease/mild cognitive impairment, amyotrophic lateral sclerosis, frontotemporal dementia (FTD), Parkinson's disease, or cerebrovascular disease (CVD) were included. Empathy was assessed using the Interpersonal Reactivity Index. WMH were measured using a semi-automatic segmentation and FreeSurfer was used to measure cortical thickness. A heterogeneous pattern of cortical thinning was found between groups, with FTD showing thinning in frontotemporal regions and CVD in left superior parietal, left insula, and left postcentral. Results from both univariate and multivariate analyses revealed that several variables were associated with empathy, particularly cortical thickness in the fronto-insulo-temporal and cingulate regions, sex (female), global cognition, and right parietal and occipital WMH. Our results suggest that cortical atrophy and WMH may be associated with empathy deficits in neurodegenerative and cerebrovascular diseases. Future work should consider investigating the longitudinal effects of WMH and atrophy on empathy deficits in neurodegenerative and cerebrovascular diseases.