Sex differences in Parkinson disease-associated episodic memory and processing speed deficits.

OBJECTIVES: This study aims to address a gap in the data on cognitive sex differences in persons living with Parkinson disease (PD). There is some evidence that cognitive dysfunction is more severe in male PD, however data on episodic memory and processing speed is incomplete. METHODS: One hundred and sixty-seven individuals with a diagnosis of PD were included in this study. Fifty-six of those individuals identified as female. The California Verbal Learning Test 1st edition and the Wechsler Memory Scale 3rd edition were used to evaluate verbal and visuospatial episodic memory and the Wechsler Adult Intelligence Scale 3rd edition was used to evaluate processing speed. Multivariate analysis of covariance was used to identify sex-specific differences across groups. RESULTS: Our results show that males with PD performed significantly worse than females in verbal and visuospatial recall as well as a trend for the processing speed task of coding. CONCLUSIONS: Our finding of superior performance among females with PD in verbal episodic memory is consistent with reports in both healthy and PD individuals; however, females outperforming males in measures of visuospatial episodic memory is unique to PD. Cognitive deficits preferentially affecting males appear to be associated with frontal lobe-related function. Therefore, males may represent a disease subgroup more susceptible to disease mechanisms affecting frontal lobe deterioration and cognitive disturbances in PD.

Translating cell therapies for neurodegenerative diseases: Huntington's disease as a model disorder.

There has been substantial progress in the development of regenerative medicine strategies for CNS disorders over the last decade, with progression to early clinical studies for some conditions. However, there are multiple challenges along the translational pipeline, many of which are common across diseases and pertinent to multiple donor cell types. These include defining the point at which the preclinical data are sufficiently compelling to permit progression to the first clinical studies; scaling-up, characterization, quality control and validation of the cell product; design, validation and approval of the surgical device; and operative procedures for safe and effective delivery of cell product to the brain. Furthermore, clinical trials that incorporate principles of efficient design and disease-specific outcomes are urgently needed (particularly for those undertaken in rare diseases, where relatively small cohorts are an additional limiting factor), and all processes must be adaptable in a dynamic regulatory environment. Here we set out the challenges associated with the clinical translation of cell therapy, using Huntington's disease as a specific example, and suggest potential strategies to address these challenges. Huntington's disease presents a clear unmet need, but, importantly, it is an autosomal dominant condition with a readily available gene test, full genetic penetrance and a wide range of associated animal models, which together mean that it is a powerful condition in which to develop principles and test experimental therapeutics. We propose that solving these challenges in Huntington's disease would provide a road map for many other neurological conditions. This white paper represents a consensus opinion emerging from a series of meetings of the international translational platforms Stem Cells for Huntington's Disease and the European Huntington's Disease Network Advanced Therapies Working Group, established to identify the challenges of cell therapy, share experience, develop guidance and highlight future directions, with the aim to expedite progress towards therapies for clinical benefit in Huntington's disease.

Subdural Hematoma as a Serious Complication of Huntington's Disease: An Observational Study.

BACKGROUND: Persons with Huntington's disease (HD) are at increased risk for subdural hematomas (SDH) because of underlying brain atrophy and increased frequency of falls and head trauma. SDH can cause serious disability, but there is little information about the association of SDH with HD in the medical literature. OBJECTIVE: To review the occurrence and characteristics of SDH seen in clinics specializing in HD. METHODS: A retrospective review identifying the occurrence and manifestations of SDH in HD patients attending three HDSA Centers of Excellence. RESULTS: Twenty-five HD patients (16F/9M) were identified with SDH. Twelve (44%) SDH were bilateral, 16 (60%) required surgical intervention, and 2 resulted in death. Mean age at the time of SDH was 60 years, mean duration of HD symptoms prior to event was 8 years, mean CAG repeat expansion size was 43 and mean UHDRS motor score obtained closest to time of SDH was 51 (16 patients). Most SDH occurred in the context of ground level falls or using stairs although 5 patients had no history of head trauma. Additional brain injury may occur along with the SDH. The most common symptoms were altered mental status, hemiparesis and loss of consciousness. The over-representation of females in this study requires replication and further investigation. CONCLUSION: Patients with HD are at increased risk for SDH. An increased suspicion for SDH in HD patients should be considered, as this phenomenon may be initially unrecognized, may require extensive utilization of medical resources and is a potential cause of death.

Genotyping single nucleotide polymorphisms for allele-selective therapy in Huntington disease.

BACKGROUND: The huntingtin gene (HTT) pathogenic cytosine-adenine-guanine (CAG) repeat expansion responsible for Huntington disease (HD) is phased with single nucleotide polymorphisms (SNPs), providing targets for allele-selective treatments. OBJECTIVE: This prospective observational study defined the frequency at which rs362307 (SNP1) or rs362331 (SNP2) was found on the same allele with pathogenic CAG expansions. METHODS: Across 7 US sites, 202 individuals with HD provided blood samples that were processed centrally to determine the number and size of CAG repeats, presence and heterozygosity of SNPs, and whether SNPs were present on the mutant HTT allele using long-read sequencing and phasing. RESULTS: Heterozygosity of SNP1 and/or SNP2 was identified in 146 (72%) individuals. The 2 polymorphisms were associated only with the mHTT allele in 61% (95% high density interval: 55%, 67%) of individuals. CONCLUSIONS: These results are consistent with previous reports and demonstrate the feasibility of genotyping, phasing, and targeting of HTT SNPs for personalized treatment of HD.

Atypical antipsychotic therapy in Parkinson's disease psychosis: A retrospective study.

OBJECTIVE: Parkinson's disease psychosis (PDP) is a frequent complication of idiopathic Parkinson's disease (iPD) with significant impact on quality of life and association with poorer outcomes. Atypical antipsychotic drugs (APDs) are often used for the treatment of PDP; however, their use is often complicated by adverse drug reactions (ADRs). In this study, we present patients with PDP who were treated with the most commonly used atypical antipsychotic agents and review their respective ADRs. METHODS: A retrospective study was carried out to include a total of 45 patients with iPD who visited a movement disorders clinic between 2006 and 2015. All PDP patients treated with atypical APDs were included in the analysis for their specific ADRs. RESULTS: Forty-five iPD patients (mean age of onset: 62.67 ± 9.86 years) were included, of those 10 patients had psychosis (mean age of onset: 76.80 ± 4.61 years). Of the 45 patients, 22.2% were found to have psychotic symptoms, of whom 70% had hallucinations, 20% had delusions, and 10% illusions. Seventy percent of psychotic symptoms occurred after ten or more years from diagnosis of iPD. PDP patients were treated with quetiapine, olanzapine, and risperidone separately or in combination, all of which were found to have certain ADRs. LIMITATIONS: This study was limited by its retrospective study design and small sample size and with likely selection bias. CONCLUSIONS: The prevalence of PDP is relatively high in older patients with iPD. The uses of the currently available atypical APDs in this patient population are often complicated by ADRs. The selective 5-HT 2A inverse agonist, pimavanserin, could be a better alternative in the treatment of PDP.

A randomized, double-blind, placebo-controlled trial of coenzyme Q10 in Huntington disease.

OBJECTIVE: To test the hypothesis that chronic treatment of early-stage Huntington disease (HD) with high-dose coenzyme Q10 (CoQ) will slow the progressive functional decline of HD. METHODS: We performed a multicenter randomized, double-blind, placebo-controlled trial. Patients with early-stage HD (n = 609) were enrolled at 48 sites in the United States, Canada, and Australia from 2008 to 2012. Patients were randomized to receive either CoQ 2,400 mg/d or matching placebo, then followed for 60 months. The primary outcome variable was the change from baseline to month 60 in Total Functional Capacity score (for patients who survived) combined with time to death (for patients who died) analyzed using a joint-rank analysis approach. RESULTS: An interim analysis for futility revealed a conditional power of <5% for the primary analysis, prompting premature conclusion in July 2014. No statistically significant differences were seen between treatment groups for the primary or secondary outcome measures. CoQ was generally safe and well-tolerated throughout the study. CONCLUSIONS: These data do not justify use of CoQ as a treatment to slow functional decline in HD. CLINICALTRIALSGOV IDENTIFIER: NCT00608881. CLASSIFICATION OF EVIDENCE: This article provides Class I evidence that CoQ does not slow the progressive functional decline of patients with HD.

Allele-Specific Reduction of the Mutant Huntingtin Allele Using Transcription Activator-Like Effectors in Human Huntington's Disease Fibroblasts.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by an abnormal expansion of CAG repeats. Although pathogenesis has been attributed to this polyglutamine expansion, the underlying mechanisms through which the huntingtin protein functions have yet to be elucidated. It has been suggested that postnatal reduction of mutant huntingtin through protein interference or conditional gene knockout could prove to be an effective therapy for patients suffering from HD. For allele-specific targeting, transcription activator-like effectors (TALE) were designed to target single-nucleotide polymorphisms (SNP) in the mutant allele and packaged into a vector backbone containing KRAB to promote transcriptional repression of the disease-associated allele. Additional TALEs were packaged into a vector backbone containing heterodimeric FokI and were designed to be used as nucleases (TALEN) to cause a CAG-collapse in the mutant allele. Human HD fibroblasts were treated with each TALE-SNP or TALEN. Allele-expression was measured using a SNP-genotyping assay and mutant protein aggregation was quantified with Western blots for anti-ubiquitin. The TALE-SNP and TALEN significantly reduced mutant allele expression (p < 0.05) when compared to control transfections while not affecting expression of the nondisease allele. This study demonstrates the potential of allele-specific gene modification using TALE proteins, and provides a foundation for targeted treatment for individuals suffering from Huntington's or other genetically linked diseases.

Human Mesenchymal Stem Cells Genetically Engineered to Overexpress Brain-derived Neurotrophic Factor Improve Outcomes in Huntington's Disease Mouse Models.

Huntington's disease (HD) is a fatal degenerative autosomal dominant neuropsychiatric disease that causes neuronal death and is characterized by progressive striatal and then widespread brain atrophy. Brain-derived neurotrophic factor (BDNF) is a lead candidate for the treatment of HD, as it has been shown to prevent cell death and to stimulate the growth and migration of new neurons in the brain in transgenic mouse models. BDNF levels are reduced in HD postmortem human brain. Previous studies have shown efficacy of mesenchymal stem/stromal cells (MSC)/BDNF using murine MSCs, and the present study used human MSCs to advance the therapeutic potential of the MSC/BDNF platform for clinical application. Double-blinded studies were performed to examine the effects of intrastriatally transplanted human MSC/BDNF on disease progression in two strains of immune-suppressed HD transgenic mice: YAC128 and R6/2. MSC/BDNF treatment decreased striatal atrophy in YAC128 mice. MSC/BDNF treatment also significantly reduced anxiety as measured in the open-field assay. Both MSC and MSC/BDNF treatments induced a significant increase in neurogenesis-like activity in R6/2 mice. MSC/BDNF treatment also increased the mean lifespan of the R6/2 mice. Our genetically modified MSC/BDNF cells set a precedent for stem cell-based neurotherapeutics and could potentially be modified for other neurodegenerative disorders such as amyotrophic lateral sclerosis, Alzheimer's disease, and some forms of Parkinson's disease. These cells provide a platform delivery system for future studies involving corrective gene-editing strategies.

Developing stem cell therapies for juvenile and adult-onset Huntington's disease.

Stem cell therapies have been explored as a new avenue for the treatment of neurologic disease and damage within the CNS in part due to their native ability to mimic repair mechanisms in the brain. Mesenchymal stem cells have been of particular clinical interest due to their ability to release beneficial neurotrophic factors and their ability to foster a neuroprotective microenviroment. While early stem cell transplantation therapies have been fraught with technical and political concerns as well as limited clinical benefits, mesenchymal stem cell therapies have been shown to be clinically beneficial and derivable from nonembryonic, adult sources. The focus of this review will be on emerging and extant stem cell therapies for juvenile and adult-onset Huntington's disease.

Subjective Cognitive Complaints in Parkinson Disease Without Dementia: A Preliminary Study.

Little is known about the subjective cognitive complaints of individuals with Parkinson disease (PD). Such complaints have become a topic of interest recently as they play a role in the diagnosis of neurocognitive disorders. The aim of this preliminary study was to determine whether a sample of nondemented individuals with PD reported significantly more difficulties with multiple elements of cognition than a control sample and to assess the relation between their ratings and demographics, motor symptom severity, neuropsychological test performance, and measures of depression and anxiety. Forty nondemented individuals with PD and 27 healthy individuals completed a questionnaire assessing everyday cognitive difficulties. Independent t tests indicated that individuals with PD reported significantly more cognitive complaints in general and in specific tasks involving complex attention, executive function, processing speed, and verbal fluency but not memory. Questionnaire ratings significantly correlated with measures assessing anxiety, verbal memory, processing speed, and verbal fluency. Results suggest that it is important to ask individuals with PD about cognitive complaints across several cognitive domains and also inquire about symptoms of anxiety, which may be related to their self-reported cognitive difficulties.

Treatment of γ-aminobutyric acid B receptor-antibody autoimmune encephalitis with oral corticosteroids.

BACKGROUND: Autoimmune encephalitis is increasingly identified as a cause of nonviral, idiopathic encephalitis. Present treatment algorithms recommend costly immune-modulating treatments and do not identify a role for oral corticosteroids. OBJECTIVE: To present a patient with γ-aminobutyric acid(B) receptor-antibody encephalitis before and after treatment with oral corticosteroids. DESIGN: Case report. SETTING: The inpatient course as well as outpatient follow-up is discussed. PATIENT: A 43-year-old man with initial presentation of seizures and altered mental status. INTERVENTION: Our patient was treated with an extended course of oral corticosteroids as an outpatient. RESULTS: After treatment with oral corticosteroids, our patient had steady clinical improvement, achieved seizure freedom, and experienced improved mental status to within normal limits. CONCLUSIONS: This case supports the use of low-cost oral corticosteroids in treating patients with γ-aminobutyric acid(B) receptor-antibody encephalitis.

Genetically engineered mesenchymal stem cells as a proposed therapeutic for Huntington's disease.

There is much interest in the use of mesenchymal stem cells/marrow stromal cells (MSC) to treat neurodegenerative disorders, in particular those that are fatal and difficult to treat, such as Huntington's disease. MSC present a promising tool for cell therapy and are currently being tested in FDA-approved phase I-III clinical trials for many disorders. In preclinical studies of neurodegenerative disorders, MSC have demonstrated efficacy, when used as delivery vehicles for neural growth factors. A number of investigators have examined the potential benefits of innate MSC-secreted trophic support and augmented growth factors to support injured neurons. These include overexpression of brain-derived neurotrophic factor and glial-derived neurotrophic factor, using genetically engineered MSC as a vehicle to deliver the cytokines directly into the microenvironment. Proposed regenerative approaches to neurological diseases using MSC include cell therapies in which cells are delivered via intracerebral or intrathecal injection. Upon transplantation, MSC in the brain promote endogenous neuronal growth, encourage synaptic connection from damaged neurons, decrease apoptosis, reduce levels of free radicals, and regulate inflammation. These abilities are primarily modulated through paracrine actions. Clinical trials for MSC injection into the central nervous system to treat amyotrophic lateral sclerosis, traumatic brain injury, and stroke are currently ongoing. The current data in support of applying MSC-based cellular therapies to the treatment of Huntington's disease is discussed.

Predictors of HVOT performance in Parkinson's disease.

Evidence suggests that the Hooper Visual Organization Test (HVOT) has naming and executive components that vary in size depending on neurological diagnosis. The current study used a sample of individuals with Parkinson's disease (PD) to demonstrate for the first time that an executive measure can be the best predictor of HVOT performance. Forty-eight nondemented and nondepressed individuals with idiopathic PD completed the HVOT and other measures of visuoperception, executive function, and visual confrontation naming. Despite average performance on all neuropsychological measures, an executive measure, time to complete Trail-Making Test Part B minus time to complete Part A, was clearly the best predictor of HVOT performance in a standard regression. The pattern of neurocognitive predictors is unlike that reported in healthy individuals and other patient samples. This finding suggests that the presence of a neuropathological process can alter neurocognitive correlates even when performance is intact, and supports the contention that executive function is paramount in the cognitive profile associated with PD.

Cerebral venous sinus thrombosis presenting with auditory hallucinations and illusions.

OBJECTIVE: Cerebral venous sinus thrombosis may present with seizures or neuropsychiatric symptoms, but does not typically present with hallucinations. We present a case of venous thrombosis of the right sigmoid and transverse sinuses that presented with auditory hallucinations and illusions. METHODS: We describe a 45-year-old woman with a history of myasthenia gravis, stable on oral prednisone and monthly intravenous immunoglobulin infusions, who started on a progesterone/estrogen combination contraceptive pill for menorrhagia 3 weeks before admission and presented with symptoms of headache, fever, and auditory hallucinations and illusions. RESULTS: The patient's cerebrospinal fluid showed lymphocytic pleocytosis. Two electroencephalograms showed significant right temporal lobe slowing. Magnetic resonance venogram of the brain showed venous sinus thrombosis of the right sigmoid and transverse sinuses. Magnetic resonance imaging showed a cortical venous infarct in the right middle temporal gyrus. The patient's auditory hallucinations and illusions resolved spontaneously weeks after presentation. CONCLUSIONS: This case suggests that auditory hallucinations and illusions should be added to the already broad spectrum of presenting features of cerebral venous sinus thrombosis. The nondominant right middle temporal gyrus may play a role in such auditory hallucinations.

The clinical significance of neuropsychological changes following bilateral subthalamic nucleus deep brain stimulation for Parkinson's disease.

Despite the clinical importance of the question, a number of methodological issues have limited firm conclusions regarding the cognitive safety of deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson's disease (PD). Amongst these issues, studies have generally failed to consider the postoperative changes that occur within individual patients. This study utilized reliable change indices (RCIs) derived from a PD sample to determine the frequency of clinically significant postoperative decline on a battery of neuropsychological measures. This approach addresses measurement reliability, potential practice effects, and disease progression. The proportion of patients experiencing clinically significant postoperative decline on measures of list learning and verbal fluency was greater than expected based on disease progression; however, the majority of patients (55%) did not experience a significant decline in performance on any of the cognitive tests administered, and only one experienced decline on more than one test. Therefore, the statistically significant declines on measures of list learning and verbal fluency observed in the sample as a whole were the result of clinically significant declines experienced by a minority of participants.

Cognitive deficits in essential tremor consistent with frontosubcortical dysfunction.

Essential tremor (ET) is increasingly thought to involve a heterogeneous group of patients, with some also exhibiting symptoms of Parkinson's disease (PD), including cognitive deficits. The goal of this study was to utilize a broad battery of neuropsychological measures to compare the cognitive function of 33 ET patients with that of 33 matched PD patients and 21 normal controls. Results indicated that the ET group performed significantly worse than controls across multiple cognitive domains, but performed remarkably similar to PD patients, consistent with frontosubcortical dysfunction.

Dopamine dependency of cognitive switching and response repetition effects in Parkinson's patients.

A group of people with Parkinson's disease and a group of matched controls were tested on a task involving a switch between perceptual dimensions. Patients were tested both 'on' and 'off' their normal medication cycles. Stimuli appeared in pairs for each trial, with each stimulus consisting of a color and a shape. One dimension of color and one of shape were mapped to each of two response keys. A cue was presented concurrently with each stimulus to indicate whether to respond on the basis of color or shape, following procedures developed by Hayes et al. [Hayes, A.E., Davidson, M.C., Keele, S.W., and Rafal, R.D. (1998). Toward a functional analysis of the basal ganglia. Journal of Cognitive Neuroscience, 10, 178-198]. Replicating previous literature, abnormally large switch costs were observed in patients who were off their normal medication cycles. A novel finding was that patients in the 'on' state demonstrated a slight reversal of switch costs. Also novel, reaction time (RT) costs associated with switching between response keys, and interactions between response switching and task switching were influenced predominantly by on-off dopamine manipulations. It is concluded that abnormal task switching costs and response repetition effects likely reflect impairments of activation and inhibition, and both effects are dopamine-dependent.