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Cognitive impairment is the most frequent non-motor symptom in Parkinson's disease and is associated with deficits in a number of cognitive functions including working memory. However, the pathophysiology of Parkinson's disease cognitive impairment is poorly understood. Beta oscillations have previously been shown to play an important role in cognitive functions including working memory encoding. Decreased dopamine in motor cortico-striato-thalamo-cortical (CSTC) circuits increases the spectral power of beta oscillations and results in Parkinson's disease motor symptoms. Analogous changes in parallel cognitive CSTC circuits involving the caudate and dorsolateral prefrontal cortex (DLPFC) may contribute to Parkinson's disease cognitive impairment. The objective of our study is to evaluate whether changes in beta oscillations in the caudate and DLPFC contribute to cognitive impairment in Parkinson's disease patients. To investigate this, we used local field potential recordings during deep brain stimulation surgery in 15 patients with Parkinson's disease. Local field potentials were recorded from DLPFC and caudate at rest and during a working memory task. We examined changes in beta oscillatory power during the working memory task as well as the relationship of beta oscillatory activity to preoperative cognitive status, as determined from neuropsychological testing results. We additionally conducted exploratory analyses on the relationship between cognitive impairment and task-based changes in spectral power in additional frequency bands. Spectral power of beta oscillations decreased in both DLPFC and caudate during working memory encoding and increased in these structures during feedback. Subjects with cognitive impairment had smaller decreases in caudate and DLPFC beta oscillatory power during encoding. In our exploratory analysis, we found that similar differences occurred in alpha frequencies in caudate and theta and alpha in DLPFC. Our findings suggest that oscillatory power changes in cognitive CSTC circuits may contribute to cognitive symptoms in patients with Parkinson's disease. These findings may inform the future development of novel neuromodulatory treatments for cognitive impairment in Parkinson's disease. [ABSTRACT FROM AUTHOR]

Background: Essential tremor (ET) patients present with both motor and non-motor symptoms including depression. Although deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) is used to treat motor symptoms of ET, there is no consensus as to how VIM DBS influences non-motor symptoms, specifically depression. Objective: The objective of this study was to conduct a meta-analysis of available studies investigating change in pre- to postoperative depression scores as measured by Beck Depression Inventory (BDI) in ET patients receiving VIM DBS. Methods: Inclusion criteria were randomized control trials or observational studies of patients undergoing unilateral/bilateral VIM DBS. Non-ET patients, case reports, patients <18 years old, only non-VIM electrode placement, non-English articles, and abstracts were excluded. The primary outcome was change in BDI score from the preoperative time point to the last available follow-up. Pooled estimates of overall effect for BDI standardized mean difference were calculated using random effects models with the inverse variance method. Results: Seven studies divided into eight cohorts for a total of 281 ET patients met inclusion criteria. Pooled preoperative BDI score was 12.44 (95% CI [6.63–18.25]). A statistically significant decrease in depression scores was observed postoperatively (SMD = −0.29, 95% CI [−0.46 to −0.13], p = 0.0006). Pooled postoperative BDI score was 9.18 (95% CI [4.98–13.38]). A supplementary analysis which included an additional study with an estimated standard deviation at last follow-up was conducted. There was also a statistically significant decrease in depression postoperatively (9 cohorts, n = 352, SMD = −0.31, 95% CI [−0.46 to −0.16], p < 0.0001). Conclusions: Both quantitative and qualitative analyses of the existing literature suggest that VIM DBS improves depression postoperatively among ET patients. These results may guide surgical risk-benefit analysis and counseling for ET patients undergoing VIM DBS. [ABSTRACT FROM AUTHOR]

Objective: Ventriculoperitoneal (VP) shunting is commonly used to treat normal pressure hydrocephalus (NPH). Assessment of cognition and balance pre- and post-lumbar drain (LD) can be used to provide objective metrics which may help determine the potential benefit of VP shunting. The aim of this investigation was to determine which measures identify clinical change as a result of a LD trial and to develop recommendations for standard NPH clinical assessment procedures. Methods: The Berg Balance Scale (BBS) and a brief battery of commonly used neuropsychological tests pre- and post-LD (MMSE, trail making test, animal fluency, Hopkins Verbal Learning Test – Revised, and digit span) were administered to 86 patients with a diagnosis of NPH. Subjects were divided into groups based on whether or not clinical change was present, and thus, VP shunting was recommended post-LD, and predictors of group membership were examined. Results: Significant improvements (p < 0.05) were seen on the BBS and Trail Making Part B in the VP shunt-recommended group, with no other significant changes over time in either group. Regression analyses found that VP shunt recommendation was accurately predicted for 80% of the sample using the BBS score alone, with accuracy increasing to 85% when Trails B was added. Conclusions: Scores from the BBS and Trails B were most likely to change in those chosen to undergo VP shunting post-LD. Given that the typical clinical presentation of NPH includes gait disturbance and cognitive impairment, it is recommended that a standard pre-/post-LD evaluation include the BBS and trail making test. [ABSTRACT FROM AUTHOR]

Objective: Performance validity tests (PVTs) are designed to detect nonvalid responding on neuropsychological testing, but their associations with disease-specific and other factors are not well understood in multiple sclerosis (MS). We examined PVT performance among MS patients and associations with clinical characteristics, cognition, mood, and disability status. Method: Retrospective data analysis was conducted on a sample of patients with definite MS (n = 102) who were seen for a clinical neuropsychological evaluation. Comparison samples included patients with intractable epilepsy seen for presurgical workup (n = 102) and patients with nonacute mild traumatic brain injury (mTBI; n = 50). Patients completed the Victoria Symptom Validity Test (VSVT) and validity cutoffs were defined as <16/24 and <18/24 on the hard items. Results: In this MS cohort, 14.4% of patients scored <16 on the VSVT hard items and 21.2% scored <18. VSVT hard item scores were associated with disability status and depression, but not with neuropsychological scores, T2 lesion burden, atrophy, disease duration, or MS subtype. Patients applying for disability benefits were 6.75 times more likely to score <18 relative to those who were not seeking disability. Rates of nonvalid scores were similar to the mTBI group and greater than the epilepsy group. Conclusions: This study demonstrates that nonvalid VSVT scores are relatively common among MS patients seen for clinical neuropsychological evaluation. VSVT performance in this group relates primarily to disability status and psychological symptoms and does not reflect factors specific to MS (i.e., cognitive impairment, disease severity). Recommendations for future clinical and research practices are provided. [ABSTRACT FROM AUTHOR]

Objective The feasibility and reliability of neuropsychological assessment at a distance have been demonstrated, but the validity of this testing medium has not been adequately demonstrated. The purpose of this study was to determine the ability of video teleconferencing administration of neuropsychological measures (teleneuropsychology) in discriminating cognitively impaired from non-impaired groups of older adults. It was predicted that measures administered via video teleconference would distinguish groups and that the magnitude of differences between impaired and non-impaired groups would be similar to group differences achieved in traditional administration. Methods The sample consisted of 197 older subjects, separated into two groups, with and without cognitive impairment. The cognitive impairment group included 78 individuals with clinical diagnoses of mild cognitive impairment or Alzheimer's disease. All participants completed counterbalanced neuropsychological testing using alternate test forms in both a teleneuropsychology and a traditional face-to-face (FTF) administration condition. Tests were selected based upon their common use in dementia evaluations, brevity, and assessment of multiple cognitive domains. Results from FTF and teleneuropsychology test conditions were compared using individual repeated measures ANCOVA, controlling for age, education, gender, and depression scores. Results All ANCOVA models revealed significant main effects of group and a non-significant interaction between group and administration condition. All ANCOVA models revealed non-significant main effects for administration condition, except category fluency. Conclusions Results derived from teleneuropsychologically administered tests can distinguish between cognitively impaired and non-impaired individuals similar to traditional FTF assessment. This adds to the growing teleneuropsychology literature by supporting the validity of remote assessments in aging populations. [ABSTRACT FROM AUTHOR]

There are no cures for neurodegenerative diseases and this is partially due to the difficulty of monitoring pathogenic molecules in patients during life. The Parkinson's disease gene α-synuclein (SNCA) is selectively expressed in blood cells and neurons. Here we show that SNCA transcripts in circulating blood cells are paradoxically reduced in early stage, untreated and dopamine transporter neuroimaging-supported Parkinson's disease in three independent regional, national, and international populations representing 500 cases and 363 controls and on three analogue and digital platforms with P < 0.0001 in meta-analysis. Individuals with SNCA transcripts in the lowest quartile of counts had an odds ratio for Parkinson's disease of 2.45 compared to individuals in the highest quartile. Disease-relevant transcript isoforms were low even near disease onset. Importantly, low SNCA transcript abundance predicted cognitive decline in patients with Parkinson's disease during up to 5 years of longitudinal follow-up. This study reveals a consistent association of reduced SNCA transcripts in accessible peripheral blood and early-stage Parkinson's disease in 863 participants and suggests a clinical role as potential predictor of cognitive decline. Moreover, the three independent biobank cohorts provide a generally useful platform for rapidly validating any biological marker of this common disease. [ABSTRACT FROM AUTHOR]