Belden, Christine M.

AbstractIntroductionRapid eye movement (REM) sleep behavior disorder (RBD) in Parkinson's disease (PD) is associated with differences in clinical phenotype, including dementia, autonomic loss, and gait dysfunction. The pathological basis for this remains unclear.MethodsParkinson's disease subjects in a longitudinal clinicopathologic study were screened for probable RBD with the Mayo Sleep Questionnaire. After death, semiquantitative analyses were conducted for synuclein, amyloid, neurofibrillary tangles, and cerebrovascular lesions.ResultsForty cases had probable RBD (PD+RBD), and 41 did not (PD‐RBD). Despite similar age at death (∼80 y) and disease duration (∼14.5 y), PD+RBD had increased synuclein deposition in all regions examined, with nine of 10 regions significantly different. The Lewy body 10‐region total score (scale = 0‐40) was 29.5 in PD+RBD versus 24.5 in PD‐RBD (Cohen‐d effect size = 0.79, P = 0.002). Cerebrovascular lesion burden was slightly higher in PD‐RBD.ConclusionsAlthough overlap occurs between groups, PD patients with probable RBD may have greater density and range of synuclein pathology on autopsy. © 2015 International Parkinson and Movement Disorder Society

Abstract Background Hyposmia is common in Parkinson's disease (PD) and is also observed with normal aging. It can be ascertained through objective testing, but it is unclear whether patients are aware of deficits and whether this has implications for cognitive status. Methods Subjects in the Arizona Study of Aging and Neurodegenerative Disorders were studied with annual motor and cognitive testing with objective smell testing (University of Pennsylvania Smell Identification Test; UPSIT ) done every third year beginning in 2002. Those with a baseline UPSIT <25th percentile (hyposmia) were studied for presence of unawareness of hyposmia and cognitive status. Results There were 75 subjects with PD and 143 nonparkinsonian controls with hyposmia. Lack of awareness of hyposmia was present in 16% of PD subjects and 47% of those without PD . In PD , there was no increase in unawareness in PD with dementia. In non‐ PD controls, unawareness was correlated with presence of dementia. Unawareness of hyposmia correlated most strongly with the neuropsychiatric tests of learning and memory. In controls without dementia or PD , 48% were unaware. Conclusions Querying patients about anosmia might be useful in parkinsonian disorders without objective testing. However, in elderly controls, it should be followed by objective testing and lack of awareness has implications for worsened cognitive status.

The Brain and Body Donation Program (BBDP) at Banner Sun Health Research Institute (http://www.brainandbodydonationprogram.org) started in 1987 with brain‐only donations and currently has banked more than 1600 brains. More than 430 whole‐body donations have been received since this service was commenced in 2005. The collective academic output of the BBDP is now described as the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND). Most BBDP subjects are enrolled as cognitively normal volunteers residing in the retirement communities of metropolitan Phoenix, Arizona. Specific recruitment efforts are also directed at subjects with Alzheimer's disease, Parkinson's disease and cancer. The median age at death is 82. Subjects receive standardized general medical, neurological, neuropsychological and movement disorders assessments during life and more than 90% receive full pathological examinations by medically licensed pathologists after death. The Program has been funded through a combination of internal, federal and state of Arizona grants as well as user fees and pharmaceutical industry collaborations. Subsets of the Program are utilized by the US National Institute on Aging Arizona Alzheimer's Disease Core Center and the US National Institute of Neurological Disorders and Stroke National Brain and Tissue Resource for Parkinson's Disease and Related Disorders. Substantial funding has also been received from the Michael J. Fox Foundation for Parkinson's Research. The Program has made rapid autopsy a priority, with a 3.0‐hour median post‐mortem interval for the entire collection. The median RNA Integrity Number (RIN) for frozen brain and body tissue is 8.9 and 7.4, respectively. More than 2500 tissue requests have been served and currently about 200 are served annually. These requests have been made by more than 400 investigators located in 32 US states and 15 countries. Tissue from the BBDP has contributed to more than 350 publications and more than 200 grant‐funded projects.

The objective is to examine the risk of dementia in subjects with essential tremor (ET) involved in the Arizona Study of Aging and Neurodegenerative Disorders. All subjects were free of a neurodegenerative diagnosis at baseline and had annual motor, general neurological, and neuropsychological assessments. Subjects with ET were compared with controls for the risk of dementia. There were 83 subjects with ET and 424 subjects without tremor. Mean age at study entry was 80±5.9 for ET and 76±8.5 for controls. Median tremor duration was 5.2 years at study entry. Followup was a median of 5.4 years (range 0.9 to 12.1). The hazard ratio for the association between ET and dementia was 0.79 (95% CI 0.33 to 1.85). The hazard ratio for the association between tremor onset at age 65 or over, versus onset before age 65, was 2.1 (95% CI 0.24 to 18) and the hazard ratio for the association between tremor duration greater than 5 years, versus less than 5 years, was 0.46 (95% CI 0.08 to 2.6). We conclude that all elderly ET was not associated with an increased risk of dementia but that a subset of subjects with older age onset/shorter duration tremor may be at higher risk.

Aberrant connectivity is implicated in many neurological and psychiatric disorders, including Alzheimer’s disease and schizophrenia. However, other than a few disease-associated candidate genes, we know little about the degree to which genetics play a role in the brain networks; we know even less about specific genes that influence brain connections. Twin and family-based studies can generate estimates of overall genetic influences on a trait, but genome-wide association scans (GWASs) can screen the genome for specific variants influencing the brain or risk for disease. To identify the heritability of various brain connections, we scanned healthy young adult twins with high-field, high-angular resolution diffusion MRI. We adapted GWASs to screen the brain’s connectivity pattern, allowing us to discover genetic variants that affect the human brain’s wiring. The association of connectivity with the SPON1 variant at rs2618516 on chromosome 11 (11p15.2) reached connectome-wide, genome-wide significance after stringent statistical corrections were enforced, and it was replicated in an independent subsample. rs2618516 was shown to affect brain structure in an elderly population with varying degrees of dementia. Older people who carried the connectivity variant had significantly milder clinical dementia scores and lower risk of Alzheimer’s disease. As a posthoc analysis, we conducted GWASs on several organizational and topological network measures derived from the matrices to discover variants in and around genes associated with autism ( MACROD2 ), development ( NEDD4 ), and mental retardation ( UBE2A ) significantly associated with connectivity. Connectome-wide, genome-wide screening offers substantial promise to discover genes affecting brain connectivity and risk for brain diseases.