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1.  Association of the Neighborhood Retail Food Environment with Sodium and Potassium Intake Among US Adults 
High sodium intake and low potassium intake, which can contribute to hypertension and risk of cardiovascular disease, may be related to the availability of healthful food in neighborhood stores. Despite evidence linking food environment with diet quality, this relationship has not been evaluated in the United States. The modified retail food environment index (mRFEI) provides a composite measure of the retail food environment and represents the percentage of healthful-food vendors within a 0.5 mile buffer of a census tract.
We analyzed data from 8,779 participants in the National Health and Nutrition Examination Survey, 2005–2008. By using linear regression, we assessed the relationship between mRFEI and sodium intake, potassium intake, and the sodium–potassium ratio. Models were stratified by region (South and non-South) and included participant and neighborhood characteristics.
In the non-South region, higher mRFEI scores (indicating a more healthful food environment) were not associated with sodium intake, were positively associated with potassium intake (P [trend] = .005), and were negatively associated with the sodium–potassium ratio (P [trend] = .02); these associations diminished when neighborhood characteristics were included, but remained close to statistical significance for potassium intake (P [trend] = .05) and sodium–potassium ratio (P [trend] = .07). In the South, mRFEI scores were not associated with sodium intake, were negatively associated with potassium intake (P [trend] = < .001), and were positively associated with sodium–potassium ratio (P [trend] = .01). These associations also diminished after controlling for neighborhood characteristics for both potassium intake (P [trend] = .03) and sodium–potassium ratio (P [trend] = .40).
We found no association between mRFEI and sodium intake. The association between mRFEI and potassium intake and the sodium–potassium ratio varied by region. National strategies to reduce sodium in the food supply may be most effective to reduce sodium intake. Strategies aimed at the local level should consider regional context and neighborhood characteristics.
PMCID: PMC4008950  PMID: 24784906
2.  Nocturnal sleep enhances working memory training in Parkinson's disease but not Lewy body dementia 
Brain  2012;135(9):2789-2797.
Working memory is essential to higher order cognition (e.g. fluid intelligence) and to performance of daily activities. Though working memory capacity was traditionally thought to be inflexible, recent studies report that working memory capacity can be trained and that offline processes occurring during sleep may facilitate improvements in working memory performance. We utilized a 48-h in-laboratory protocol consisting of repeated digit span forward (short-term attention measure) and digit span backward (working memory measure) tests and overnight polysomnography to investigate the specific sleep-dependent processes that may facilitate working memory performance improvements in the synucleinopathies. We found that digit span backward performance improved following a nocturnal sleep interval in patients with Parkinson's disease on dopaminergic medication, but not in those not taking dopaminergic medication and not in patients with dementia with Lewy bodies. Furthermore, the improvements in patients with Parkinson's disease on dopaminergic medication were positively correlated with the amount of slow-wave sleep that patients obtained between training sessions and negatively correlated with severity of nocturnal oxygen desaturation. The translational implication is that working memory capacity is potentially modifiable in patients with Parkinson's disease but that sleep disturbances may first need to be corrected.
PMCID: PMC3577106  PMID: 22907117
consolidation; sleep; working memory; training; Parkinson's disease; dementia with Lewy bodies
3.  Daytime Alertness in Parkinson’s Disease: Potentially Dose-Dependent, Divergent Effects by Drug Class 
Many patients with idiopathic Parkinson’s disease experience difficulties maintaining daytime alertness. Controversy exists regarding whether this reflects effects of anti-Parkinsonian medications, the disease itself or other factors such as nocturnal sleep disturbances. In this study we examined the phenomenon by evaluating medicated and unmedicated Parkinson’s patients with objective polysomnographic measurements of nocturnal sleep and daytime alertness.
Patients (n = 63) underwent a 48-hour laboratory-based study incorporating 2 consecutive nights of overnight polysomnography and 2 days of Maintenance of Wakefulness Testing. We examined correlates of individual differences in alertness, including demographics, clinical features, nocturnal sleep variables and class and dosage of anti-Parkinson’s medications.
Results indicated that: 1) relative to unmediated patients, all classes of dopaminergic medications were associated with reduced daytime alertness and this effect was not mediated by disease duration or disease severity; 2) increasing dosages of dopamine agonists were associated with less daytime alertness, whereas higher levels of levodopa were associated with higher levels of alertness. Variables unrelated to Maintenance of Wakefulness Test defined daytime alertness included age, sex, years with diagnosis, motor impairment score and most nocturnal sleep variables.
Deficits in objectively assessed daytime alertness in Parkinson’s disease appear to be a function of both the disease and the medications and their doses utilized. The apparent divergent dose-dependent effects of drug class in Parkinson’s disease are anticipated by basic science studies of the sleep/wake cycle under different pharmacological agents.
PMCID: PMC3589103  PMID: 22753297
Parkinson’s Disease; Daytime Alertness; Sleep; Maintenance of Wakefulness Test; Dopaminergic Treatment
4.  Phasic Muscle Activity in Sleep and Clinical Features of Parkinson Disease 
Annals of neurology  2010;68(3):353-359.
The absence of atonia during rapid eye movement (REM) sleep and dream-enactment behavior (REM sleep behavior disorder [RBD]) are common features of sleep in the alpha-synucleinopathies. This study examined this phenomenon quantitatively, using the phasic electromyographic metric (PEM), in relation to clinical features of idiopathic Parkinson disease (PD). Based on previous studies suggesting that RBD may be prognostic for the development of later parkinsonism, we hypothesized that clinical indicators of disease severity and more rapid progression would be related to PEM.
A cross-sectional convenience sample of 55 idiopathic PD patients from a movement disorders clinic in a tertiary care medical center underwent overnight polysomnography. PEM, the percentage of 2.5-second intervals containing phasic muscle activity, was quantified separately for REM and non-REM (NREM) sleep from 5 different electrode sites.
Higher PEM rates were seen in patients with symmetric disease, as well as in akinetic-rigid versus tremor-predominant patients. Men had higher PEM relative to women. Results occurred in all muscle groups in both REM and NREM sleep.
Although our data were cross-sectional, phasic muscle activity during sleep suggests disinhibition of descending motor projections in PD broadly reflective of more advanced and/or progressive disease. Elevated PEM during sleep may represent a functional window into brainstem modulation of spinal cord activity and is broadly consistent with the early pathologic involvement of non-nigral brainstem regions in PD, as described by Braak.
PMCID: PMC3666956  PMID: 20626046
5.  Sleep Disturbance in Dementia with Lewy Bodies and Alzheimer's Disease: A Multicenter Analysis 
Evidence suggests that patients with dementia with Lewy bodies (DLB) may have more nocturnal sleep disturbance than patients with Alzheimer's disease (AD). We sought to confirm such observations using a large, prospectively collected, standardized, multicenter-derived database, i.e. the National Alzheimer's Coordinating Center Uniform Data Set.
Nocturnal sleep disturbance (NSD) data, as characterized by the Neuropsychiatric Inventory Questionnaire (NPI-Q), were derived from 4,531 patients collected between September 2005 and November 2008 from 32 National Institute on Aging participating AD centers. Patient and informant characteristics were compared between those with and without NSD by dementia diagnosis (DLB and probable AD). Finally, a logistic regression model was created to quantify the association between NSD status and diagnosis while adjusting for these patient/informant characteristics, as well as center.
NSD was more frequent in clinically diagnosed DLB relative to clinically diagnosed AD (odds ratio = 2.93, 95% confidence interval = 2.22–3.86). These results were independent from the gender of the patient or informant, whether the informant lived with the patient, and other patient characteristics, such as dementia severity, depressive symptoms, and NPI-Q-derived measures of hallucinations, delusions, agitation and apathy. In AD, but not DLB, patients, NSD was associated with more advanced disease. Comorbidity of NSD with hallucinations, agitation and apathy was higher in DLB than in AD. There was also evidence that the percentage of DLB cases with NSD showed wide variation across centers.
As defined by the NPI-Q, endorsement of the nocturnal behavior item by informants is more likely in patients with DLB when compared to AD, even after the adjustment of key patient/informant characteristics.
PMCID: PMC3085031  PMID: 21474933
Dementia with Lewy bodies; Alzheimer's disease; Sleep; Neuropsychiatric Inventory Questionnaire
6.  Geographic and Sociodemographic Disparities in Drive Times to Joint Commission–Certified Primary Stroke Centers in North Carolina, South Carolina, and Georgia 
Preventing Chronic Disease  2011;8(4):A79.
Timely access to facilities that provide acute stroke care is necessary to reduce disabilities and death from stroke. We examined geographic and sociodemographic disparities in drive times to Joint Commission–certified primary stroke centers (JCPSCs) and other hospitals with stroke care quality improvement initiatives in North Carolina, South Carolina, and Georgia.
We defined boundaries for 30- and 60-minute drive-time areas to JCPSCs and other hospitals  by  using geographic information systems (GIS) mapping technology and calculated the proportions of the population living in these drive-time areas by sociodemographic characteristics. Age-adjusted county-level stroke death rates were overlaid onto the drive-time areas.
Approximately 55% of the population lived within a 30-minute drive time to a JCPSC; 77% lived within a 60-minute drive time. Disparities in percentage of the population within 30-minute drive times were found by race/ethnicity, education, income, and urban/rural status; the disparity was largest between urban areas (70% lived within 30-minute drive time) and rural areas (26%). The rural coastal plains had the largest concentration of counties with high stroke death rates and the fewest JCPSCs.
Many areas in this tri-state region lack timely access to JCPSCs. Alternative strategies are needed to expand provision of quality acute stroke care in this region. GIS modeling is valuable for examining and strategically planning the distribution of hospitals providing acute stroke care.
PMCID: PMC3136973  PMID: 21672403

Results 1-6 (6)