Neurology News
Follow our Neurology News blog for the latest news on neurologic diseases and research.

Thursday, May 18, 2017

BY SARAH OWENS

A dual test measuring the ability of older people with mild cognitive impairment (MCI) to perform a cognitive task while walking predicted their progression to dementia, according to a new study published online on May 15 in JAMA Neurology.

Research has shown that slowing of gait is both one of the earliest symptoms of Alzheimer's disease and helps predict progression to dementia in the general population. However, although dementia involves both cognitive and motor dysfunction, and cognition and motor control share common brain networks, few studies have measured the association between cognitive-motor interaction and progression to dementia.

If the findings are validated in other MCI cohorts, they support "adding dual-task gait testing to the clinical and cognitive evaluation of patients with MCI to improve dementia prediction," the study authors, led by Manuel M. Montero-Odasso, MD, PhD, FRCPC, associate professor of medicine, epidemiology and biostatistics at the University of Western Ontario and director of the Gait and Brain Lab at Parkwood Institute in London, Ontario, wrote.

For the study, researchers at the Gait and Brain Lab assessed data on 112 study participants in the Gait and Brain Study, an ongoing, prospective study designed to measure the relation between quantitative gait deficits and cognitive and mobile decline in community-dwelling older adults. All participants were 65 years of age or older, had been diagnosed with MCI, and were able to walk 10 meters without a cane at the start of the study.

Twice a year for six years, all participants underwent a neuropsychological test battery and tests of global cognition, executive function, verbal episodic memory, naming skill, attention, and working memory. Also twice a year, the researchers assessed the participants' gait using an electronic walkway that assessed both spatial and temporal parameters of walking ability. Participants were asked to walk at their usual pace without the use of mobility aids.

Two types of gait tests were administered: A single-gait test, for which participants walked without performing any cognitive tasks, and a dual-task test, for which participants walked while performing a number of cognitive tasks aloud. These tasks included counting backward from 100 by ones; subtracting serial sevens from 100; and naming animals.

At the end of the six-year follow-up period, the researchers found that 24 percent of the participants had progressed to dementia. Slow performance on the single-gait test (slower than 0.8 meters per second) was not associated with dementia (hazard ratio [HR], 3.41; 95% CI, 0.99-11.71; p=0.5). However, worse performance on the dual-task gait test while counting backward (HR, 3.79; 95% CI, 1.57-9.15; p=0.003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; p=0.04) were both associated with progression to dementia.

The findings, the study authors concluded, suggest that poor performance on a dual-task gait test is linked with a 2- to 3-times higher risk of progressing to dementia in people with MCI. Since the test is easy to administer, they added, it "may be used to clinicians to decide further biomarker testing, preventive strategies, and follow-up planning in patients with MCI."

The researchers noted several limitations to their study. Among them were the small sample size of 112 participants, the low frequency of outcome events, and the need to cross-validate the findings in other MCI cohorts.

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Wednesday, May 10, 2017

BY SARAH OWENS

Patients who underwent truncal vagotomy, which denervates multiple organs, including the stomach, liver, gall bladder, and pancreas, appeared to have a decreased risk of Parkinson's disease (PD). And the evidence suggests truncal vagotomy may delay the onset of PD, according to a new study published online on April 26, 2017 ahead of the print edition of Neurology.

The authors were interested in exploring the evidence of Parkinson's disease pathology in the gut based on human and animal studies. In pathologic studies, Lewy-type pathology has been found in the gut of people with prodomal Parkinson's disease. Their interest in examining the effect of vagotomy was spurred by mouse models, in which vagal surgery was observed to stop the spread of PD-like pathology.

The authors of the study, led by Bojing Liu, MSc, of the department of medical epidemiology and biostatistics at the Karolinska Institute in Stockholm, Sweden, noted that the association was not significant overall for other types of vagotomy.  The findings offer "suggestive evidence for a potential protective effect of truncal, but not selective, vagotomy against PD development," they wrote.

The PD risk reduction was strongest at more than five years and more than 10 years after vagotomy, but the association was attenuated at more than 20 years after vagotomy. These temporal patterns, the study authors suggested, support "the possibility that PD pathology may start at multiple sites of the peripheral nervous system" and that truncal vagotomy may delay, rather than entirely prevent, the onset of PD.

For the study, researchers gathered data from nationwide health registries in Sweden and matched 9,430 patients who underwent vagotomy between 1970 and 2010 with 377,200 reference individuals by sex and year of birth. Of the patients who underwent vagotomy, 3,445 underwent a truncal vagotomy, and 5,978 underwent a selective vagotomy,which denervates only the stomach and preserves innervation to the antrum and pylorus.

They followed up the participants from the date of vagotomy until diagnosis of PD, death, emigration out of Sweden, or the end of 2010 (whichever occurred first), using the Swedish Patient Register to identify all vagotomies and all cases of incident PD.

They found that among 4,390 total cases of incident PD over 7.3 million person-years, the incidence of PD was 61.8 per 100,000 person-years among participants who underwent vagotomy and 67.5 per 100,000 person-years among the reference participants. There was no overall association between vagotomy and PD risk, but patients who underwent truncal, rather than selective, vagotomy appeared to have a lower PD risk (HR 0.78, 95% CI 0.37-0.93), although the difference did not reach statistical significance.

The researchers noted several limitations to their study. Among them, the nationwide registry likely included misclassifications, especially of Parkinson's diagnosis and the timing of diagnosis; and they were unable to fully control for all confounders, including individual Parkinson's disease risk factors like smoking, coffee intake, and genetics.

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Friday, May 5, 2017

BY SARAH OWENS

Neurology Today was awarded the top Gold Award for Best Single News/Analysis, for the article, "Salary Disparities Reported Between Men and Women Academic Physicians — The Widest Gap Is in Neurology" (http://bit.ly/NT-salarydisparities; August 18, 2016) in this year's editorial competition sponsored by the American Society of Healthcare Publication Editors (ASHPE).

Written by Dawn Fallik, a professor of journalism at the University of Delaware and former health reporter with the Philadelphia Inquirer, the article examines salary disparities that were reported in a 2016 study in the Journal of the American Medical Association: The gap was found to be particularly wide between women and men neurology professors.

In the article, female neurologists weigh in on the report's findings, offering insights on lessons learned from their own experiences in academic neurology. They say, among other factors, that differences in negotiating styles and tactics may account for some of the challenges in ensuring salary parity.  

The ASHPE awards recognize excellence in the field of healthcare publishing and are awarded by a jury of editors and publishing professionals.

For more on Neurology Today's coverage of salary disparities, visit bit.ly/NT-salariesforwomen​.


Friday, April 7, 2017

BY SARAH OWENS

The performance of patients with mild cognitive impairment varied greatly in an analysis of seven randomized controlled trials, according to a new study published in the April 5 online edition of Neurology. Variability in the criteria for enrolling patients, study design, and outcomes assessments may have contributed to the wide-ranging results, the study authors said.  

 "While the studies appeared to be designed in a similar fashion, subtle entry, exit, and procedural differences led to vastly different outcomes for the participants," the study authors, led by Ronald C. Petersen, PhD, MD, wrote. "The implementation of continuous outcome measures rather than clinical states may improve performance of trials," they added, "but clinical meaningfulness needs to be established."

For their study, researchers obtained data on placebo groups from 7 randomized, controlled trials of patients with MCI and collated the data for common measurement instruments. Using the Alzheimer's Disease Assessment Sale-cognitive subscale (ADAS-cog), the Mini-Mental State Examination (MMSE), and the Clinical Dementia Rating-sum of boxes (CDR-SB), the researchers tracked the performance of patients in the placebo arms and measured their progression to prespecified clinical study endpoints.

They found that although similar criteria for MCI were used in the trials, the implementation of those criteria varied significantly. For example, all studies used the ADAS-cog to measure cognition, but in some studies the patients in the placebo group with MCI had worsening cognition on this scale, while patients in other studies appeared to improve. Results on the MMSE and the CDR-SB "appeared to corroborate the ADAS-cog findings": Some patients appeared to worsen in a predictable manner, but others remained stable or improved.

Additionally, researchers examined the effect of APOE4 carrier status on the results, finding that, as expected, APOE4 carriers had worse cognitive performance on all scales.

The results, the study authors concluded, suggest that minor variations in methodology can lead to significant variations in outcomes among patients in the placebo group, which vastly limits efficacy findings. As for the source of these variations, the researchers suggested that differences in the implementation of instruments like the ADAS-cog in order to characterize participants, and subtle variations in study populations, likely play a role. Differences in language, culture, and the prevalence of comorbidities may also contribute, they noted, adding that future trials should address these issues.

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  • Peterson RC, Thomas RG, Aisen PS, et al. Randomized controlled trials in mild cognitive impairment: Sources of variability. Neurology 2017; Epub 2017 Apr 5.​

Friday, March 31, 2017

BY SARAH OWENS

The combined annual cost of neurological diseases in the United States totals almost $800 billion, and it can be expected to rise rapidly due to an aging population, according to a new summary report published online on March 29 in the Annals of Neurology.

The current report identifies the annual costs associated with different neurological disease types, and projects rising costs over the coming years as the elderly population is expected to double by 2050.

"Given the extraordinary and rapidly growing costs of neurological disorders themselves, a concrete strategy is urgently needed to reduce the burden is neurological disease," the study authors, led by Clifton L. Gooch, MD, professor and chair of neurology at the University of South Florida (USF) Morsani Medical College, wrote.

To assess the total cost burden in the US by disease type, researchers at USF conducted a detailed review of published literature, analyzing the most prevalent and the costliest neurological diseases. They excluded diseases that have mixed etiologies, such as depression and chronic pain, they said, because they would have  pushed cost estimates substantially higher.

For each disease category, they accounted for and extrapolated per-patient costs for care and lost productivity as levels of disability increased.

They found that among the costliest were Alzheimer's disease and related dementias, incurring annual costs of $243 billion for informal and home-based care; chronic low back pain, $177 billion; stroke, nearly $110 billion when accounting for primary costs and indirect costs such as loss of productivity; and traumatic brain injury, $86 billion per year.

Among the steps the study authors suggest to offset these costs was to accelerate translational research in preventive and disease-modifying therapies; this would help delay the onset of symptoms that are costly to treat or manage, they wrote. For example, they noted that deploying efforts to control risk factors for stroke — prescribing antihypertensive and statin therapies had decreased the incidence of stroke. A new treatment delaying Alzheimer's disease by as much as 10 years could potentially save a projected $175 billion dollars annually.

They also encouraged enhanced research into outcomes and comparative effectiveness, which would help eliminate costly and unnecessary research; in particular, they cited the Patient Centered Outcomes Research Initiative (PCORI), as an effective venue for such research, though they acknowledged that it is insufficiently funded to enable meaningful progress, 

Among other nitiatives, the study authors suggested comprehensive tracking of neurological diseases through databases, which could be used to gauge the success of new strategies; and enhanced advocacy efforts on individual, state and federal government levels to urge funding and implementation of these initiatives.

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