Knopman, David S.

Abstract In 2011, the National Institute on Aging and the Alzheimer's Association (NIA‐AA) proposed revising the criteria for diagnosing Alzheimer's disease (AD), which had been established more than 25 years earlier by the National Institute on Neurologic and Communicative Disorders and Stroke (NINCDS) and the Alzheimer's Disease and Related Disorders Association (ADRDA), now called the Alzheimer's Association. The NIA‐AA initiative also built upon research criteria for AD proposed by the International Working Group (IWG) in 2007 and updated in 2010. These efforts to revise the criteria reflect the need to improve diagnostic accuracy, facilitate clinical trials, and establish a common set of criteria that are universally accepted across domains of clinical practice, research, and drug development. To ensure that the proposed NIA‐AA criteria remain as current as possible, the Alzheimer's Association Research Roundtable convened a meeting in Washington, DC, on October 1 and 2, 2012, bringing together international stakeholders from industry, academia, and regulatory agencies to identify areas of agreement and research gaps respective of NIA‐AA criteria and IWG recommendations.

ABSTRACT Many people with rapid eye movement (REM) sleep behavior disorder (RBD) have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. Because gait disorders are common in the synucleinopathies, early abnormalities in gait in those with RBD could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment. We identified 42 probable RBD subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence, and stride dynamics with an automated gait analysis system. Cases and controls were similar in age (79.9 ± 4.7 and 80.1 ± 4.7, P = 0.74), Unified Parkinson's Disease Rating Scale Part III (UPDRS) score (3.3 ± 5.5 and 1.9 ± 4.1, P = 0.21) and Mini–Mental State Examination scores (27.2 ± 1.9 and 27.7 ± 1.6, P = 0.10). A diagnosis of probable RBD was associated with decreased velocity (−7.9 cm/s; 95% confidence interval [CI], −13.8 to −2.0; P < 0.01), cadence (−4.4 steps/min; 95% CI, −7.6 to −1.3; P < 0.01), significantly increased double limb support variability (30%; 95% CI, 6–60; P = 0.01), and greater stride time variability (29%; 95% CI, 2–63; P = 0.03) and swing time variability (46%; 95% CI, 15–84; P < 0.01). Probable RBD is associated with subtle gait changes prior to overt clinical parkinsonism. Diagnosis of probable RBD supplemented by gait analysis may help as a screening tool for disorders of α‐synuclein. © 2013 International Parkinson and Movement Disorder Society