Mary M. Machulda

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Numerous kindreds with familial frontotemporal dementia and/or amyotrophic lateral sclerosis have been linked to chromosome 9, and an expansion of the GGGGCC hexanucleotide repeat in the non-coding region of chromosome 9 open reading frame 72 has recently been identified as the pathogenic mechanism. We describe the key characteristics in the probands and(More)
OBJECTIVE To determine whether an fMRI memory encoding task distinguishes among cognitively normal elderly individuals, patients with mild cognitive impairment (MCI), and patients with early Alzheimer's disease (AD). METHODS Twenty-nine subjects (11 normal, 9 MCI, 9 AD) were studied with an fMRI memory encoding task. A passive sensory task was also(More)
Task-free functional magnetic resonance imaging (TF-fMRI) has great potential for advancing the understanding and treatment of neurologic illness. However, as with all measures of neural activity, variability is a hallmark of intrinsic connectivity networks (ICNs) identified by TF-fMRI. This variability has hampered efforts to define a robust metric of(More)
OBJECTIVE To investigate age-related default mode network (DMN) connectivity in a large cognitively normal elderly cohort and in patients with Alzheimer disease (AD) compared with age-, gender-, and education-matched controls. METHODS We analyzed task-free-fMRI data with both independent component analysis and seed-based analysis to identify anterior and(More)
OBJECTIVE To examine default mode and salience network functional connectivity as a function of APOE ε4 status in a group of cognitively normal age-, sex-, and education-matched older adults. DESIGN Case-control study. SUBJECTS Fifty-six cognitively normal APOE ε4 carriers and 56 age-, sex- and education-matched cognitively normal APOE ε4 noncarriers.(More)
Apraxia of speech is a disorder of speech motor planning and/or programming that is distinguishable from aphasia and dysarthria. It most commonly results from vascular insults but can occur in degenerative diseases where it has typically been subsumed under aphasia, or it occurs in the context of more widespread neurodegeneration. The aim of this study was(More)
OBJECTIVE We assessed whether clinical and imaging features of subjects with apraxia of speech (AOS) more severe than aphasia (dominant AOS) are more similar to agrammatic primary progressive aphasia (agPPA) or to primary progressive AOS (PPAOS). METHODS Sixty-seven subjects (PPAOS = 18, dominant AOS = 10, agPPA = 9, age-matched controls = 30) who all had(More)
IMPORTANCE Typical cognitive aging may be defined as age-associated changes in cognitive performance in individuals who remain free of dementia. Ideally, the full adult age spectrum should be included to assess brain imaging findings associated with typical aging. OBJECTIVE To compare age, sex, and APOE ε4 effects on memory, brain structure (adjusted(More)
The objective of this study was to examine practice effects and longitudinal cognitive change in a population-based cohort classified as clinically normal at their initial evaluation. We examined 1390 individuals with a median age of 78.1 years and re-evaluated them up to four times at approximate 15-month intervals, with an average follow-up time of 5(More)
BACKGROUND The association between gait speed and cognition has been reported; however, there is limited knowledge about the temporal associations between gait slowing and cognitive decline among cognitively normal individuals. METHODS The Mayo Clinic Study of Aging is a population-based study of Olmsted County, Minnesota, United States, residents aged(More)