Loss of cerebral white matter structural integrity tracks the gray matter metabolic decline in normal aging.

Relationships between structural MRI-based markers of declining cerebral integrity, and regional PET measurements of (18)FDG uptake have not been studied well in normal aging. In this manuscript we relate changes in cerebral morphology to regional cerebral glucose uptake for 14 major cortical areas in 19 healthy older individuals (age 59-92 years). Measurements of cerebral integrity included gray matter (GM) thickness, sulcal and intergyral spans, fractional anisotropy (FA) of water diffusion and volume of hyperintense WM (HWM) lesions. (18)FDG-PET measurements were converted to standard uptake values and corrected for partial volume artifact. Following this, cortical FDG uptake was significantly correlated with several indices of WM integrity that we previously observed to be sensitive to cognitive decline in executive function, including intergyral span and HWM volumes. Our findings suggest that the age-related decline in white matter integrity, observed as increases in HWM lesions, intergyral spans and reduction in FA, correlated with a decline in the global and regional cerebral glucose uptake. Our findings support the emerging consensus that WM integrity indices are sensitive predictors of declining cerebral health in normal aging. Specifically, age-related WM degradation in the thinly myelinated association tracts appears to track the decreases in global and regional rates of glucose uptake.

Assessing the executive function abilities of adults with neurogenic communication disorders.

Whereas it is known that executive function abilities are often impaired in clients having neurogenic communication disorders, few assessments of this cognitive domain are available that consider the speech and language deficits of this population. This article provides an overview of current procedures for assessing executive functions including a discussion of team approaches to assessment, a review of currently available neuropsychological and functional tests of executive function abilities, as well as a critique of those assessment procedures. In addition, suggestions are provided for how best to use or modify appropriately current tests of executive functioning for clients having acquired speech and language disorders as a result of brain damage.

Memory impairments in adults with neurogenic communication disorders.

Over the past few decades, there has been increasing interest in the nonlinguistic, cognitive abilities of adults with neurogenic communication disorders. In particular, a growing literature has documented deficits in a number of memory functions in this population. The purpose of this article is to summarize that literature and provide an overview of the presence and nature of memory impairments in aphasia, right hemisphere disorders, traumatic brain injury, and dementia. Ways that memory impairments may interact with the communication abilities of individuals with neurogenic communication disorders also are discussed.