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Holtzer Researches the Effects of Aging

Roee HoltzerDr. Roee Holtzer is professor of psychology and neurology and director of the PhD program in clinical psychology/health emphasis at Ferkauf Graduate School of Psychology.

His research lab examines the effects of age and age-related diseases on brain, cognitive, affective and functional outcomes, with a specific focus on cognitive and brain predictors of mobility outcomes such as walking and falls in older adults and disease populations.

Using functional Near-Infrared Spectroscopy (fNIRS), the lab developed methods that measure changes in brain activation patterns during walking tasks that manipulate cognitive demands (for example, Single-Task-Walk vs. Dual-Task-Walk conditions). The lab’s research has established the critical role of the prefrontal cortex in brain control of locomotion, notably under attention demanding conditions (e.g., Holtzer et al., 2015, NeuroImage, Holtzer et al., 2016, Brain Topography; Holtzer et al., 2017, European Journal of Neuroscience).

In several recent articles (all in 2018), his research has established the role of potentially modifiable risk factors on prefrontal cortex activation patterns and efficiency during active walking in older adults. These risk factors include the presence of diabetes, presence of polypharmacy (or the use of multiple medications) and, using multi-modal neuroimaging, the structural integrity of the brain’s white matter.

The research is being translated into tangible behavioral improvements. “In one recent article,” said Dr. Holtzer, “combining dual-task walking procedures, fNIRS and burst measurement (that is to say, repeated administration of the same measure), we have been able to demonstrate task-specific improvements in walking performance and its associated brain activation patterns and efficiency. This was the first study to demonstrate improved brain efficiency of walking. Participants became better at dual-task walking and used fewer brain resources to support their walking after a single training session. This finding has significant implication for our understanding of brain plasticity in aging, that is, how the aging brain can adapt and become more efficient, notably with relatively limited training. So, in a sense, old people can be taught new tricks (here, complex functional skills) rather quickly.”

Dr. Holtzer added that “the potential public health relevance of this research is that poor dual-task walking performance predicted increased risk of incident falls as well as frailty, disability and mortality in older adults. Moreover, higher mean prefrontal cortex activation, assessed with fNIRS, during dual-task walking predicted increased incident falls risk among healthy older adults. The findings reported in this manuscript suggest that dual-task walking performance and its associated prefrontal cortex activation efficiency can be improved in one session. Rehabilitation efforts could focus on improving performance and automaticity of dual-task walking, which in turn may improve brain efficiency, thereby reducing the risk of adverse mobility outcomes including but not limited to falls.”

Holtzer R, Izzetoglu M, Chen M, & Wang C. (2018). Distinct fNIRS-derived HbO2 trajectories during the course and over repeated walking trials under single and dual-task conditions: implications for within session learning and prefrontal cortex efficiency in older adults. Journal of Gerontology Medical Sciences, (Epub ahead of print).

George CJ, Verghese J, Izzetoglu M, Wang C, & Holtzer R. (2018). The effect of polypharmacy on prefrontal cortex activation during single and dual-task walking in community dwelling older adults. Pharmacological Research, (Epub ahead of print).

Lucas M, Wagshul ME, Izzetoglu M, & Holtzer R. (2018). Moderating Effect of White Matter Integrity on Brain Activation During Dual-Task Walking in Older Adults. Journal of Gerontology Biological Sciences,(Epub ahead of print).

Holtzer R, George CJ, Izzetoglu M, & Wang C. (2018). The effect of diabetes on prefrontal cortex activation patterns during active walking in older adults. Brain and Cognition,125, 14-22.