Date of Award

1-1-2013

Document Type

Open Access Dissertation

Department

Exercise Science

First Advisor

Roger Newman-Norlund

Abstract

Brain stimulation techniques capable of optimizing cortical plasticity may provide the key to improved therapeutic techniques and functional outcomes. The primary aim of this dissertation was to examine the potential of motor training (MT) augmented with intermittent theta burst stimulation (iTBS) and anodal transcranial direct current stimulation (a-tDCS). The secondary aim was to investigate whether the training would also be advantageous to older-adults. We hypothesized that right-handed, college-age students exposed to the treatment (n=17) would perform better short-term (directly following MT) and long-term (24 hours and 7 days following MT) on motor-skill retention tests than students receiving sham stimulation (n=14). We also hypothesized that older adults (n=9) exposed to iTBS/a-tDCS enhanced MT would demonstrate greater functional improvements than younger adults (n=16) receiving identical stimulation. iTBS and a-tDCS over the non-dominant motor cortex were used as a primer to, and in conjunction with, 20-minutes of non-dominant, upper extremity MT, respectively. The Jebsen-Taylor Hand Function Test (JTHF) was chosen as the primary outcome measure, while the Pursuit Rotor Tracking Test (PRTT), Purdue Pegboard Test (PPB), and Fitt's Reciprocal Tapping Test (FRTT) were considered secondary outcome measures. Students receiving iTBS/a-tDCS enhanced MT made significantly greater improvements on the JTHF than the placebo-control group (p = .041). However, differences in improvement between the groups were primarily seen long-term (p-.045). Secondary outcome measures were not sensitive enough to detect a difference between the groups at any time point. Concerning the overall performance of older vs. younger participants, whose training was augmented by iTBS/a-tDCS, neither group improved more than the other on the JTHF (p= .1801). The older group scored better on the PRTT (p = .016) and the PPB (p = .0036) but not the FRTT. Although there was no short-term performance difference on any outcome measure, older adults made greater functional improvements than younger adults long-term on the PPB (p = .0039), PPB (p = .0008) and JTHF (p = .0384) (7 days post-treatment). Collectively, the results suggest that brain stimulation may be a useful adjunct to MT in healthy, younger and older adults. Brain stimulation may also eventually improve PT outcomes of neurologically-impaired patients.

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