RC

E16

2012 ACRM–ASNR Annual Conference Abstracts

with no history of seizures or neurological disability. Interventions: Recruitment curves (RC), intracortical inhibition and facilitation (SICI, ICF) were assessed for first dorsal interosseus (FDI) in sitting and standing. Main Outcome Measures: Differences in the MEP amplitude/slope of RC, and percent SICI and ICF were assessed between sitting and standing postures for FDI with comparison to proximal results previously collected with these same subjects. Results: FDI testing showed no significant difference between postures for recruitment curve outcome measures or intracortical inhibition or facilitation. Previous testing of the Anterior Deltoid (AD) showed there were significant and consistent increases in RC slope and MEP amplitudes during standing compared to sitting. SICI/ICF testing for AD revealed that in 4/5 subjects decreased inhibition was evident in standing compared to sitting position with little evidence of facilitation in standing. Conclusions: Our results suggest that motor cortical excitability to proximal arm muscles is enhanced in standing compared to sitting but is not generalized to representation for distal muscles. Key Words: Brain injury; Stroke; Diagnosis-independent; Motor function; Neuroscience; Rehabilitation. Poster 5 Left Dorsolateral Prefrontal Cortex Is Involved in Motor Imagery. Dobrivoje S. Stokic (Methodist Rehabilitation Center, Jackson, MS), Ina M. Tarkka. Disclosure: None disclosed. Objectives: Determine to what extent the left dorsolateral prefrontal cortex (PFC) contributes to facilitation in the primary motor cortex area (M1) of the muscle involved in motor imagery. Design: Transcranial magnetic stimulation to the left M1 (round coil at Cz, 120% resting threshold, 85⫾10% of maximal output) was used to elicit responses in the right tibialis anterior (TA) muscle during relaxation and while imagining right ankle dorsiflexion movements cued by a visual display. A second stimulator (figure-8 coil at F3, 75⫾10%) was used to stimulate the left PFC 300ms before M1 during relaxation and motor imagery. Setting: Research lab in a non-profit rehabilitation center. Participants: Five healthy adults (age 57⫾6 years). Interventions: Stimulation of the left PFC during motor imagery to induce a virtual lesion. Main Outcome Measures: Amplitude of the motor evoked potentials (MEPs) in the right TA muscle during relaxation and motor imagery, without and with the left PFC stimulation (8-12 traces each). Results: Motor imagery significantly increased MEPs in the right TA compared to relaxation (⬃400% on average). Stimulating the left PFC 300ms before the M1 significantly reduced the facilitatory effect of motor imagery by about one quarter (317%, p⫽0.0268). However, paired left PFC and M1 stimulation during relaxation had no appreciable effect on MEPs (102%). Conclusions: The left dorsolateral PFC is a part of the network involved in motor imagery, perhaps through its role in kinesthetic working memory. Impaired output from this area may hinder the potential to utilize motor imagery for restoration of motor function. Key Words: Diagnosis-independent; Motor function; Neuroscience; Rehabilitation. Poster 6 Hyoid Movement During Stage II Food Transport From Mouth to Pharynx. Mitsumasa Yoda (Johns Hopkins University, Baltimore, MD). Disclosure: None disclosed. Objective: When eating solid food, small portions of triturated food are propelled into the oropharynx before swallowing via stage II transport (St2Tr). St2Tr is frequent in normal eating, yet its mechanism is poorly understood. We examined movements of the hyoid bone during St2Tr cycles in comparison to ordinary chewing or swallowing. Design: Prospective study. Setting: Radiology suite. Participants: 13 healthy adult volunteers. Intervention: Videofluoroscopy was performed in lateral projections while subjects ate six g portions of cookie, banana and tofu with barium. Recordings were divided into jaw motion cycles classified as St2Tr, chewing or swallowing cycles. Main Outcome Measures: The vertical and horizontal Arch Phys Med Rehabil Vol 93, October 2012

components of hyoid displacement during each type of cycle. Results: Vertical hyoid displacement was greatest during swallowing (13.5 ⫾ 3.4 mm; mean ⫾ SD, p ⬍ 0.01), intermediate during St2Tr (8.4 ⫾ 4.2 mm) and smallest during chewing cycles (5.9 ⫾ 3.5 mm, p ⬍ 0.01). Horizontal hyoid displacement was greater during swallowing (13.0 ⫾ 2.9 mm) than during St2Tr (4.3 ⫾ 1.9 mm) or chewing cycles (4.3 ⫾ 2.3 mm, p ⬍ 0.01), but did not differ significantly between St2Tr and chewing cycles (p ⫽ 0.50). Conclusion: The displacement patterns of the hyoid bone differed substantially among the three types of cycles. Vertical displacement differentiated St2Tr from chewing and swallowing cycles. We suggest that the upward displacement of the hyoid bone is necessary for the upward movement of the tongue surface associated with squeezing the bolus against the palate. This squeezing is essential for bolus propulsion from the oral cavity to the pharynx. Key Words: Diagnosis-independent; Function and impairment-independent; Rehabilitation. Poster 7 The Role of Cognitive Reserve in Memory and Executive Functioning: Cypriot Neurocognitive Study on Aging. Fofi Constantinidou (University of Cyprus, Nicosia, Cyprus). Disclosure: None disclosed. The study examined the cognitive reserve (CR) hypothesis in association with age, verbal episodic memory (VEP), and executive functioning (EF) in neurologically healthy older adults. A latent variable model for CR was implemented to test the hypotheses stating that CR plays a moderating role on the relationship between age and cognitive functions in healthy aging. Design: A longitudinal prospective cohort study. Setting: Community. Participants: 253 Greek-Cypriot older healthy older adults (Mean age⫽ 75.12, SD⫽6.19; Mean years of education⫽6.96, SD⫽4.11). Intervention: Neuropsychological assessment at baseline and at two years. Main Outcome Measures: Neuropsychological battery of EF, memory, language and QOL measures. Results: Confirmatory factor analyses validated latent constructs representing two neuropsychological domains (VEP and EF) and a measure of CR. Two structural equation models (SEM) were evaluated. The first SEM tested the direct relationships between age and two latent variables reflecting VEP and EF. Adequate model fit and negative associations among age and both cognitive domains were obtained. The second SEM included CR as a moderator also had acceptable fit. Results demonstrated that CR strongly moderated the relationship between age and cognitive functions as following: (i) the strength of the (negative) relationship between age and episodic memory was reduced; (ii) the direct path from age to executive functions was no longer statistically significant and (iii) all indirect paths were statistically significant. Conclusions: Findings support the CR hypothesis and its moderator effect on VEP and EF in normal aging. Implications for the theoretical understanding of CR on healthy and pathological aging are discussed. It is possible that high levels of CR can help delay the onset of observed clinical symptomatology in adults with mild cognitive impairment. Key Words: Neurodegenerative disorder; Lifespan issues; Neuroscience; Rehabilitation. Poster 8 Assessment of Improvement of Functional Status of Chronic Guillain-Barré Syndrome With 4-Aminopyridine – Phase IIA Study. Jay Meythaler (Wayne State University, Detroit, MI, Oakwood Hospital, Dearborn, MI), Saurabha Bhatnagar. Disclosure: Jay Meythaler discloses potential patent royalties to the University that may be shared with discoverer, principle investigator, Patent filed by University in my name. Saurabha Bhatnagar discloses 4-Aminopyridine. Objective: To investigate whether orally administered 4-aminopyridine (4-AP) is safe and effective in improving motor function in patients with Guillain-Barré syndrome (GBS). Design: This was a Phase IIA randomized, double-blinded, placebo-controlled, crossover,