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E16 2012 ACRM–ASNR Annual Conference Abstracts

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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 sittingand standing. Main Outcome Measures: Differences in the MEPamplitude/slope of RC, and percent SICI and ICF were assessedbetween sitting and standing postures for FDI with comparison toproximal results previously collected with these same subjects. Re-ults: FDI testing showed no significant difference between posturesor recruitment curve outcome measures or intracortical inhibition oracilitation. Previous testing of the Anterior Deltoid (AD) showedhere were significant and consistent increases in RC slope and MEPmplitudes during standing compared to sitting. SICI/ICF testing forD revealed that in 4/5 subjects decreased inhibition was evident in

tanding compared to sitting position with little evidence of facilitationn standing. Conclusions: Our results suggest that motor corticalxcitability to proximal arm muscles is enhanced in standing comparedo sitting but is not generalized to representation for distaluscles. Key Words: Brain injury; Stroke; Diagnosis-independent;otor function; Neuroscience; Rehabilitation.

oster 5eft Dorsolateral Prefrontal Cortex Is Involved in Motor

magery. Dobrivoje S. Stokic (Methodist Rehabilitation Center,ackson, MS), Ina M. Tarkka.

isclosure: None disclosed.Objectives: Determine to what extent the left dorsolateral prefron-

tal cortex (PFC) contributes to facilitation in the primary motor cortexarea (M1) of the muscle involved in motor imagery. Design: Trans-cranial magnetic stimulation to the left M1 (round coil at Cz, 120%resting threshold, 85�10% of maximal output) was used to elicitresponses in the right tibialis anterior (TA) muscle during relaxationand while imagining right ankle dorsiflexion movements cued by avisual display. A second stimulator (figure-8 coil at F3, 75�10%) wasused to stimulate the left PFC 300ms before M1 during relaxation andmotor imagery. Setting: Research lab in a non-profit rehabilitationcenter. Participants: Five healthy adults (age 57�6 years). Interven-tions: Stimulation of the left PFC during motor imagery to induce avirtual lesion. Main Outcome Measures: Amplitude of the motorevoked potentials (MEPs) in the right TA muscle during relaxation andmotor imagery, without and with the left PFC stimulation (8-12 traceseach). Results: Motor imagery significantly increased MEPs in theright TA compared to relaxation (�400% on average). Stimulating theleft PFC 300ms before the M1 significantly reduced the facilitatoryeffect of motor imagery by about one quarter (317%, p�0.0268).However, paired left PFC and M1 stimulation during relaxation had noappreciable effect on MEPs (102%). Conclusions: The left dorsolat-eral PFC is a part of the network involved in motor imagery, perhapsthrough its role in kinesthetic working memory. Impaired output fromthis area may hinder the potential to utilize motor imagery for resto-ration of motor function. Key Words: Diagnosis-independent; Motorfunction; Neuroscience; Rehabilitation.

Poster 6Hyoid Movement During Stage II Food Transport From Mouth toPharynx. 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 IItransport (St2Tr). St2Tr is frequent in normal eating, yet its mecha-nism is poorly understood. We examined movements of the hyoidbone during St2Tr cycles in comparison to ordinary chewing orswallowing. Design: Prospective study. Setting: Radiology suite. Par-ticipants: 13 healthy adult volunteers. Intervention: Videofluoros-copy was performed in lateral projections while subjects ate six gportions of cookie, banana and tofu with barium. Recordings were

divided into jaw motion cycles classified as St2Tr, chewing or swal-lowing cycles. Main Outcome Measures: The vertical and horizontal

rch 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 � 4.2mm) 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 andchewing cycles (p � 0.50). Conclusion: The displacement patterns ofthe hyoid bone differed substantially among the three types of cycles.Vertical displacement differentiated St2Tr from chewing and swallow-ing cycles. We suggest that the upward displacement of the hyoid boneis necessary for the upward movement of the tongue surface associatedwith squeezing the bolus against the palate. This squeezing is essentialfor bolus propulsion from the oral cavity to the pharynx. Key Words:Diagnosis-independent; Function and impairment-independent;Rehabilitation.

Poster 7The Role of Cognitive Reserve in Memory and Executive Func-tioning: Cypriot Neurocognitive Study on Aging. Fofi Const-antinidou (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 executivefunctioning (EF) in neurologically healthy older adults. A latent vari-able model for CR was implemented to test the hypotheses stating thatCR plays a moderating role on the relationship between age andcognitive functions in healthy aging.

Design: A longitudinal prospective cohort study. Setting: Commu-nity. 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 baselineand at two years. Main Outcome Measures: Neuropsychologicalbattery of EF, memory, language and QOL measures. Results: Con-firmatory factor analyses validated latent constructs representing twoneuropsychological domains (VEP and EF) and a measure of CR. Twostructural equation models (SEM) were evaluated. The first SEMtested the direct relationships between age and two latent variablesreflecting VEP and EF. Adequate model fit and negative associationsamong age and both cognitive domains were obtained. The secondSEM included CR as a moderator also had acceptable fit. Resultsdemonstrated that CR strongly moderated the relationship between ageand cognitive functions as following: (i) the strength of the (negative)relationship between age and episodic memory was reduced; (ii) thedirect path from age to executive functions was no longer statisticallysignificant and (iii) all indirect paths were statistically significant.Conclusions: Findings support the CR hypothesis and its moderatoreffect on VEP and EF in normal aging. Implications for the theoreticalunderstanding of CR on healthy and pathological aging are discussed.It is possible that high levels of CR can help delay the onset ofobserved clinical symptomatology in adults with mild cognitiveimpairment. Key Words: Neurodegenerative disorder; Lifespan is-sues; Neuroscience; Rehabilitation.

Poster 8Assessment of Improvement of Functional Status of Chronic Guil-lain-Barré Syndrome With 4-Aminopyridine – Phase IIAStudy. Jay Meythaler (Wayne State University, Detroit, MI, Oak-wood Hospital, Dearborn, MI), Saurabha Bhatnagar.

Disclosure: Jay Meythaler discloses potential patent royalties to theUniversity that may be shared with discoverer, principle investigator,Patent filed by University in my name. Saurabha Bhatnagar discloses4-Aminopyridine.

Objective: To investigate whether orally administered 4-aminopyr-idine (4-AP) is safe and effective in improving motor function in

patients with Guillain-Barré syndrome (GBS). Design: This was aPhase IIA randomized, double-blinded, placebo-controlled, crossover,