Comparison of the Checkerboard P300 Speller vs. the Row-Column Speller in Normal Elderly and an Aphasic Stroke Population (S21.006)

OBJECTIVE: This study evaluates the ability of patients with Broca’s aphasia due to stroke to use two different P300 visual spellers to communicate. BACKGROUND: One major goal of current P300 visual speller research is to develop paradigms that significantly improve communication in patients suffering from severe neurologic disorders impairing speech and motor function. Most of the past clinical research subjects were patients with ALS or locked-in syndrome. Stroke is the leading cause of neurologic disease in the United States and those causing aphasias or language dysfunction are some of the most disabling. Restoring effective communication for stroke patients, especially for patients with expressive aphasia, is another potential application for BCI. METHODS: Prospective case-control study of 17 individuals:Nine normal elderly subjects and eight stroke patients with Broca’s aphasia. All stroke subjects had a NIH stroke scale language subscore of 2 or greater. All stroke subjects understood spoken language and were able to sign a Mayo Clinic IRB-approved consent form. EEG was recorded using a standard 32-channel electrode cap, amplified, band pass filtered 0.5-500 Hz and digitized at 1200 Hz using g.USB amplifiers (Guger Technologies). Subjects attempted to spell words by using the checkerboard (CBP) and row-column (RCP) paradigms on a 6x6 alphanumeric matrix. Stimulus presentation and data recording were controlled by BCI2000. RESULTS: Stroke subjects achieved a spelling accuracy of 60-65%. Normals achieved a higher accuracy than stroke subjects with the CBP (median 91% vs. 66%; range 55-100% vs. 36-98%; p < 0.01). CBP was also preferred over the RCP by normals, had a higher accuracy rate and was judged to be easier to perform. CONCLUSION: Our study demonstrates that stroke patients with Broca’s aphasia can use a P300 visual speller to communicate. Our results also indicate that in the elderly population, CBP is a superior paradigm compared to RCP. Disclosure: Dr. Shih has received research support from Eisai Inc., and Visualase Inc. Dr. Townsend has nothing to disclose. Dr. Krusienski has nothing to disclose. Dr. Shih has nothing to disclose. Dr. Shih has nothing to disclose. Dr. Heggeli has nothing to disclose. Dr. Paris has nothing to disclose. Dr. Meschia has nothing to disclose.