A brain-computer interface (BCI) is a device that has the potential to restore communication by translating voluntarily controlled brain signals of intent. The P300 speller, a popular BCI paradigm, relies on the generation of a P300 evoked potential when a user is presented a rare and unpredictable target stimulus amidst a larger pool of non-target stimuli. This evoked potential is used to control a spelling interface. Those with advanced ALS experiencing the loss of voluntary muscular control may also experience cognitive changes that result in decreased capacity for BCI control using the P300 speller. With this pilot study, we aim to validate the performance of a combination of eye tracking and standard sensory testing to quantify intact sensory and cognitive processes necessary for the generation of a P300 response. Additionally, we will evaluate the association of these correlates with performance on a multisensor P300 spelling task, where brain potentials are evoked using a combination of visual, auditory, and tactile stimuli. The goal is to demonstrate the viability of this system for future use in a patient group.