Titration of gabapentin will be standardized as 300mg QHS and increased by 300mg every 3 days until taking 1200mg TID or maximum tolerable dose. Subjects will undergo cognitive evaluation prior to initiation of the medication, at 1 week (when titrated to approximately 900mg/day), 3 weeks (when titrated to approximately 2100mg/day), and at 6 weeks (when titrated to 3600mg/day or maximum tolerable dose).

Measure of cognitive functioning that assesses multiple dimensions central for effective functioning across adulthood: episodic memory, working memory, reasoning, verbal fluency, and executive functioning.

Scoring:

Word List Recall - Immediate & Delayed Total number unique is total number of correct responses (range 0-15)

Backward Digit Span Score is highest number of digits reached (range 0, 2-8)

Category Fluency Total number unique is total number of correct responses

Red/Green Accuracy Normal baseline score is total number correct in normal baseline condition (range 0-20) Number Series Total number of items correct (range 0-5)

Backward Counting Last number reached Total number of errors Total number of digits produced is calculated as: 100 - (number reached + number errors)

Medical questionnaire used to measure pain, developed by the Pain Research Group of the WHO Collaborating Center for Symptom Evaluation in Cancer Care 0-10 pain severity scale, 0=no pain, 10=pain as bad as you can imagine (scoring-a mean severity score) 0-10 pain relief scale, 0%=no relief, 100%=complete relief (only one question) 0-10 pain interference scale, 0=does not interfere, 10=completely interferes (scoring-mean of 7 items)