Conversation so far:
What happened in 1988?
When Stephen Carpenter was 15 years old, he was hit by a car while skateboarding.
was he seriously injured?
Confined to a wheelchair for several months.
when was he rehabilitated?
he began teaching himself guitar by playing along to bands such as Anthrax, Stormtroopers of Death and Metallica.

Question: was he in the wheelchair at this time?
Self-contained rewrite: was Stephen Carpenter in a wheelchair during the early years?