Brain Injury Rehabilitation Specialists
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Medical Team

Physicians supervise the planning and implementation of each individual's comprehensive rehabilitation plan. Our rehabilitation teams work closely with these physicians and other specialists to maximize functional outcomes.


Dr. Ben Collins

Dr. Collins is an internal medicine physician and serves as On With Life's general Medical Director. Dr. Collins is at On With Life two days per week and is also on call 24/7.

Dr. Todd Troll

Dr. Troll is a physical medicine and rehabilitation physician with The Iowa Clinic and serves as On With Life's rehabilitation medical director. Dr. Troll is at On With Life four mornings a week and is on call 24/7.

Dr. Jerome Greenfield

Dr. Greenfield is a psychiatrist and works closely with the On With Life team to evaluate experiences and mood states to optimize rehabilitation outcomes. Dr. Greenfield is at On With Life one morning a week and is on call 24/7.

Dr. David Demarest

Dr. Demarest is our full-time, in-house neuropsychologist. As a neuropsychologist he uses scientific techniques to determine preexisting characteristics of the individual and provide an index of the extent and type of changes brought about by the injury or condition.