Methylphenidate (Ritalin) and Memory/Attention in Traumatic Brain Injury (TBI)

Overview

Traumatic brain injury (TBI) is a significant public health problem, with 1.5-2.0 million Americans injured each year. Cognitive deficits, particularly in the domains of memory and attention are frequently the source of lingering disability after TBI and a source of enormous distress to the injured individuals and their family/caregivers. To date, interventions to ameliorate chronic cognitive deficits have been directed at either pharmacological interventions or cognitive rehabilitation. We propose to (1) To compare the efficacy of three interventions: memory and attention training (MAAT), methylphenidate, and memory/attention training in combination with methylphenidate and (2) use functional MRI (fMRI) to characterize changes in activation of the neural circuitry of memory and attention due to MAAT alone, methylphenidate alone, and MAAT in combination with methylphenidate. This is a two by two design with medication (methylphenidate/placebo) and cognitive therapy (Memory and Attention Training (MAAT) or an Attention control intervention) as possible interventions. Using a randomized, placebo-controlled, double-blind design, 200 individuals with persistent cognitive deficits 6-12 months after MTBI will be randomized to receive a six week trial of either (1) MAAT and placebo, (2) MAAT and methylphenidate (0.3 mg/kg BID), (3) attention control intervention and methylphenidate (0.3 mg/kg BID), or (4) attention control intervention and placebo. Symptom distress, attention and memory performance, and activation patterns of the neural circuitry of attention and memory while undergoing fMRI will be characterized at baseline, and after the four treatment conditions. This study will provide important information on three interventions for the most disabling sequelae of an enormous public health problem. Further, it will help to clarify underlying neural mechanisms and suggest additional treatment possibilities.

Summary and Gaps to be Addressed by the Proposed Study What is known: There are two interventions of promising efficacy in ameliorating deficits in attention and memory after mild traumatic brain injury (MTBI): (i) memory and attention training/rehabilitation, and (ii) catecholaminergic augmentation (particularly with methylphenidate - which augments both dopaminergic and adrenergic systems). fMRI and other functional imaging strategies are providing valuable insights into the underlying neural mechanisms of the cognitive enhancing effects of methylphenidate in some neuropsychiatric populations (individuals with ADHD), and the effects of cognitive rehabilitation efforts in some domains (e.g. speech and language in individuals after stroke). What is not known: To date there are no studies that apply a psychopharmacological strategy of augmenting neurotransmitter systems known to modulate memory/attention (dopaminergic and adrenergic systems) in combination with a cognitive rehabilitation intervention known to improve memory/attention (memory/attention training) in individuals with MTBI. We are aware of no published studies that use fMRI to assess the neural mechanisms of memory/attention improvement from the use of catecholaminergic agents or memory/attention training in individuals with MTBI. It is important to determine the efficacy of combined memory/attention training and methylphenidate. It is equally important to begin to understand the neural mechanisms underlying effective treatment as it may help to inform the development of the next generation of interventions and perhaps lead to individually tailored treatment interventions. This proposal will start to address these gaps in our knowledge.