1 Traumatic brain injury (TBI) has been referred to as the signature wound of Operation Enduring Freedom and 2 Operation Iraqi Freedom (OEF/OIF) (Koehler et al., 2011). The consequences of TBI can be complex and 3 veterans with TBI exhibit a wide range of cognitive impairments including deficits of executive function and 4 memory (Sayer et al., 2008). TBI is also often accompanied by hearing loss and/or tinnitus in the majority of 5 TBI patients (Fausti, Wilmington, Gallun, Myers, & Henry, 2009) due to both cochlear damage and damage to 6 the central auditory system. Because hearing disorders disrupt both speech comprehension (Wilson et al., 7 2007) and working memory (Surprenant, 2007) it is essential to understand how hearing and memory interact 8 in patients with TBI. However, the connection between TBI-related hearing loss and TBI-related deficits in 9 memory has received relatively little study, despite research showing how other types of hearing loss, 10 particularly in older adults, can impact memory (McCoy et al., 2005; Miller & Wingfield, 2010). 11 To better understand the ultimate cause of the cognitive impairments associated with TBI, this project 12 will investigate auditory perception and cognition in veterans with TBI. We will investigate speech perception in 13 patient with TBI and evaluate the degree to which hearing deficits contribute to deficits in speech perception 14 and auditory working memory. We will also examine the relationship between the abnormalities in brain 15 structure and functional brain activation of TBI patients and their performance on tests of hearing, speech 16 perception and memory. The results will clarify the brain regions that play central roles in auditory cognition 17 and elucidate the peripheral and central factors that contribute to impaired cognition in TBI patients. 18 These aims serve to enhance the understanding of cognitive deficits that follow TBI and facilitate the 19 development of targeted rehabilitation. Although audiologic screening of TBI patients is not routine, previous 20 studies have found hearing abnormalities in more than 50% of patients with blast-related TBI (Lew et al., 21 2009). It is particularly useful to examine the incidence of hearing and phonological processing deficits in TBI 22 populations because audiological rehabilitation with hearing aids and perceptual training (Woods & Yund, 23 2007) can significantly improve speech comprehension. Identifying those patients who are likely to benefit from 24 hearing-based versus memory-based rehabilitation is thus a central goal of the current proposal. The analysis 25 of brain structural abnormalities with innovative structural MRI techniques will also add to the understanding of 26 the structural basis of TBI-related cognitive deficits. 27 This grant would serve as the beginning of Dr. Marc Ettlinger's independent research career at the VA. 28 This first project will provide the basis for future RR&D grants assessing the degree to which hearing training 29 and working memory training can contribute to TBI rehabilitation. The medium-term goal is to submit a Merit 30 Review award grant to RR&D in the final year of this proposed project addressing this issue. Dr. Ettlinger is an 31 ideal candidate to pursue this research because of his record publishing on neuroimaging (Ettlinger, et al., 32 submitted; Wong, et al., 2010), phonetics and phonology (Ettlinger & Johnson, 2009; Ettlinger et al., 2011) and 33 language and memory (Ettlinger et al., 2010; Ettlinger et al., in press). 34 The research will be conducted at VANCHCS, one of the leading centers in the VA for studying brain- 35 behavior relationships. The Neurology Research group at Martinez VA has unique patient resources and a 36 strong track record in cognitive neuropsychology. The Brain Imaging Center at the Martinez VA campus has 37 state of the art facilities for acquiring DT images and conventional structural scans. Mentor Dr. Woods is a 38 leading VA researcher on hearing impairment and mentor Dr. Baldo has worked extensively on TBI.
1 The main objective of this study is to improve rehabilitation methods for Veterans with traumatic brain injury 2 (TBI). Current treatments methods, such as Cognitive Rehabilitation Therapy, show some promise, but 3 evaluations of the shortcomings of current rehabilitation methods suggest that characterizing the specific 4 cognitive impairments of TBI patients is a crucial component of improving treatment. This project will do so by 5 investigating speech perception and memory deficits in Veterans with TBI. This project will also characterize 6 the structural abnormalities in the brain associated with these different deficits and differences in functional 7 brain activation in TBI patients compared to controls. Successful completion of the study will provide a set of 8 tools to direct rehabilitation methods in TBI patients. Instead of te current method of broad-based treatment, 9 this more detailed diagnosis of deficits can direct clinicians to instead direct focus on memory training or 10 speech perception training (American Speech-Language-Hearing Association, 1994; Jaeggi et al., 2008).
