Clinical Trial: Central Auditory Processing Deficits Associated With Blast Exposure

Study Status: Completed
Recruit Status: Completed
Study Type: Observational [Patient Registry]

Official Title: Central Auditory Processing Deficits Associated With Blast Exposure

Brief Summary: The current conflicts in Afghanistan and Iraq have resulted in unprecedented rates of exposure to high-intensity blasts and resulting brain injury. This research team has established that recently blast-exposed Soldiers show differences from controls on tests of central auditory function. This project will 1) develop a more accurate estimate of the prevalence of central auditory dysfunction among Veterans exposed to blasts over the past ten years, 2) identify the functional outcomes associated with abnormal performance on tests of central processing, and 3) improve understanding of the ways in which blast-exposure resembles and differs from both the normal aging process and non-blast-related TBI in terms of performance on tests of central auditory processing.

Detailed Summary:

The current conflicts in Afghanistan (Operation Enduring Freedom; OEF) and Iraq (Operation Iraqi Freedom; OIF) have resulted in unprecedented rates of exposure to high-intensity blasts and resulting brain injury. Dennis (2009) reports that during 2005-2007, 68% of U.S. military personnel injured in the OEF/OIF conflicts had blast-related injuries and 28%-31% of those evacuated to Walter Reed Army Medical Center (WRAMC), Washington, DC had brain injuries. While the common focus of auditory evaluation is on damage to the peripheral auditory system, the prevalence of brain injury among those exposed to high-intensity blasts suggests that damage to the central auditory system is an equally important concern for the blast-exposed Veteran. Discussions with clinical audiologists and OEF/OIF Veterans Service Office personnel suggest that a common complaint voiced by blast-exposed Veterans is an inability to understand speech in noisy environments, even when peripheral hearing is within normal or near-normal limits (see attached letters of support). Such complaints are consistent with damage to neural networks responsible for higher-order auditory processing. This proposal is the second phase of a research project focused on examining the degree to which central auditory processing (CAP) dysfunction is a result of blast exposure. Over the initial period of funding, data collection at WRAMC and the VA RR&D National Center for Rehabilitative Auditory Research (NCRAR) established that CAP dysfunction is present in Warfighters exposed to high-intensity blasts while serving in combat. Recently blast-exposed patients with and without diagnoses of mild traumatic brain injury (mTBI) tested at WRAMC showed differences from controls tested at NCRAR on one or more behavioral and neurophysiological tests used to evaluate central auditory function. This project will 1) develop a more accurate estimate of the prevalence of central auditory
Sponsor: VA Office of Research and Development

Current Primary Outcome: Number of Blast-exposed Veterans With Abnormal Abilities in One or More Behavioral Tests of Central Auditory Processing [ Time Frame: six months ]

Tests to be administered:

Dichotic Digits Test: Percentage of digits reported correctly from 0 (worst performance) to 100 (best performance) Gaps in Noise Test: Approximate threshold in milliseconds from 2 (best) to 20 (worst) Staggered Spondaic Words Test: Total number of errors from 0 (best) to 40 (worst) Masking Level Differences Test: Difference in threshold between diotic and dichotic stimuli in decibels from 0 (worst) to 24 (best) Frequency Pattern Test: Percentage of sequences reported correctly from 0 (worst performance) to 100 (best performance) Adaptive Tests of Temporal Resolution: Not reported due to software error in stimulus presentation



Original Primary Outcome: Number of Blast-exposed Veterans With Abnormal Abilities in One or More Behavioral Tests of Central Auditory Processing [ Time Frame: six months ]

Tests to be administered:

  • Dichotic Digits Test
  • Gaps in Noise Test
  • Staggered Spondaic Words Test
  • Masking Level Differences Test
  • Frequency Pattern Test
  • Adaptive Tests of Temporal Resolution


Current Secondary Outcome:

  • Number of Participants With Abnormal Ratings of Self-reported Ability to Process Auditory Information in Various Settings [ Time Frame: six months ]

    Questionnaires to be administered:

    Hearing Health Inventory Speech, Spatial, and Qualities of Hearing

  • Comprehensive Audiological Examination [ Time Frame: six months ]
  • Functional Hearing Ability in Multitalker Environments [ Time Frame: six months ]
  • Number of Participants With Decreased Amplitudes or Increased Latencies in Electrophysiological Tests of Central Auditory Function [ Time Frame: six months ]

    Tests to be administered:

    Auditory Brainstem Response Long Latency Response



Original Secondary Outcome:

  • Number of paricipants with abnormal ratings of self-reported ability to process auditory information in various settings [ Time Frame: six months ]

    Questionnaires to be administered:

    • Hearing Health Inventory
    • Speech, Spatial, and Qualities of Hearing
  • Comprehensive Audiological Examination [ Time Frame: six months ]
  • Functional hearing ability in multi-talker environments [ Time Frame: six months ]
  • Number of Participants With Decreased Amplitudes or Increased Latencies in Electrophysiological Tests of Central Auditory Function [ Time Frame: six months ]

    Tests to be administered:

    • Auditory Brainstem Response
    • Long Latency Response


Information By: VA Office of Research and Development

Dates:
Date Received: March 2, 2012
Date Started: May 2012
Date Completion:
Last Updated: December 15, 2016
Last Verified: December 2016