Venturi hypothesized, based on his comparisons of monaural and binaural listening, that the relative intensities at the two ears (the “interaural level difference” ILD), give rise to the ability to localize sounds in space. The work of Venturi (1796) was described by Wade and Deutsch (2008) and Stecker and Gallun (2012). The importance of studying abnormal auditory function has been known from the very first studies of binaural hearing. The final section will address the many opportunities for additional studies that are made clear by what this review is and is not able to tell us about the mechanisms of binaural impairment and about the abilities of various patient groups to make use of the auditory spatial cues available in the environment.īinaural function has been studied clinically from as far back as 1876 ( Pierce, 1901). The second will turn to those patients with central dysfunction, for whom detection of pure tones is often normal or near normal but for whom binaural sensitivity has been shown to be impaired. The first will focus on patients with conductive hearing loss (CHL) and sensorineural hearing loss (SNHL). This review of the patient literature will be divided into two main sections. After surveying a variety of methods of characterizing binaural impairment, the literature on patient groups will be selectively reviewed. This review of binaural impairment in adult human listeners will start with an overview of the history of the area and the current model of the binaural system. Consequently, dysfunction of the binaural system can reduce the ability to navigate the auditory scene ( Gallun and Best, 2020).

Binaural hearing has obvious defensive and predatory advantages, as well as serving an important communicative function. The ability to process the information available in pressure waves arriving at the two ears (“binaural hearing”) is available to living creatures ranging from insects ( Hedwig and Stumpner, 2016) to humans (for review see Stecker and Gallun, 2012).

Future work in this area has the potential to bring awareness of binaural dysfunction to patients and clinicians as well as a deeper understanding of the mechanisms of binaural hearing, but it will require the integration of clinical research with animal and computational modeling approaches. The literature reviewed makes clear that while each of these conditions has the potential to impair the binaural system, the specific abilities of a given patient cannot be known without performing multiple behavioral and/or neurophysiological measurements of binaural sensitivity. This review focuses on a number of studies that are fundamental to understanding what is known about the effects of peripheral hearing loss, aging, traumatic brain injury, strokes, brain tumors, and multiple sclerosis (MS) on binaural function. Despite over 100 years of study, there are still many fundamental questions about binaural hearing that remain unanswered, including how impairments of binaural function are related to the mechanisms of binaural hearing.

Binaural hearing loss diagnostic codes