The effects of chronic hypoxemia on central auditory processing in patients with chronic obstructive pulmonary...

This study was designed to discover if chronic hypoxemia produced measurable deficits in subjects' ability to process complex auditory stimuli. In Part I, a group of normal middle-aged subjects and a group of middle-aged subjects with hypoxemia secondary to chronic obstructive pulmonary disease (COPD) were compared with respect to their performance on a central auditory test battery. (The test battery included the Staggered Spondaic Word, Synthetic Sentence Identification with Ipsilateral Competing Message, Synthetic Sentence Identification with Contralateral Competing Message, Memory for Unrelated Words, Memory for Sentences, and a Competing Sentence-Binaural Separation Test). The COPD group's scores were significantly poorer than the normal group's on two of the six tests. The pattern of test scores suggested that chronic hypoxemia produced its principle deficiency at the brain stem level. Part II of this study examined the specific relationships between pulmonary function, arterial blood gas levels, and central auditory performance in this same group of COPD subjects. Statistical analyses revealed that subjects with better pulmonary function and higher arterial blood oxygen levels had better performance on tests of central auditory function.