Brain-stem auditory evoked responses in COPD patients

COPD is a multi-system disorder. It appears to be associated with the presence of systemic inflammatory markers as C reactive protein. The present study aimed to evaluate the brain-stem auditory evoked potentials (BAEP) abnormalities in stable COPD patient and its correlation with high sensitivity C reactive protein (hs-CRP) as a part of multi-system disorder. This case control study was carried out at Mansoura University Hospital Egypt from October 2009 to February 2010. The study comprised 40 stable COPD patients and 15 healthy controls with no risk that may lead to neuropathy. All the patients and controls were subjected to the following: I-Thorough history taking and clinical examination. II-Pulmonary function tests including: 1-Spirometry 2-Body plethsymography 3-Arterial blood gases analysis. III- Record of brain-stem auditory evoked potentials (BAEP) including: latencies of waves I, II, III, IV and V together with interpeak latencies (IPLs) of I–III, I–V and III–V and amplitudes of waves I–Ia and V–Va. IV–Measurement of serum high sensitivity C reactive protein (hs-CRP) by ELISA technique. V–Statistical analysis. The level of hs-CRP reactive protein in COPD was significantly elevated and correlated with spirometric, blood gases parameters and GOLD stage. The BAEP latencies of waves I, II, III, IV and V, together with interpeak latencies and amplitudes of waves I–Ia and V–Va measured on both ears were significantly different in COPD patients than controls. The prevalence of brain-stem auditory evoked potentials abnormalities was higher among very severe group of COPD. Most of BAEP wave latencies together with interpeak latencies and wave amplitudes on both ears were significantly correlated with the spirometric and blood gases parameters. The level of hs-CRP was correlated significantly with abnormalities of BAEP variables. This study showed significant subclinical BAEP abnormalities in studied stable COPD male patients. This indicates conductive defect of auditory nerve, cochlea and even hearing pathway in the brain as a part of systemic inflammation. Theses BAEP abnormalities were significantly correlated with GOLD classification, hs-CRP and PaO2.