On correlating otoacoustic emissions with blood glucose levels.

The long term objective of this research is to develop a new means for diabetic patients to painlessly and non-invasively monitor their blood glucose levels. We propose a novel method for noninvasive glucose monitoring based on measurement and analysis of otoacoustic emissions (OAEs). OAEs are low-intensity sounds generated by the cochlea in response to acoustic stimuli. Evoking and measuring OAEs is done using a tiny speaker and microphone that fit snugly inside the ear canal. The OAE response can be partially masked or reduced in amplitude by presenting competing acoustic stimuli contralaterally (opposite ear), ipsilaterally (same ear), or both. This masking effect is caused by activation of neural efferent pathways from the brain. Neural effects, including evoked responses such as auditory brainstem responses and axonal transmission latencies, are known to correlate with glucose. This suggests that masked OAEs may correlate with glucose since masking is a result of neural activity, and neural activity is affected by glucose levels. Prior to our research, no studies have investigated the correlation of masked OAEs with blood glucose. In this paper we present our preliminary findings, including experimental results that suggest a correlation with blood glucose levels.