Delayed auditory brainstem responses in diabetes mellitus

Abstract

S U M M A R Y Diabetic patients have longer interpeak latencies in the brainstem auditory evoked responses than age-matched controls. The delay is not related to clinical hearing loss or blood glucose level at time of testing. Since waves I and II are normal in latency, the conduction velocity of the eighth nerve is not involved. The delay occurs between waves II and V, which would reflect altered transmission times in auditory brainstem and midbrain structures, and suggests the presence of a central neuropathy in patients with diabetes.It is well known that diabetic patients develop peripheral and autonomic neuropathy. Recent reviewsl'3 have suggested that they may also suffer from central neuropathy, or degeneration of the higher nervous system; De Jong4 has pointed to clinical and pathological evidence that the brain parenchyma might be affected. Kent5 has argued that diabetic patients show some neurological and psychological symptoms that might signify premature aging. However, physiological evidence of central nervous system dysfunction has not been forthcoming, and relatively little attention has been paid to the possibility of central neuropathy in such patients.In a pilot study6 7 we compared the auditory cortical evoked responses of a group of diabetics with those of an age-matched control group, and found the diabetics to have greater suppression of the cortical auditory evoked response at high rates of stimulation, implying a slowing of the recovery process in the central nervous system. The interpretation of these changes was not clear; similar modifications of the auditory evoked response could occur in clinical hearing loss, which has been reported in diabetics.8-'2 Hypoglycaemia,

Speech-Evoked Auditory Brainstem Response in Individuals with Diabetes Mellitus Type 2

“…These findings may justify the abnormal neural transmission delay at the brainstem level. The finding of this earlier study has been supported by subsequent ABR investigations in diabetes mellitus [5,6,13,14] . Even though some of the authors suggested a dual pathological mechanism, including silent infarct and metabolic disturbances as the explanations of these findings, [14] he delayed onset response to speech stimulus revealed by the current study can also be attributed to these pathological changes in the auditory brainstem.…”

“…The /da/ stimulus contains a broader frequency range; hence, it elicits a huge negative-going peak termed as wave A [16,17] . Previous investigations using the click-evoked ABR suggests clear evidence of prolonged latencies of wave V in diabetes mellitus [5,13] .…”

“…In the earliest ABR investigations in diabetic individuals, Donald et al [13] found significant prolongation of wave III and V in spite of normal latencies of wave I and II [13] . This finding suggests that, even though the eighth nerve transmission is normal, the delay in wave III and V correlates to the transmission delay at the inferior collicular level, probably from the brainstem to midbrain.…”

“…However, most of the previous studies explored the relationship between diabetes and hearing impairment using click-evoked auditory brainstem response only [6,7] . In these studies, the inter-peak latencies I-III, III-V, and I-V have been significantly found to be delayed [5,[12][13][14] . Even though the click-evoked ABR is the gold standard for assessing neural encoding of acoustic stimuli at the brainstem level, it does not account for behaviorally relevant complex signal processing, such as speech [15] .…”

Evaluation of brainstem auditory evoked potential in type 2 diabetes mellitus individuals

“…[12][13][14][15][16][17][18] Report from American Clinical Society also stated that sensory neural hearing loss is more common among DM than non DM subjects. In present study, on observing, we found that the latencies of the cases and controls were decreased when compared with the normal values as illustrated by Chippa et al, but on comparing the latencies between the cases and controls, there was a highly significant increase in the latencies of the cases.…”