The impact of severity of hypertension on auditory brainstem responses

Abstract

Background: Auditory brainstem response is an objective electrophysiological method for assessing the auditory pathways from the auditory nerve to the brainstem. The aim of this study was to correlate and to assess the degree of involvement of peripheral and central regions of brainstem auditory pathways with increasing severity of hypertension, among the patients of essential hypertension. Method: This study was conducted on 50 healthy age and sex matched controls (Group I) and 50 hypertensive patients (Group II). Later group was further subdivided into-Group IIa (Grade 1 hypertension), Group IIb (Grade 2 hypertension), and Group IIc (Grade 3 hypertension), as per WHO guidelines. These responses/ potentials were recorded by using electroencephalogram electrodes on a root-mean-square electromyography, EP MARC II (PC-based) machine and data were statistically compared between the various groups by way of one-way ANOVA. The parameters used for analysis were the absolute latencies of Waves I through V, interpeak latencies (IPLs) and amplitude ratio of Wave V/I. Result: The absolute latency of Wave I was observed to be signifi cantly increased in Group IIa and IIb hypertensives, while Wave V absolute latency was highly signifi cantly prolonged among Group IIb and IIc, as compared to that of normal control group. All the hypertensives, that is, Group IIa, IIb, and IIc patients were found to have highly signifi cant prolonged III-V IPL as compared to that of normal healthy controls. Further, intergroup comparison among hypertensive patients revealed a signifi cant prolongation of Wave V absolute latency and III-V IPL in Group IIb and IIc patients as compared to Group IIa patients. These fi ndings suggest a sensory defi cit along with synaptic delays, across the auditory pathways in all the hypertensives, the defi cit being more markedly affecting the auditory processing time at pons to midbrain (IPL III-V) region of auditory pathways among Grade 2 and 3 hypertensives. Conclusion: Hence, we conclude there has been greater involvement of pontomesenchymal region with the increasing severity of the disease.

Effect of severity of hypertension on brain stem auditory evoked potentials

“…They added that the delay in auditory processing time may be considered as an index of subclinical expression of visceral damage in hypertensive patients. 8 Jyoti et al, also showed prolongation of all absolute latencies of BAEP waves I and V in hypertensive group and strongly reported that the changes in hypertensive patients, can be due to multiple factors that include associated dyslipidemia, oxidative stress or arteriosclerosis leading to poor blood supply to different organs. 12 Haldwani et al, in their study found the relation between mean arterial pressure and BAEP latencies in hypertensive patients and they added that it provided an electrophysiological evidence of interaction of BP control mechanism in the brainstem with auditory pathway.…”

“…Some found a relationship between hearing loss and hypertension but some not. [6][7][8] In this study we tried to find the effects of hypertension on BAEP and whether the increasing severity of hypertension also affects the amplitude and latency of…”

Brainstem Auditory Evoked Potential Responses in Primary Hypersensitive Patients and Its Correlation With Mean Arterial Blood Pressure

“…[5,6,7] Prolonged interpeak latencies have also been noticed in benign intracranial hypertensive patients and authors proposed stetchingcompression of cochlear nerve as a mechanism for this. [10] As far as correlation of waves of BAEPs with BP is concerned conflicting data is available.…”

“…Some have found a relationship between hypertension and hearing loss while some have not. [5], [6], [7] Results have been unclear, and there is the need for further studies as far as peripheral and central hearing are concerned in the affected population One of the studies has reported a correlation of peak latencies and interpeak latencies of waves of BAEPs with systolic and diastolic blood pressure [5] but data is still lacking, and its correlation with mean blood pressure has not been studied.…”

Study of brainstem auditory evoked potentials in early (grade I) essential hypertensive patients

“…8 These central neuronal damage may alter electrical activity in the central nervous system and may affect various evoked potentials. 9 Evoked potentials are responses to stimulation of a sensory pathway in the nervous system. This comprise of stimulation of a sensory nerve in the limb (somatosensory evoked potentials-SSEPs), the visual system (visual evoked potentials-VEP) or the auditory system (brain stem auditory evoked potentials-BAEP or brain stem auditory evoked responses-BAER).…”