Abstract: Aim of the study: This study was carried out to assess the effects of high blood pressure and its associated
changes in the form of high fibrinogen level and high plasma atrial natriuretic peptide (ANP) level on hearing
threshold in hypertensive patients. In this study, 100 persons (200 ears) 50 males and 50 females, with age range of
50-55 years, took part. They were equally divided into two groups, hypertension group and control group.
Hypertension group included hypertensive patients previously diagnosed as hypertensive patients of at least 10 years
duration with systolic BP above 140 mmHg and diastolic BP above 90 mmHg. They were under treatment of
hypertension. After audiometry, the hypertension group was divided into two subgroups according to hearing
threshold, the first subgroup contained hypertensive patients with hearing threshold less than 25 dB(with no hearing
loss) and the second subgroup contained hypertensive patients with hearing threshold above 25 dB(affected with
hearing loss). Control group contained normtensive persons with systolic blood pressure and diastolic blood pressure
less than 140 mmHg and 90 mmHg respectively. Blood pressure (Systolic, diastolic and mean), pure tone audiometry
at different frequencies, plasma fibrinogen level, and plasma ANP level, were measured. Results:- The results
indicated that: 1- There is highly significant (p<0.001) increase in hearing thresholds (worse hearing) at all high
frequencies in hypertensive patients. The highest hearing threshold was recorded at 8000 Hz-frequency.2- There is
an increase in percentage ratio of persons affected with hearing impairment at 2000, 4000 and 8000 Hz frequency
separately (hearing threshold above 25 dB) in hypertensive patients on comparison with control group. The highest
percentage ratio of persons with hearing deterioration at certain frequency is at 8000 Hz–frequency. It may be an
indicator of beginning of hearing impairment in hypertensive patients. 3- There is an increase in percentage ratio of
persons affected with high-frequency hearing impairment (mean hearing threshold in all high frequencies collectively
in the same person above 25 dB) associated with high blood pressure It arrived to 84% in hypertensive patients
instead of 22% in controls. High blood pressure leads to increase in number of affected persons with highfrequencies
hearing impairment to about 4 times as in controls. 4- High blood pressure is associated with highly
significant (p <0.001) high fibrinogen level. That level is positively correlated with hearing threshold at all high
frequencies, and positively correlated with hearing threshold separately at 8000 Hz-frequency.5- High blood pressure
is associated also with highly significant (p <0.001) elevated plasma ANP level. ANP level is positively correlated
with, mean blood pressure, hearing threshold at all high frequencies, and at hearing threshold of 8000 Hz-frequency.
6- In hypertensive patients who affected with high frequency hearing loss, there is significant (p < 0.05) increase of
plasma fibrinogen level and plasma ANP level compared with hypertensive patients without hearing loss.
Conclusion: High blood pressure is a risk factor for high-frequency hearing impairment. Hypertension is also
associated with increase percentage ratio of persons affected with high-frequency hearing impairment. 8000 Hzfrequency
is the most affected frequency in hypertensive persons, and may be an indicator for start of hearing
impairment in them. High plasma fibrinogen level and high plasma ANP level, that are associated with high blood
pressure, are directly related to deterioration of hearing threshold in hypertensive patients. The role of fibrinogen and
ANP in pathogenesis of hearing loss in hypertensive patients must be thoroughly investigated. Also extended high
frequency audiometry is highly recommended for early detection of hearing loss in hypertensive patients.
[Nawal B. Ali; Mohamed Abd Elgfar and Eman A Thabet. Effects of High Blood Pressure on Hearing Threshold
at Different Frequencies and Its Mechanisms in Hypertensive Patients. J Am Sci 2012;8(12):618-629].