An evaluation of hearing and balance functions in adults with iron deficiency

Iron deficiency without anemia means decreased iron stores that precede iron deficiency anemia or persist without progression. Iron deficiency anemia is a more serious condition that develops with the presence of microcytic hypochromic erythrocytes and low iron level is associated with anemia. Since the internal auditory artery, which provides blood supply to the cochlea and vestibular labyrinth, is an end artery with minimal collaterals, the inner ear requires high-energy metabolism and some cochlear enzymes contain iron, hypoxia due to iron deficiency may affect the hearing and vestibular system. In this study, it was aimed to evaluate hearing and balance functions in adults with iron deficiency. 19-50 years old, 22 individuals diagnosed with iron deficiency anemia and 22 individuals iron deficiency without anemia and 22 healthy individuals were included. All individuals participating in the study were evaluated with pure tone audiometry (125-16000 Hz), videonystagmography, ocular vestibular evoked myogenic potentials (oVEMP), cervical vestibular evoked myogenic potentials (cVEMP), video head impulse test (vHIT) and subjectively before the audio-vestibular tests were performed it was questioned whether there were any complaints. Tinnitus was observed at a rate of 27.3% in iron deficiency without anemia group and 36.4% in the iron deficiency anemia group, the difference is statistically significant (p<0.05). Hearing thresholds of the iron deficiency anemia group were found to be significantly higher than the control group at 125-14000Hz frequencies (p<0.016). Pure tone average value in the iron deficiency groups was found to be statistically significantly higher than the control group (p<0.016). The incidence of sensorineural hearing loss was 9.1% in the right ear, 27.3% in the left ear in the iron deficiency without anemia group, and 27.3% in the iron deficiency anemia group, in the right and left ears. While the Pursuit test was found to be pathological in 9 patients (40.9%) in the iron deficiency anemia group, it was normal in the iron deficiency anemia and control groups, there was a statistically significant difference between the groups (p<0.05). In the iron deficiency anemia group, 13.6% in oVEMP and 9.1% in cVEMP did not respond (p<0.05). In the oVEMP test, the P1 latency value in the iron deficiency anemia group and the iron deficiency without anemia group, the N1 latency and N1-P1 interlatency values in the iron deficiency anemia group were significantly longer than the control group (p<0,016). N1-P1 amplitude values in oVEMP and cVEMP tests were lower in the iron deficiency anemia group than in the control group (p<0.016). The mean value of anterior SCC VOR gain was statistically lower in iron deficiency groups than in the control group (p<0.016). The mean values of anterior SCC VOR gain were 0.79 ± 0.2 in the iron deficiency anemia group; 0.81 ± 0.16 in the iron deficiency without anemia group. In the iron deficiency anemia group, 4.5% had covert, 9.1% overt and 6.8% covert-overt saccades; 6.8% overt saccades were observed in the iron deficiency without anemia group, the difference between the groups was significant (p<0.05). In line with the findings obtained from our study, it was concluded that the auditory and vestibular system may be affected due to hypoxia due to iron deficiency.