Effect of Rh- Positive Blood Group on Distortion Product Otoacoustic Emission Input–Output Function

Abstract

The blood group system of human beings can impact the health and auditory system. There are correlations between various audiological test findings and blood groups. Studies have shown that persons with the O blood group have reduced resonance frequency of the middle ear and amplitude of otoacoustic emissions. Therefore, Otoacoustic emissions (OAE) results could be different across blood groups. The current study aimed to determine the difference in Distortion product otoacoustic emission input–output function in persons with varying groups of blood. A total of sixty college-going young female adults, aged between 18 and 25 years, participated in the current study. They were divided into four groups, each with 15 participants based on the blood group type (A, B. AB. O). The subjects underwent Distortion product otoacoustic emission (DPOAE) input–output function on the following frequencies: 703 Hz,1060 Hz,1416 Hz,2114 Hz,2827 Hz,4243 Hz, and 5645 Hz. The analysis showed no significant difference in the area and slope of the Distortion product otoacoustic emission input–output function at all frequencies. Thus, the study’s result shows no effect of the blood group on Distortion product otoacoustic emission input- output function.

Introduction

The blood group system of human beings can impact the health and auditory system. There are majorly 8 types of blood groups (A + , A−, B + , B−, O + , O−, AB + , AB−) [1]. There are correlations between various audiological test findings and blood groups. Earlier studies have shown that people with the O blood group had increased susceptibility to noise-induced hearing loss [2]. Several biological differences in the blood group system could be a risk factor for the susceptibility of developing certain diseases, such as gastric cancer in A blood group individuals and peptic ulcer in O blood group individuals [3].

It has been noted that the risk of acquiring noise-induced hearing loss is higher in industrial workers with blood group O than in other blood groups [4]. Following previous studies, military personnel with the O blood group exposed to loud noise are reported to be more vulnerable to noise-induced hearing loss than non-O blood group individuals [5].

Studies have reported differences across blood groups by administering various audiological tests. Recent literature has investigated the effect of blood groups on acoustic reflex thresholds and tympanometric findings. Results showed elevated thresholds in acoustic reflex and resonance frequency in persons with the O blood group than others [6]. It is also reported that reduction in the Distortion product otoacoustic emissions amplitude in people with blood group O compared to non-O blood groups [2]. Similar findings also reported that individuals with the O blood group are more vulnerable to cochlear damage leading to noise-induced hearing loss [1].

Studies show no significant difference in auditory thresholds of ultra-high frequency and reduced ultrahigh-frequency Oto acoustic emissions in individuals with the O blood group [7]. Studies have reported the association between blood groups and Auditory Brainstem Response (ABR). The changes were attributed to the physiology, specifically reduced cochlear microphonics in individuals with O-type blood group [8]. Various audiological tests reveal the effect of blood groups on cochlear functions in different age groups [1, 2, 6–8].

A recent study has been done to examine the characteristics of Oto-acoustic emission of other blood groups in full-term neonates. The results showed that participants in the O blood group have low Otoacoustic emissions values compared to the A, B, and AB blood groups. This study has highlighted the need for more research to correlate the blood groups and the cochlear functions, specifically to find the influences of noise on outer hair cell damage [9].

Studies also explored the relationship between blood group and cochlear function in 463 persons with normal hearing. They indicated no significant differences in Transient otoacoustic emissions/ Distortion product otoacoustic emissions measures in adults with different blood groups. It suggests that adults with the O blood group are not prone to cochlear dysfunction [10]. These findings are inconsistent with previous studies, which reported reduced Transient otoacoustic emissions/ Distortion product otoacoustic emissions amplitude and Signal to noise ratio (SNR) for adults with the O blood group. They hypothesized that this could be because of the relatively small sample size, which could have resulted in significant differences for persons with the O blood group compared to others [10].

Considering the earlier studies, Otoacoustic emissions findings could be different across blood groups. These findings suggest that normal non-linear cochlear mechanisms might be altered for persons with different blood groups. Distortion Product Otoacoustic Emission is an evoked OAE that depends on two stimuli at different frequencies and tone levels combined to give the input and output function of the cochlea, which the microphone can pick up. In addition, while measuring conventional DPOAE, the intensity levels of the primary tones f1 and f2 (i.e., L1 and L2 are kept constant; L1 = 65 dB SPL L2 = 55 dB SPL) across the frequencies. In the DPOAE Input Output function, the primary tones presentation levels vary for each frequency. DPOAE input output function are recorded with different intensities of input levels and the change in DPOAE amplitude with reduction in each intensities was noted at a fixed frequency The slope of the DPOAE I/O function also provides insight into the cochlea’s status in terms of its functioning.

The previous studies showed that the amplitude of OAE is reduced for blood group O. In addition, the reduction in the amplitude of OAE could be due to the reduced number of healthy Outer hair cells (OHCs) present for blood group O [1, 2, 6, 7]. DPOAE I/O is the measure of change in OAE amplitude at different intensities. Hence, if the reduction occurs at one intensity, proportional reduction may also have occurred at subsequent intensities for adults with the O blood group. However, scarce literature has attempted to measure the DPOAE input–output function in persons with different blood groups.

Hence the present study aimed to study the differences in the input–output (I/O) function of Distortion Product Oto Acoustic Emission (DPOAE) across blood groups (AB positive, A positive, B positive, O positive). The Objectives are.

• To measure the following parameters of DPOAE (I/O) function for individuals with different blood groups (A + ve, AB + ve, B + ve, O + ve).

  1. Slope of DPOAE input output function.
  2. Area under the curve of DPOAE input output.

Method

Participants

Sixty female participants of age ranging from 18 to 25 years (mean age: 19.3.5; standard deviation [SD]: 5.5) with ABO blood group were recruited for this study based on a non-random convenient sampling method. Participants were aware of their own blood groups. Accurate knowledge of blood group details was retrieved from the participant’s serological test report, which was administered during their academic year. The inclusion criteria included participants with no hearing loss or other otological issues such as ear pain, discharge, or impacted ear wax. Participants under any ototoxic drugs, exposed to loud sounds, and with a family history of hearing loss were excluded from the study.As the above-mentioned conditions could affect the outcomes of the present study. All the participants had positive rhesus factors (Rh). Only female participants were recruited in the study because the amplitude of the DPOAEs is reported to vary across gender [11]. They were subdivided into four groups based on the ABO blood group system (A + ve, B + ve, O + ve, AB + ve). In each blood group, 15 participants were included.

Procedure

Screening Procedures

Each participant was screened for normal hearing using a standard diagnostic test battery, including pure tone audiometry, immittance audiometry, and transient evoked otoacoustic emissions (TEOAE). Pure tone audiometry was administered using a calibrated clinical audiometer “Inventis Piano” (Inventis Padova, Italy). In addition, Tympanometry was carried out to rule out the middle ear pathology in both ears using a calibrated middle ear analyzer (“Inventis Clarinet” (Inventis Padova, Italy). Furthermore, Transient evoked otoacoustic emissions was also carried out for the frequencies from 250 to 4000 Hz using a calibrated “Intelligent Hearing Systems Duet”(IHS, Miami, FL) instrument. An inclusion criterion for normal peripheral auditory system are as follows. All the participants had normal hearing sensitivity of pure tone thresholds (≤ 15 dBHL) at octave frequencies (250 Hz to 8000 Hz) for air conduction and from 250 to 4000 Hz for bone conduction using the “modified Hughson-Westlake procedure” in both ears [12]. In addition, all the participants had A-type tympanogram with acoustic reflexes present at 500 Hz to 2000 Hz which reveals normal middle ear functioning [13] and the presence of TEOAE, which reflects normal outer hair cells functioning in both ears, respectively [14–16]. All the Participants were met the inclusion criteria and underwent for further evaluation.

DPOAE Input Output Function

All participants underwent DPOAE input–output function in the Intelligent Hearing Systems Duet (IHS, Miami, FL) instrument. DPOAE input–output function was measured on the following frequencies: 703 Hz, 1060 Hz, 1416 Hz, 2114 Hz, 2827 Hz, 4243 Hz, 5645 Hz. DPOAE input output function was recorded from the intensity levels of 37 to 55 dB SPL in 5 dB steps with a ratio of f2/f1 at 1.22. The change in DPOAE amplitude with reduction in each intensities was noted at a fixed frequency. The emissions at each level plotted by the equipment were noted. The DPOAE input output function was recorded at each frequencies thrice. An average of three responses was taken for each response. A linear trend model was used to calculate the slope.The area under the curve was to be determined as the difference between the noise floor and the DP amplitude from 55 to 37 dB SPL [17]. The analyses were carried out using the square root of area² (i.e., area). The slope and area of DPOAE input output were calculated based on the method proposed by Gates et al. (2002) [18]. All the tests were conducted in an acoustically treated room. The permissible noise level of the room was as per ANSI/ASA S3.1–1999 standards [19].

Statistical Analyses

The statistical analysis of the data was done using the Statistical Package for Social Sciences (SPSS) version 21 (IBM Corp., Armonk, NY). The normal distribution of the data was analyzed using the “Shapiro–Wilk test of normality.

Ethical Consideration

All of the testing procedures were accomplished using a non-invasive technique in the current study and adhered to the conditions of the institutional ethical approval committee. The test procedures were clearly explained to the participants before testing.

Results

Sixty Participants were included in this study, with equal numbers in each ABO blood group. Blood group status for participants was provided through serological test report (n = 60).

DPOAE Input Output Function Slope and Blood Group Findings

A descriptive statistical analysis of the data was done to determine mean, and standard deviation (SD) for slope of the DPOAE input output function for the frequencies 703 Hz, 1060 Hz, 1416 Hz, 2114 Hz, 2827 Hz, 4243 Hz, 5645 Hz for different blood groups. The slope were similar between the blood groups.

Shapiro Wilk normality test showed that the data was not normally distributed, so non-parametric inferential statistics were carried out. Kruskal Wallis tests were done at each frequency for slope of the DPOAE I/O function. The results showed that there was no significant difference (p > 0.05) for the slope of DPOAE I/O function at all the frequencies across blood groups. The Mean and Standard Deviation of the slope of DPOAE I/O function for different frequencies across the four blood groups are shown in Fig. 1.

Fig. 1.

Mean and Standard Deviation of the slope of DPOAE I/O function for different frequencies across the four blood groups

DPOAE Input Output Function Area and Blood Group findings

A descriptive statistical analysis of the data was done to determine mean, and standard deviation (SD) for area of the DPOAE input output function for the frequencies 703 Hz, 1060 Hz, 1416 Hz, 2114 Hz, 2827 Hz, 4243 Hz, 5645 Hz for different blood groups. The area were similar between the blood groups.

Kruskal Wallis tests were done at each frequency for area of the DPOAE I/O function. The results showed that there was no significant difference (p > 0.05) for the area of DPOAE I/O function at all the frequencies across blood groups. The Mean and Standard Deviation of the area of DPOAE I/O function for different frequencies across the four blood groups are shown in Fig. 2.

Fig. 2.

Mean and Standard Deviation of the area of DPOAE I/O function for different frequencies across the four blood groups

Discussion

The present study attempted to find out the effect of blood groups on DPOAE input and output function. Although earlier studies have showed reduced amplitude and SNR of TEOAE/DPOAE measures in persons with O blood groups [1, 2, 6, 7]. The results of the current study showed that there was no significant difference for DPOAE slope and area across blood groups.

The results of the present study are agreeable to the previous study which also stated that there was no significant difference in slope of DPOAE I/O function at 4000 Hz and 6000 Hz in adults with different age and blood groups. In addition, no significant differences were found between the right and left ears in the slope of DPOAE I/O among blood groups [10]. They hypothesized these results could be because of the large sample size compared to previous studies’ sample sizes.

A study with large sample sizes can avoid type I and type II errors and reveal more valid results [10]. However, they did not studied lower and mid frequencies of the DPOAE input–output function. Thus, the current study used a low and mid-frequency region and reported the slope and area of the DPOAE I/O function. To our knowlwdge, this is one of the first findings on the effect of blood group on slope and area of DPOAE I/O function across frequencies.Thus, the present study concluded no changes in cochlear compressive non-linearity across blood groups.

Conclusions

The study evaluated the effect of DPOAE I/O across individuals with various blood groups with positive Rh factor. It was found that there was no significant difference in the area and slope of DPOAE I/O across different blood groups. Thus, the results show no effect of the blood group on DPOAE I/O function.

Limitations of the Study and Future Direction

The current study was carried out in a relatively smaller sample size with purposive sampling. The findings can be replicated with a large sample size using random sampling with different age groups in the future. The present study considered only female participants. Therefore, studies can be carried out in males and females, which would provide insights in detail. The study was conducted in Rh + ve adults and it would be interesting to see the effects of Rh—ve blood group on DPOAE input output function.

Authors’ Contributions

Bhuvaneswari Kumaar, Kamalakannan Karupaiah* Celcia Iruthayam and Meghana Sabu was involved in Study design, acquisition of data, drafting the manuscript, interpretation of the results; Sundaresan Ramachandran was involved in Supervision, interpretation of the results, drafting the manuscript, critical revision of the manuscript; Prashanth Prabhu was involved in Study design, supervision, critical revision of the manuscript and statistical analysis.

Funding

There is no funding by any agency for the manuscript.

Declarations

Conflict of interest

The authors declare that they have no competing interests.

Ethical approval

In the current study, all of the testing procedures were accomplished using a non-invasive technique and adhered to the conditions of the institutional ethical approval committee. The institutional ethical approval committee approved the current study Holy Cross College Ethical Committee (HCC EC) Reference No: (HCC/ERB/EC/PB-05/2023–2024). The test procedures were clearly explained to the participants before testing.