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| ORIGINAL ARTICLE |
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| Year : 2017 | Volume
: 19
| Issue : 1 | Page : 1-5 |
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Do blind people have better hearing levels than normal population?
Abdul-Rahman Ali Al-Saif1, Kamal-Eldin Ahmed Abou-Elhamd2, AbdulRahman Khalid Alabdalali1, Sayed Ibrahim Ali3
1 Medical Student, College of Medicine King Faisal University, Al-Ahsa, Saudi Arabia
2 Professor of ENT, College of Medicine, King Faisal University, Al-Ahsa, Saudi Arabia
3 Assistant Professor of Statistics, College of Medicine King Faisal University, Al-Ahsa, Saudi Arabia
| Date of Web Publication | 7-Jan-2020 |
Correspondence Address:
Kamal-Eldin Ahmed Abou-Elhamd
College of Medicine King Faisal University P.O. Box 400 Al-Ahsa 31982
Saudi Arabia
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/1319-8491.275306
Objective: To find out if there is a difference in hearing levels between normal and blind people. To answer the following questions, “Is the concept of losing one sense will improve the other senses right or wrong? If someone born blind, will he have better hearing abilities than those with a good vision?”
Study Design: A cross sectional study.
Materials and Methods: Forty male students aged between 13-22 years old from two special education schools were randomly selected to evaluate their hearing levels from Eastern district, Saudi Arabia at the period from February 2016 to April 2016. They were divided into two groups. The first group included the student with visual impairment (13 students) and total blindness (7 students) for more than 5 years. The second control group is of 20 students with normal vision. A questionnaire was answered by each one. Anyone with history of ear disease was excluded from the study. A pure tone average thresholds (PTAs) were obtained for left and right ears for the frequencies 0.125, 0.25, 0.5, 1, 2, 4 and 8 kHz. Data were statistically evaluated using SPSS version 20.
Results: Hearing levels were normal in most of the participants with mild hearing low average for both ears in the visually impaired plus totally blind subjects compared to the control group was non-significant, P value = 0.829 (>0.05). While, there was significant difference at the hearing levels between pure tone average for both ears in the three groups (visually impaired, totally blind and normally sighted group) using ANOVA test, P value = 0.04 (< 0.05) with the lowest hearing level at the totally blind group.
Conclusion: Loss of one sense does not potentiate other senses as some people believe. Blind people have the same level of hearing as normal population.
Keywords: hearing level; blindness; visual impairment; Saudi Arabia
How to cite this article:
Al-Saif ARA, Abou-Elhamd KEA, Alabdalali AK, Ali SI. Do blind people have better hearing levels than normal population?. Saudi J Otorhinolaryngol Head Neck Surg 2017;19:1-5 |
How to cite this URL:
Al-Saif ARA, Abou-Elhamd KEA, Alabdalali AK, Ali SI. Do blind people have better hearing levels than normal population?. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2017 [cited 2023 Jan 30];19:1-5. Available from: https://www.sjohns.org/text.asp?2017/19/1/1/275306 |
| Introduction | |  |
Communication and people interactions in our daily life activities depend on hearing and vision [1]. Most blind people were not born blind, they become blind. This means that, having learned to rely on their sight in order to recognize and relate to the world, they must now radically revise their basic assumptions about that world [2],[3].
It is reported that 285 million people are estimated to be visually impaired worldwide. Thirty nine million are blind and 246 million have low vision [4]. In Kingdom of Saudi Arabia (KSA) there was study conducted on 14,577 people representing the settled population of KSA. The survey revealed that 1.5% of the population are blind and another 7.8% are visually impaired according to the World Health Organization definition [5].
Hearing is one of the important senses by which we can understand & communicate with surroundings. Hearing thresholds of 25 dB or bigger in any ear is said to have hearing loss (HL). HL may be mild, moderate, severe or profound. It is reported as well that about 360 million people worldwide have disabling hearing loss [6].
Loss of one sense will affect other senses. Music experts often cite blind musicians Stevie Wonder and Ray Charles as examples of how a lack of sight can heighten or enhance hearing. Therefore loss of vision can result in changes in auditory perceptual abilities and in the way sounds are processed within the brain [7]. A number of studies have reported that people who become blind at an early age can hear notes and localize sounds more precisely than those with sight or people who go blind later in life [7]. In a same conception, a recent review on visual abilities in the profoundly deaf suggests that enhanced visual performance in those group [8],[9]. King in 2015 reported that blind persons are dependent on their hearing as they develop superior auditory skills, either as a result of plasticity within the auditory system or through the recruitment of functionally relevant occipital cortical areas that lack their normal visual inputs [7]. Improvements in hearing abilities following blindness may result from an increase in cortical territory devoted to auditory processing [10].
To find out if there is a difference in hearing levels between normal and blind people. To answer the following questions, “Is the concept of losing one sense will improve the other senses right or wrong? If someone born blind, will he have better hearing abilities than those with a good vision?”
| Material and Methods | | |
The study was conducted with the help of the hearing and speech department in the special education center, Khalid bin Al-Walid middle school, and Al-Mubarraz high school, Eastern district, Saudi Arabia from February 2016 to April 2016. Forty male students aged between 13-22 years old from both schools were randomly selected to participate. The participants were divided into two groups, each group consisted of 20 students based on the visual acuity. The first group included the student with visual impairment (13 students) and total blindness (7 students) for more than 5 years. The second group had 20 students with normal vision, constituting the control group. An informed verbal consent for their participation in the study was obtained at the beginning with explanation of what the research is about to all the participants. A questionnaire was answered by each one of them about their history [Figure 1], It includes the history of chronic diseases, ear problems, the use of hearing aids, family history of ear problems, the use ototoxic drugs and past history of ear surgery. Anyone with history of ear disease was excluded from the study. A pure tone average thresholds (PTAs) were obtained for left and right ears for the frequencies 0.125, 0.25, 0.5, 1, 2, 4, and 8 kHz. Data were statistically evaluated using SPSS version 20.
| Results | | |
Our study included 40 participants. They all replied the questionnaire and the findings are shown in [Figure 2].
They were visually impaired subjects (13=32.5%), totally blind persons (7=17.5%) normally sighted controls (20=50%). The average age of the visually impaired group was 16 ± 2.1 years, the totally blind group was 16.6 ± 2.8 years, and the normally sighted group was 15.2 ± 1.5 years [Table 1]. All the 40 participants were Saudi males.
Hearing levels were normal in most of the participants with mild hearing loss in 4 ears of 3 participants (5%) [Table 2].
Pure tone average ranges from 5 to 23 dB for the visual impairment group (mean 14.9 dB), 10 to 36 dB for the total blindness group (mean = 20.8 dB), and 11to 33 dB for the Using independent sample T-test SPSS version 20, there was non-significant difference at the hearing levels between pure tone average for both ears in the visually impaired plus totally blind subjects with the control group, P value = 0.829 (> 0.05) [Table 3]. normal sighted group (mean = 16.6 dB).
While, there was significant difference at the hearing levels between pure tone average for both ears in the three groups (visually impaired, totally blind and normally sighted group) using ANOVA test, P value = 0.04 (< 0.05) with the lowest hearing level at the totally blind group [Table 4].
| Discussion | | |
This study was planned based upon the hypothesis that sensory deprivation (e.g. blindness) may has some effect on the intact senses. Blind people depend more on their intact sensory modalities (e.g. hearing), making them sharper and perform better compared to normal performance in order to compensate the lack of visual inputs [6].
Our study showed that the mean pure tone average for both visually impaired and totally blind to be 14.9 dB and 20.8 dB respectively compared to 16.6 dB in normally sighted people. Which means that totally blind participants have significantly worse hearing abilities than sighted age matched controls, and that against our conception [11]. Participants with visual impairment didn’t show significant difference from the sighted age matched controls, and that could be due to having some residual visual abilities.
Most of the previous studies which were similar to our study focused on the ability of a blind person to localize sounds in comparison with normally sighted person. Nilsson & Schenkman reported that due to sound being the only source of information used for sound localization for a long term, the blind has greater inter- aural time differences sensitivity and inter-aural level differences sensitivity compared to sight age-matched [12]. Another study by Kolarik et al. focused on the distance discrimination, suggesting that totally blind people have better sound distance discrimination than sight age-matched and no difference when comparing people with partial visual loss to sight age-matched [11].
Limitations
Our study cannot be generalized to all the blind, since it was done only for a small number of blind people in a very limited area.
| Conclusion | | |
Loss of one sense does not potentiate other senses as some people believe. Blind people have the same level of hearing as normal population.
| References | | |
| 1. | Vreeken HL, van Rens G, Knol DL, van Reijen NA, Kramer SE, Joost M Festen JM, and van Nispen R. Dual sensory loss: A major age-related increase of comorbid hearing loss and hearing aid ownership in visually impaired adults. Geriatr Gerontol In. 2014; 14: 570-576.  |
| 2. | Fitzgerald RG, Parkes CM. Blindness and loss of other sensory and cognitive functions. BMJ, 1998;316 (7138): 1160-1163. |
| 3. | Fitzgerald RG. Reactions to blindness: an exploratory study in adults with recent loss of sight. Arch Gen Psychiat. 1970; 22:370-379. |
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| 5. | Tabbara KF, Ross-Degnan D. Blindness in Saudi Arabia. JAMA. 1986; 255(24):3378-3384. |
| 6. | |
| 7. | King AJ. Crossmodal plasticity and hearing capabilities following blindness. Cell Tissue Res. 2015; 361:295-300. |
| 8. | Bottaria D, Turattoa M, Bonfiolic F, Abbadessac C, Selmic S, Beltramec MA, Pavania F. Change blindness in profoundly deaf individuals and cochlear implant recipients. Brain Res. 2008;1242: 209-218. |
| 9. | Bavelier D, Brozinsky C, Tomman A, Mitchell T, Neville H, Liu G. Impact of early deafness and early exposure to sign language on the cerebral organization for motion processing. J Neurosci. 2001;21(22):8931-42. |
| 10. | Lazzouni L, Lepore F. Compensatory plasticity: time matters. Front Hum Neurosci. 2014; 8:340. |
| 11. | Kolarik AJ, Cirstea S, Pardhan S. Evidence for enhanced discrimination of virtual auditory distance among blind listeners using level and direct-to-reverberant cues. Exp Brain Res. 2013; 224:623-633. |
| 12. | Nilsson ME, Schenkman BN. Blind people are more sensitive than sighted people to binaural sound-location cues, particularly inter-aural level differences. Hearing Res. 2016; 332: 223-232. |
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]
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