Education is generally acknowledged as an instrument for fostering the worth and development of individual, for individual sake and for general development of the society. One of the main goals of Education in Nigeria is that every child shall have a right to equal educational opportunities, irrespective of any real or imagined disabilities, each according to his/her ability (FRN, 2004). To give concrete meaning to the idea of equalizing educational opportunities for all children, their physical, sensory, mental, psychological or emotional disabilities notwithstanding, provisions must be made for educational needs of the impaired, in terms of instructional media, methodology, learning environment, classroom management etc. Impairment is therefore not seen as sufficient impediment to attainment of academic aspiration and optional fulfillment of individuals.
Impairment is a medical term for anatomical loss of body function. As noted by Ipaye (1996), impairment is malfunction of a part of the body, resulting from an injury, disease, hazard in the environment or genetic factor. Hearing sensitivity is indicated by the quietest sound that an animal can detect called the hearing threshold. Hearing loss exists when an animal has diminished sensitivity to the sounds normally heard by its species. In humans, the term hearing impairment is usually reserved for people who have relative insensitivity to sound in the speech frequencies.
There are two types of hearing impairments, conductive hearing impairment and sensorineural hearing impairment. A third type is a combination of the two called mixed hearing loss. Hearing impairment are categorized by their type-conductive, sensorineural or both by their severity, and by the age of onset. Furthermore, a hearing impairment may exist in one ear (unilateral) or in both ears (bilateral). A conductive hearing impairment is present when the sound is not reaching the inner ear, the cochlea. This can be due to external ear canal malformation, dysfunction of the eardrum or malfunction of the bones of the middle ear.
A sensorineural hearing loss is one resulting from dysfunction of the inner ear, the cochlea, commonly caused by damage to the hair cells in the cochlea. As noted by Lang and Meath-Lang (1995), in the language class, children with auditory perception problems may not perceive the difference between various consonant blend in English Language or be able to differentiate between the iron doorbell and the first ring of the telephone. Effective teaching of pupils who are deaf or hearing-impaired requires special skills and technologies. Keller (2005) opines that impaired learner often shows an ever increasing gap in vocabulary growth, complex sentence comprehension and construction, and in concept formation as compared to pupils with normal hearing ability.
The main problem of hearing impaired pupil is communication, as such pupil cannot effectively hear the teacher's voice. It is therefore important to understand the peculiarity of the impaired learners, to have the right instructional media selected for their teaching/learning process. Instructional media enhance learning and increase the interest of learners in teaching and learning. They also help in assimilation and retention because what is seen can be easily retained and remembered by learners.
Obat (2002) identifies supporting strategies and instructional media that hearing impaired pupils may use to manage their academic, they are lip reading, sign language, hearing equipment such as hearing aids, radio microphone and induction loops, television and computer. Pupils who are deaf or hard of hearing usually rely on lip reading, while those who are profoundly or prelinqually deaf are more likely to use sign language. Lip reading requires intense concentration and is tiring over long periods. Sign language is an independent language and it is capable as a spoken language in conveying meanings and ideas. It has its own punctuation and grammar. It can also communicate complex theories and concepts.
Many different assistive technologies are available to those who are hearing impaired. People with cochlear implants and hearing aids or neither of these can also use additional communication devices to reduce the interference of background sounds, or to mediate the problems of distance from sound and poor sound quality caused by reverberation and poor...