Unit III: ASD & Visual Impairment (VI) & Hearing Impairment (HI)

1. VI & HI: Concept and definition

2. Characteristics of VI & HI

3. Causes of VI & HI

4. Types of VI & HI

5. Educational implications for ASD children with VI& HI


1. VI & HI: Concept and definition

Sensory impairment is when one of the senses; sight, hearing, smell, touch, taste and spatial awareness, is no longer normal. Communication is the greatest challenge.

 ‘Sensory impairment’ or ‘sensory loss’ are umbrella terms used to describe loss of the distance senses i.e. sight and hearing.

You will find that the term ‘sensory impairment’ is commonly used by professionals rather than ‘sensory impaired’ individuals themselves who may be more likely to use the terms below.

There are three very distinct groups within sensory impairment:

Visually impairment or blindness

As the term indicates, a visual impairment involves an issue with sight which interferes with a student’s academic pursuits. The Individuals with Disabilities Education Act (IDEA) officially defines the category as “an impairment in vision that, even with correction, adversely affects a child’s educational performance. The term includes both partial sight and blindness.”

Definition of visual impairment as adopted in the persons with Disabilities (Equal opportunities, Protection of Right & Full Participation) Act 1995 as well as National Programme for control of Blindness (NPCB).

Blindness: refers to a condition where a person suffers from any of the following conditions, namely:

1.     Total absence of sight; or

2.      Visual acuity not exceeding 6/60 or 20/200 (snellen) in the better eye even with the correction lenses, or

3.     Limitation of the field of vision subtending an angle of 20 degree or worse

For deciding blindness visual acuity and / or field of vision are considered.

Low vision: As per PWD Act, 1995 also recognises low vision as a category of disability and defines it as follows:- “Person with low vision,” means a person with impairment of visual functioning even after treatment or standard refractive correction but who uses or is potentially capable of using vision for the planning or execution of a task with appropriate assistive device.

For teachers this definition is of no use as it does not give the range of visual acuity as well as field of vision. Practitioners therefore follow the WHO working definition of low vision- “A person with low vision is one who has impairment of visual functioning even after treatment and/or standard refractive correction, and has a visual acuity of less than 6/18 to light perception or a visual field of less than 10 degrees.”


Hearing impairment or deafness

Hearing impairment as a disability category is similar to the category of deafness, but it is not the same. The official definition of a hearing impairment by the Individuals with Disabilities Education Act (IDEA) is “an impairment in hearing, whether permanent or fluctuating, that adversely affects a child’s educational performance but is not included under the definition of ‘deafness.'” Thus, knowing the definition of deafness is necessary to understand what sort of disabilities are considered hearing impairments. A hearing loss above 90 decibels is generally considered deafness, which means that a hearing loss below 90 decibels is classified as a hearing impairment.

An inability to comprehend verbal language due to an inability to hear characterizes deafness. The official definition of deafness from the Individuals with Disabilities Education Act (IDEA) is “a hearing impairment that is so severe that the child is impaired in processing linguistic information through hearing, with or without amplification.” The phrase “with or without amplification” is significant as it indicates that a hearing aid will not provide sufficient accommodation so that the student can succeed in the classroom.

Definitions of Hearing Impairment

Person with disability act- (PWD, 1995)

·      Definition of disability in pwd act includes hearing impairment

Hearing impairment means loss of 60 decibel or more in the better ear in speech conversation frequencies.

·      Chapter 5 education have point for restructuring the curriculum for benefit of students with hearing impairment , to facilitate them to take only one language as part of their curriculum.

Centre for diseases control and prevention (CDC)

·      Refers to hearing impairment as conditions that affect the frequency and or intensity of one’s hearing. Individuals with mild to moderate hearing impairments may be “hard of hearing” but are not “deaf” these individuals differ from deaf individuals as they use their hearing to assist in communication with others


2. Characteristics of VI & HI

Characteristics of HI During childhood:

·      Delayed response to sound

·      Cannot hear clearly what others are saying

·      Show difficulty in locating the sound source

·      Pay more than usual attention to speakers’ facial expression and lip movement while listening

·      Give irrelevant answers or misinterpret instructions

·      Request for repetition during conversation

·      Show poorer ability to understand speech ` in a noisy environment

·      Tend to turn up the sound volume of television

·      Incorrect pronunciation

·      Delayed language development

·      Poor attention in class

·      Frequent use of gestures to express themselves, e.g. pointing to what they want

·      Easily irritated as a result of communication difficulty

Some of the common characteristics of deafness commonly found in classrooms include the following:

·      Difficulty following verbal directions

·      Difficulty with oral expression

·      Some difficulties with social/emotional or interpersonal skills

·      Will often have a degree of language delay

·      Often follows and rarely leads

·      Will usually exhibit some form of articulation difficulty

·      Can become easily frustrated if their needs are not met — which may lead to some behavioral difficulties

·      Sometimes the use of hearing aids leads to embarrassment and fear of rejection from peers

·      The child appears to have ‘strange’, ‘different’, ‘unclear’ speech

·      The child appears to have problem paying attention or concentrating in class.

·      The written matter of the child shows missing gaps in places of word endings like ed, ing, ly etc.

·      The child appears to be lonely, isolated, away from group activities.

·      The child brings one ear ahead while listening. (6) The child speaks too loudly or softly.

·      The child who keeps, radio, TV, tape recorder on high volume.

·      The child does not respond to a question asked from behind.

·      The child does not respond to a question asked from a distance.

·      The child does not respond to his name or a question asked from another room.

Motor Characteristics -

·      May have balance problems and these balance problems occur as a result of vestibular damage, not deafness.

·      May have a difficulty of motor speed (i.e., the time it takes the child to process information and complete a motor act).

·      The American Academy of Pediatrics notes that hearing-impaired children might appear dizzy or disoriented because the nerves in the ears also control balance

Students with visual impairments may:

Signs of a possible vision problem in a student who hasn't been diagnosed with a visual impairment include:


3. Causes of VI & HI

Conductive hearing loss Causes:

·       Malformation of outer ear, ear canal, or middle ear structures

·       Fluid in the middle ear from colds

·       Ear infection (otitis media - an infection of the middle ear in which an accumulation of fluid may interfere with the movement of the eardrum and ossicles

·       Allergies

·       Poor Eustachian tube function

·       Perforated eardrum

·       Benign tumors

·       Impacted earwax

·       Infection in the ear canal

·       Foreign body in the ear

·       Otosclerosis

Sensory-neural hearing loss Causes:

·       Exposure to loud noise

·       Head trauma

·       Virus or disease

·       Autoimmune inner ear disease

·       Hearing loss that runs in the family

·       Aging (presbycusis)

·       Malformation of the inner ear

·       Meniere’s Disease

·       Otosclerosis - a hereditary disorder in which a bony growth forms around a small bone in the middle ear, preventing it from vibrating when stimulated by sound.

·       Tumors


Conditions that may cause visual impairment

Systemic conditions

·       Diabetes

·       Hypertension (high blood pressure)

·       Cerebrovascular (brain blood vessel) disease or stroke

·       Atherosclerotic disease (cholesterol deposits in blood vessels, including those of the eye)

·       Human immunodeficiency virus (HIV)Ñusually due to infection with cytomegalovirus, a virus that affects the eye

·       Vitamin A deficiency

·       Infections involving the eyes

Some eye infections, including those caused by parasites, are more common in developing countries. Infections in a pregnant woman can affect the fetus. This type of vision loss, present from birth, is called congenital blindness.

Specific eye conditions

       Refractive errors are the most frequent eye problems. Refractive errors include myopia (near-sightedness), hyperopia (farsightedness), astigmatism (distorted vision at all distances), and presbyopia that occurs between age 40–50 years (loss of the ability to focus up close, inability to read letters of the phone book, need to hold newspaper farther away to see clearly) can be corrected by eyeglasses, contact lenses, or in some cases surgery.

       Retinitis Pigmentosa is a genetic or inherited condition. Initially it manifests as night blindness.  As the disease progresses there may be a tunnelling of vision with loss of peripheral vision followed by complete blindness.

       Macular degeneration, often called age-related macular degeneration (AMD), is an eye disorder associated with aging and results in damaging sharp and central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving. AMD affects the macula, the central part the retina that allows the eye to see fine details.

       Cataract is a clouding of the eye’s lens and is the leading cause of blindness worldwide, and the leading cause of vision loss in the United States. Cataracts can occur at any age because of a variety of causes, and can be present at birth. 

       Diabetic retinopathy (DR) is a common complication of diabetes. It is characterized by progressive damage to the blood vessels of the retina, the light-sensitive tissue at the back of the eye that is necessary for good vision. DR progresses through four stages, mild nonproliferative retinopathy (microaneurysms), moderate nonproliferative retinopathy (blockage in some retinal vessels), severe nonproliferative retinopathy (more vessels are blocked leading to deprived retina from blood supply leading to growing new blood vessels), and proliferative retinopathy (most advanced stage). Diabetic retinopathy usually affects both eyes.

       Glaucoma is a group of diseases that can damage the eye’s optic nerve and result in vision loss and blindness. Glaucoma occurs when the normal fluid pressure inside the eyes slowly rises. However, recent findings now show that glaucoma can occur with normal eye pressure. With early treatment, you can often protect your eyes against serious vision loss.

       Amblyopia, also referred to as “lazy eye,” is the most common cause of vision impairment in children. Amblyopia is the medical term used when the vision in one of the eyes is reduced because the eye and the brain are not working together properly. The eye itself looks normal, but it is not being used normally because the brain is favoring the other eye. Conditions leading to amblyopia include strabismus, an imbalance in the positioning of the two eyes; more nearsighted, farsighted, or astigmatic in one eye than the other eye, and rarely other eye conditions such as cataract.

       Strabismus involves an imbalance in the positioning of the two eyes. Strabismus can cause the eyes to cross in (esotropia) or turn out (exotropia). Strabismus is caused by a lack of coordination between the eyes. As a result, the eyes look in different directions and do not focus simultaneously on a single point.


4. Types of VI & HI

Types of Hearing Loss according to place of impairment

According to degree of hearing loss

WHO- Grades of hearing impairment-

Grade-of impairment

Audiometric    ISO value


0-No impairment

25db/ better

No or very slight hearing problems

Can hear whispers

1-slight impairment


Able to hear and repeat words spoken in normal voice at 1 meter

2-moderate impairment

41-60 db

Able to hear and repeat words spoken in raised voice at 1 meter

3-severe impairment

61-80 db

Able to hear some words when shouted into better ear

4-profound impairment

81 db or greater

Unable to hear and understand even a shouted voice


National institute for the hearing handicapped-


Type of


DB level

Word recognition score

% of



Mild hearing


26- 40


80-100 % in better


Less than 40%

     II.            a

Moderate hearing




50-80 % in better




Severe hearing




40-50 % in better




a)profound hearing




Less than 40% in better ear



b) total loss

91 and


Very poor


According to place of impairment

        conductive hearing loss – hearing loss due to the interference in the transmission of sound to and through the sense organ (outer or middle ear)

       Sensory-neural hearing loss – due to the abnormality of the inner ear or the auditory nerve, or both

        mixed hearing loss - combination of both; sometimes called a flat loss

According to the age at onset of deafness

       Congenitally deaf – born deaf

       Adventitiously deaf – born with normal hearing and became deaf through accident/illness

According to language development-

       Pre-lingually deaf – born deaf or lost hearing before speech and language were developed

       Post-lingually deaf- lost hearing after development of spontaneous speech and language

The World Health Organization uses the following classifications of visual impairment. When the vision in the better eye with BEST POSSIBLE glasses correction is:

The International Classification of Diseases 11 (2018) classifies vision impairment into two groups, distance and near presenting vision impairment.

Distance vision impairment:

Near vision impairment:


5. Educational implications for ASD children with VI& HI

There are many different characteristics and needs among children who are diagnosed as having visual impairment and autism. These characteristics may relate to the:

Blindness in itself has a significant impact on a child’s development, and if the child has additional disabilities the situation is even more challenging. Children with blindness and ASD, with and without ID, have complex needs, and the environment has a great responsibility to interpret and meet these needs to promote development and learning. For many of these children, the surrounding world can be very confusing. A constant mix of sensory stimuli can be overwhelming and even impede learning. The child’s multiple processing problems can also create conflicts regarding the choice of pedagogical approach in the teaching situation. It is important to understand and consider the child’s needs related to both the visual impairment (VI) and the ASD, and how the combination influences the child’s learning, in shaping the pedagogical methods. If either one of the disabilities is overlooked, the method is likely to fail. However, while there is a vast body of research on evidence-based practices for sighted children with ASD (Odom, 2011), very little is reported in the literature about evidence-based practices for children with ASD and blindness. Many of the methods applied for children with ASD, such as Treatment and Education of Autistic and related Communication handicapped Children (TEACCH), Applied Behavior Analysis (ABA), the Picture Exchange Communication System (PECS), visual modelling and Comic strip conversation, build strongly on images or other visual input. The general principle of the method can often be applied, but the realization and adaptation of this principle into a pedagogical reality for the child with ASD and blindness, is generally left to the individual teacher to figure out.

While many aspects of teaching children with ASD may be problematic for children who are blind, the opposite also applies. There are approaches traditionally used for children with blindness that might not work well if the child also has ASD. For example, multisensory work can be difficult, since the child with ASD might have difficulty integrating information from more than one sense and experience sensory overload. Also, hand-on-hand guidance (where the child’s hand rests on the adult’s, and follows its movements, making it possible to approach objects through tactile guidance) depends on the child’s appreciation of co-activity, which is not to be taken for granted when the child has ASD. Ideally, an effective educational program for a student with ASD and blindness should be based on the unique needs and abilities of the individual student and consider the core curriculum for both disabilities.

Although children with hearing loss and ASD present many of the same symptoms as hearing children with ASD, the diagnosis of ASD often occurs later. Both populations present with social communication and language impairments. They show delays and abnormalities in play behaviour as well as restricted activity and interests. (Steinberg, Odyssey, 2008) The following chart identifies the characteristics which may be similar or different.

For a child with a hearing loss, what are possible ‘red flags’ which may suggest that this child may also have ASD? (as cited by Szymanski and Brice, 2008, p. 12)

Because autism can impact how your child processes sound and noise, your child may struggle with learning and language. An audiologist or specialist in ASD can suggest strategies to help them cope. These strategies may include: