Understanding Visual and Auditory Deficits: Early Detection and Intervention

Posted on Apr 6, 2025 in Naval Architecture and Marine Engineering

Visual Deficit

1.1. Sight:

1. Sense that allows us to keep in touch with the world and integrate information.
2. Roles/Functions:
   • Geographical orientation
   • Knowledge of the world (object perception)
   • Social relations (face perception)
     • Face and body = Signs of identity
     • Non-verbal communication (body language, facial expressions)
     • Lip-reading (visual sign for speech)
3. Route:

Eyes à Optic nerve à Optic chiasm à Optic tract à Thalamus à Visual cortex

There are persons who see and hear all but they have a cerebral damage that does not let them interpret what they are saying or showing. But they are not blind or deaf.

*Occipital lobe: the part of the brain that let us see.

*Temporal lobe: the part of the brain that let us hear.

1.2. Visual Impairment:

1.2.1. Visual Impairment Definition:

1. Inability or decreased ability, due to a deficiency in sight, to carry out everyday activities.
2. Can produce social disadvantage that will restrain or prevent performance of expected roles according to education, sex and social-cultural factors.

Differences between: deficit, disability and handicap:

1. Deficit: an alteration in the anatomy or on the function of an organ. (BIOLOGICAL) Impaired vision
2. Disability: decreased ability to carry out an activity. (PSYCHOLOGICAL=What the person can do?) Reduction of the sight ability
3. Handicap: social disadvantage that restricts performance of the expected roles (SOCIAL) Handicapped

1.2.2. Types of Visual Impairments:

1. Normal vision:
2. 50-100% of vision remains
3. Normal life, no adaptations needed
4. Low vision:
5. Visual acuity 30-50% or visual field <>
6. Need for support and adaptations
7. Blindness:
8. Total inability to use vision because:
   • Very low visual remains, not useful (partial blindness)
   • No visual remains, only light and shades
9. ONCE: visual acuity <>
10. WHO (OMS): visual acuity 10-30% +field <>

1.3. Early Detection:

1. Signs of alarm:

• Strabismus (cross eyed)
• Blinking
• Eye watering
• Eye swelling
• Dizziness
• Headaches
• Nausea
• Blurred vision
• Rigid postures
• Attention deficits
• Getting very close or far away from object/TV

Auditory Deficit

1.1. Auditory System:

1. Route:

External auditory canal à Tympanic membrane à Tympanic cavity à Cochlea à Vestibule-cochlear nerve à Midbrain à Thalamus àCortex

1.2. Auditory Deficit:

1. Pathological state of the hearing sense that:
2. Prevents receiving useful auditory stimuli and development of language (if congenital)
3. Provokes forgetting of language (if acquired)

1. Hearing (and hearing loss) loss is measured in: dB (arbitrary measure of auditory intensity)
2. Consequences:
3. Decrease of cognitive-linguistic development
4. Decrease of social-affective development

1.3. Degrees of Auditory Deficit:

1. Hypoacusis:
2. Hearing diminished but allows language development
3. i.e. hearing remains can be put to use
4. If mild, spontaneous language development
5. If moderate, necessary systematic programme + technical aids
6. Deafness:
7. Does not allow language development
8. Necessary use of signs
   1. According to degree of hearing loss:

   Type of hypoacusis	Description/Implications
   Normal hearing	Learns to speak hearing others
   Mild hypoacusis	Punctual speech support
   Moderate hypoacusis	Difficulties hearing from a distance; prosthesis + therapy needed
   Severe hypoacusis	Language development, deficitary and late; systematic therapy needed
   Deep hypoacusis = Deafness	No hearing at all; sign language (and or lip-reading)

   B. According to organs affected:

   1. Conductive: outer and/or middle ear
   2. Neurosensory or perceptual: inner ear (cochlea)
   3. Mixed/Combined

   C. According to moment of appearance:

   1. Prelocutive: before the elements of language: speaking and listening, reading and writing. The hearing in permanent is acquired before language has been fully developed
   2. Postlocutive: after the elements of language. The hearing in permanent is acquired after language has been fully developed.

   -Educational implications: maybe the way to treat them is different, because postlocutive has the structure language still in their mind.

   -Language is developed at 4-5 age. Here, the language is very similar to the adult language.

1.5. Early Detection:

*No vocal emissions: with 2 months the pupil starts to do sounds like “ajo”

*Does not respond: does not look at the place which is the sound

*Expression: speaking and writing // Comprehension: listening and reading

1. Intervention:

Vision impairments: Braille

• Auditory impairments: AACS

Visual impairments: Braille

What is the origin of Braille?

Valentin Hauy (1795) created the Institute of Blind Youth (IJC) in Paris and invented the first reading and writing system for the blind: wooden blocks with carved letters. Subsequently,

Charles Barbier (1808) created a nocturnal writing method, based on a dot alphabet, so that soldiers could communicate at night without being overheard.

Louis Braille (1809-1852) was born with sight but lost it as a child. He was first a student and then a teacher, and he adapted Barbier´s method for the blind.

1. How does it work?

6 dots is the maximum that can be perceived with the fingertip. Braille consists of cells (2.5x5mm) with 2 columns and 3 rows of carved dots. One number corresponds to each dot:

Braille allows to read letters, numbers, punctuation, music keys and Mathematical signs.

64 cells are used.

1. How can we read and write in Braille?

The dots are written on relief (sticking out) with a punch (in Sp. “punzón”) and a Braille board (in Sp. “regleta” or “pauta”). This board is formed by 2 (joined) plastic or metal layers. The one at the bottom has small rectangles, each with 6 dots. The one on top has cells. Each cell corresponds to one rectangle with its 6 dots.

Auditory impairments: AACS

1. Cochlear implants: the most frequency. Through surgery, we introduce a mechanism that is equivalence to the function of the cochlear. Obviously, it is very helpful, but it is not exactly the same, so the child has to adapt to it.
2. Intervention in language: Augmentative and alternative communication systems:
3. Alternative systems substitute oral language. Augmentative systems support it, they do not substitute it.
4. Sign language is not universal, it is a naturally developed language and is restricted by geographic and cultural factors, just like oral language. Language with its own grammar and rules. (WORD)
5. Bimodal is an artificial system that is more universal than sign language but also affected cultural aspects. System with only vocabulary, not grammar.
6. Manual alphabet can be signed with one hand (Spanish) or 2 (English). Signs written letters in the alphabet (LETTERS).
7. Cued speech uses one hand. Signs syllables, but their sounds, not their written form. (SYLLABLES-SOUNDS). Pa-pá; Ca-sa; Que-so; Ce-ni-ce-ro.