Special Populations

Mental Retardation

Degrees of Severity

_ Mild mental retardation

_ Moderate mental retardation

_ Severe mental retardation

_ Profound mental retardation

 

Mild mental retardation

_ IQ level from 50-55 to 70

_ Formerly called "educable"

_ About 85% of MRs

_ By late teens, academically at the sixth-grade level

_ Social & vocational skills for self-support

_ May need supervision, guidance, assistance for some activities

 

Moderate mental retardation

_ IQ level from 35-40 to 50-55

_ Formerly called "trainable"

_ About 10% of MRs

_ Vocational training, personal care possible

_ Academically, second grade level

_ Can perform unskilled or semiskilled work under supervision in sheltered workshops or in the general work force

 

Severe mental retardation

_ IQ from 20-25 to 35-40

_ About 3-4% of MRs

_ In early childhood, do develop little or no speech communication

_ Acquire little knowledge of the alphabet or counting, but some survival sight words

_ Live in group homes or with family

 

Profound mental retardation

_ IQ below 20-25

_ 1-2% of MRs

_ Considerable impairments in sensorimotor functioning

_ Require constant aid and supervision from caregiver

 

Mental retardation - diagnostic criteria

_ Significant subaverage IQ (70 or below)

_ Impairments in adaptive functioning, e.g.

_ Communication

_ Self-help; self-direction

_ Social/interpersonal skills

_ Functional academic skills

_ Work

_ Safety

MR- etiology

_ Idiopathic (30-40%)

_ Genetic (5%)

_ Fragile X, Down

_ Embryonic development (30%)

_ Down syndrome, Fetal alcohol syndrome, infections

_ Pregnancy/perinatal problems (10%)

_ Hypoxia, infection, malnutrition

_ Acquired (5%)

_ Trauma, lead poisoning

_ Mental disorders (15-20%)

_ Deprivation, autisitic disorder

 

Down Syndrome

_ 1:600 live births

_ 1:50 with women over 44 years

_ Associated congenital heart defects

_ Leukemia

_ Immunological deficiencies

_ Very good social skills

_ Mental retardation

 

Down Syndrome Characteristics

_ Short stature _ Flat philtrum _ Low set ears _ Protruding tongue _ Dental anomalies

Down syndrome characteristics

 

_ Hypotonia

_ Protruding stomach

 

_ Short and stubby hands and feet _ Prominent crease _ Clinodactyly _ Dry, scaly, inelastic skin

Down syndrome eye characteristics

_ Oblique palpebral fissures

_ Prominent epicanthal folds

_ Strabismus

_ Keratoconus

_ Iris hypoplasia

_ Crowded disc

 

Fragile X Syndrome

1:1000 males MR Oblong face Large ears Large testicles ADHD Autistic-like behavior

Fetal Alcohol Syndrome

_ Mental retardation _ Height and weight maldevelopment _ Craniofacial anomalies _ Cardiovascular and urogenital system disorders _ Optic Nerve hypoplasia _ Anterior segment abnormality, so à IOP

Autistic disorder

_ Presence of markedly abnormal or impaired development in social interaction and communication

_ And

_ A markedly restricted repertoire of activity and interests

_ 4-5:10,000

_ Boys 3-4/1

Autistic disorder -social interaction

_ Failure to develop peer relationships

_ Lack of spontaneous seeking to share enjoyment, interests, etc. with other people

_ Lack of social or emotional reciprocity

_ Impaired use of nonverbal communication

_ Eye-to-eye gaze, etc.

Autistic disorder - communication

_ Delayed or total lack of spoken language

_ Impaired initiation or sustained conversation

_ Repetitive use of language

_ Often thought to be hearing impaired prior to diagnosis

Autistic disorder - stereotyped behavior

_ Repetitive motor mannerisms

_ Persistent preoccupation with parts of objects

Autistic disorder - associated features

) ADHD

) Aggressiveness

) Self-injurious behaviors

) Temper tantrums

) Oversensitivity to touch, sounds

Cerebral Palsy

_ Nonprogressive motor dysfunction of varying severity

_ Onset at birth

_ Hypotonicity to hypertonicity

_ 1-2:1000 live births

_ Spastic quadriplegia, diplegia, hemiplegia, paraplegia

_ Mental retardation in at least 50% of CPs

_ Seizure disorder

 

Cerebral palsy - ocular findings

_ Nystagmus

_ Gaze limitations

_ Strabismus

_ Optic atrophy

 

Clinical decision making for special populations

_ Alternative testing procedures (remember these for young children and infants)

_ Presbyopia (don't forget that special populations also get presbyopia, so don't forget to prescribe for near point tasks)

_ Prescription for refractive error (especially large errors; however, don't underestimate the importance of a proper refractive correction to allow the patient to function to maximum potential)

_ Evaluate functional visual needs

_ Listen to parents, caregivers, therapists

_ What tasks or jobs does the individual engage

_ Rely on objective findings

_ Retinoscopy, Cover test, etc.

_ VEP (only occasionally needed)

_ Have realistic expectations, but give the special needs patients full consideration

Clinical decisions for special populations

_ Strabismus prognosis is generally poor

_ Vision therapy can be useful and effective in the right cases

_ Use lenses, prisms

_ Get feedback from parents, teachers, caregivers