I. Mental Retardation

- IQ < 70

- deficit of adaptive behavior – (can you button pants, make ice w/out recipe, and other activites required for daily life functioning)

- Onset before age 18

• Intelligence Testing

- Welchsler is gold standard

WISC (Wechsler Intelligence Scale for Children)

WAIS (Wechsler Adult Intelligence Scale)

- 100 is average

- Produces a full scale composite score, verbal score, and a performance score

Important to look and see if performance or verbal is more pronounced to determine where the persons strengths lie

- “Full Scale” score used for diagnosis

- Significant difference between verbal and performance scales referred to as a “split” ( > 10 pt difference- may indicate learning disability so it is important to look at the split core and not just the total score)

- Implications of a significantly higher verbal score – visual/motor impaired; child assumed to be more intelligent than they are

- Implication of a significantly- people don’t realize the person has specific skills

• Assessing Adaptive Behavior

- Vineland Adaptive Behavior Scale (Gold standard)

To meet screening for MR you must have some adaptive behavior deficit; intende to differentiate kids who do poorly on an IQ exam (score accurate) but functional level is what it should be from MR

easures

~ ability to love independently

~ hold some type of job

~ form friendships

- provide some degree of care for others

Scaled scores with 100 as average

• Prevalence and Severity

- Generally reported as ~ 1% prevalence

- Severity levels

~ Mild (50-55 to 69)

~ Moderate (35-40 to 50-55)

~ Severe (20-25 to 35-40)

~ Profound (below 20-25)

- IQ’s in the range 70-80 referred to as “Borderline Intellectual Functioning”

• Functional Level

- Mild- ~ 90% of the MR population

If not dysmorphic, may go undetected early on

Academic level of about the 6^th grade; it may take them much longer to get there (Jethro had a 6^th grade diploma

~ Employable

~ May live relatively independently

- Moderate

5% of the MR population

~ Developmental delays early on milestones delayed (parents defect earlier than mild)

~ Academic level of about 2^nd grade

~ More adjustment difficulties in adolescence- kids don’t fit in as well and have more

behavioral problems ↑depression, adjustment, etc.

~ More structure in living and employment situations- must be more monitored

- Severe (3-4%) of MR population

Extremely delayed milestones

Academic training of little benefit

Need constant structure

- Profound (1-2%) of the MR population

May develop communication and basic self care skills

Live long support needed (SEVERE)

*The lower the IQ, the less precise the boundaries are

• Etiology

- Unknown in many cases

- Organic/environmental factors

Prenatal injury- toxicity or infection (FAS)

Perinatal factors- prematurity, trauma, hypoxia

Childhood – toxicity (ie lead poisoning), trauma, infection (meningitis, encephalitis, etc), hypothyroidism

- Genetic Factors

Downs syndrome (↓ lifespan)

~ Most common autosomal defect – trisomy 21, translocation 18, mosaicism

~ Characteristic clinical features

~ High incidence of Alzheimers (30′s)

Fragile X (assoc w/ MR)

Other genetic factors are poorly defined

• Emotional Problems

- More mental and emotional problems than in non-retarded people

- Autism

- Adjustment difficulties (especially for moderate MR)

- Affective problems – depressed, bipolar, etc

- Behavioral difficulties – frustration, tolerance, moderating anger ↓, etc.

Basically any kind of psychotic illness can be seen in MR kids as in normal kids, but they have a slightly different clinical presentation (i.e. MR child might think their stream of consciousness is an auditory hallucination)

II. Autism and the Pervasive Developmental Disorders

- Group of disorders characterized by delays and disturbance in social and communicative development, and behavior

- Onset in infancy or childhood

- Often associated with MR

- Autism and Pervasive Developmental Disorder, NOS (PDD) most common in the group

• Prevalence

- Autism

~ 2 cases per 10,000

~ M > F (4-5:1)

~ all SES levels

- PDD – similar Sx to autism but fewer in #, impairment slightly less than autism

~ 1 case per 200 population

- Other diagnoses less common

• Diagnosis of Austism

- Onset in infancy and childhood- most evidence Sx in 1^st 2 yrs

- Sx in 3 Major areas

1. Impaired social relationships

2. Impaired verbal communication (verbal and nonverbal)

3. Restricted or limited range of activities or interests

• Specific Symptoms

- Impaired social relationships

“Autistic” – lack of interest in relationships- autistic kids don’t have thought d/o so they are not considered schizophrenic but they may have similar behavior problems to schizo’s

Lack of eye contact

Poor attachment

Do not seek others for comfort when stressed

Lack of imitative behavior

* Hard for parents!!!

- Impaired Communication

Delay or speech development- many may not have communicative speech

Echolalia

Odd intonation or cadence (dysprosody)

Idiosyncratic use of words

Failure to use language for social interaction

- Restricted or limited range of activities or interests

Interest in repetative movements or motions- rocking endlessly, etc.

Unreasonable insistence on sameness, ritual, or routine- anxiety if can’t do routine

Interest in parts of objects rather than the whole- spin wheel of mini car endlessly, don’t pretend as much, don’t build much with blocks

Change may result in anxiety or behavioral outbursts

• Other Features

- May engage in self-injurious behaviors- bang heads, bite themselves causing injury

- May develop seizures in adolescence

- May have motor abnormalities

- A few will have “savant” abilities (rain man memories…memorizing phone book, etc)

~ Musical or drawing skills

~ Memory skills (“calendar calculations”)- “it is October 4, 1999″ and they know its Tuesday

• Etiology

- Not very clear, likely multi-factorial (We really don’t know)

- Thought to be related to an unknown neurobiological processes

- Some genetic component postulated

- Not related to parenting practices

- No specific biological marker

• Differential Diagnosis

- Developmental language disorder

- Sensory impairment

- MR

- Childhood psychosis

• Treatment

- NO specific medication to treat- may help for certain target Sx like behavioral probs

- Intervention can be challenging- very accustomed to routines

- Educational and behavioral interventions

- Given lack of definitive treatment, many unproven interventions have arisen

• Outcome

- 1/3 achieve some level of personal and occupational independence

- Even those that improve tend to retain some impairment in social functioning

- Prognosis better with

1. IQ > 50

2. Speech devo BEFORE age 5

• Other Diagnoses

- PDD

More common than autism

Same Sx groups but exhibit fewer symptoms

- Asperger’s disorder

No impairment of language skills

Usually normal IQ (avg intelligence)

- Childhood Disintegrative Disorder

Normal Devo until age 2

Loses verbal and motor skills previously acquired

- Rett’s Disorder

Extremely rare

Deceleration of head circumference growth after period of normal growth

Impairment of verbal skills

• Specific Developmental Learning Disorders

- Academic Skills Disorders – normal or above IQ but have certain areas they can’t function well in

Arithmetic disorder

Expressive writing disorder

Reading disorder

- Language and Speech Disorders

Articulation Disorder

Expressive language disorder – kid has difficulty with verbal expression

Receptive language disorder – kid has trouble decoding info they receive

Tags: Assessing Adaptive Behavior, borderline Intellectual Functioning, Downs Syndrome, dysmorphic, hypothyroidism, Hypoxia, prematurity, trauma, WAIS, Wechsler Adult Intelligence Scale, Wechsler Intelligence Scale for Children, WISC

This entry was posted on Saturday, September 5th, 2009 at 5:00 am and is filed under Behavioral Science and Psychiatry. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.