Learning disability

Question 1

What is included in the subsets of mental disorder accordion to legislation?

Answer 1

• Mental illness
• Personality disorder
• Learning disability

Question 2

What is the ICD-10 definition of learning disability?

Answer 2

A condition of arrested or incomplete development of the mind, which is especially characterised by impairment of skills manifested during the developmental period, which contribute to the overall level of intelligence i.e. cognitive, language, motor and social abilities

Question 3

Learning disability criteria

Answer 3

• Intellectual impairment (IQ < 70) (Wechsler)
• Social or adaptive dysfunction (Vineland Scale)
  
  • Deficits/Impairments in 2 or more of following adaptive skills: communication, self-care, home living, social skills, community use, self direction, health and safety, functional academics, leisure & work
• Onset in the developmental period (age 18)

Question 4

Statistically the prevalence of people with IQ<70 should be 2.5% (2SD from mean).

Actually the prevalence of people with LD is 1-2%, why is this?

Answer 4

• Differential mortality (the more severe the degree of learning disability, the higher the mortality c.f. general population)
• The role of functioning - those with IQ<70 but no problems functioning within their environment would not be defined as having a learning disability

Question 5

How is learning disability classified?

Answer 5

IQ is used to classify level of LD

• Mild learning disability 50 to 69
• Moderate learning disability 35 to 49
• Severe learning disability 20 to 34
• Profound learning disability <20

Question 6

Aetiology - Learning Disability

Answer 6

• Genetic: e.g.
  
  • Single gene: Fragile X
  • Microdeletion/duplication: DiGeorge Syndrome, Prader-Willie
  • Chromosomal abnormality: Down Syndrome
• Infective
  
  • ante-natal e.g. rubella;
  • post-natal e.g. meningitis, encephalitis
• Toxic: e.g. foetal alcohol syndrome
• Trauma: e.g. birth asphyxia, head injury
• Unknown: for most individuals, the cause of their LD is unknown

Question 7

Schizophrenia / Psychosis in learning disability

Answer 7

• 3% Point Prevalence compared to 1% in general population
• Associated with change in personality and reduction in functional abilities
• ‘Self-Talk’ common in LD, particularly Downs Syndrome

Question 8

Mood Disorders in learning diability

Answer 8

• Increased incidence
• Less likely to complain of mood changes and noted by change in behaviour ie biological symptoms

Question 9

OCD in learning disability

Answer 9

• Ritualistic behaviour and obsessional themes significantly increased in LD
• Obsessions hard to describe by people with LD but compulsions more readily observed

Question 10

Autism in learning disability

Answer 10

• 2/3 of persons with Autism have a LD

Question 11

Over activity syndrome in learning diability

Answer 11

• ADHD much higher incidence
• Many severe LD children are overactive, distractible and impulsive but NOT to extent that would indicate diagnosis of ADHD

Question 12

Challenging Behaviour and Self Injury in Learning Disability

Answer 12

• Mannerisms, head banging and rocking common with severe LD
• General trend is towards greater prevalence of problem behaviour with increasing severity of LD (but people with profound LD exhibit less outwardly)

Question 13

Forensic in learning disability

Answer 13

Mild LD have similar rates of offending to the general population but different profile of offending.

IQ below 70 over-represented for arson and sexual (usually exhibitionism) in prison population.