PART I: FOUNDATIONAL CONCEPTS AND DEFINITIONS
Table: Foundational Concepts in Learning Disability
| Category | Topic / Syndrome | Key Points & Details | Exam Hook / Pearl / High-Yield Facts |
|---|---|---|---|
| Foundational Concepts | Terminology | • Learning Disability (LD): Preferred UK term (Dept. of Health, Valuing People etc.). Refers to a global impairment of intellectual (IQ) and adaptive functioning with an onset before 18 years. • Intellectual Disability (ID) / Intellectual Developmental Disorder: DSM-5 and ICD-11 term. Synonymous with Learning Disability for exam purposes. • Mental Retardation (MR): ICD-10 and older term. Now considered obsolete and offensive but may still appear in exam stems. | Trap: Do not confuse Learning Disability (global impairment, IQ <70) with a specific Learning Difficulty (e.g., dyslexia, dyscalculia, dyspraxia), which involves a specific academic problem with a normal or high IQ. LD ≠ dyslexia. |
| Foundational Concepts | Core Definition (Tripartite) | ALL THREE of the following criteria must be met: 1. Impaired Intelligence: An IQ score of approximately ≤70 (at least two standard deviations below the population mean of 100). This affects global functions like reasoning, problem-solving, planning, abstract thinking, and learning from experience. 2. Impaired Adaptive / Social Functioning: Significant difficulty and deficits in meeting age- and culture-expected standards in one or more of the following domains: • Conceptual: Language, reading, writing, maths, time, money, judgement, problem-solving. • Social: Empathy, social cues, friendships, social judgement, vulnerability to exploitation. • Practical: Personal care (ADLs), domestic tasks, finances, work, transport, safety. 3. Developmental Onset: The impairments must occur during the developmental period, before the age of 18. | Pearl: An adult who sustains a severe Traumatic Brain Injury (TBI) and now has an IQ of 60 has an Acquired Brain Injury, NOT a Learning Disability. An individual with an IQ of 65 but who is fully independent, married, and holds a full-time job has NO Learning Disability. |
| Foundational Concepts | Severity Classification | • Mild: IQ 50–69 (~85% of all cases). Can achieve late primary school academic level (~11 yrs). Independent self-care but needs help with complex tasks (budgeting, legal). • Moderate: IQ 35–49 (~10% of cases). Simple language, limited reading/writing. Needs considerable support for self-care and lifelong supported living. • Severe: IQ 20–34 (~3-4% of cases). Very limited or no speech. Needs help for all ADLs, 24-hour supervision. Frequent motor/neurological problems. • Profound: IQ <20 (~1-2% of cases). No symbolic understanding. Fully dependent for all care, multiple physical and sensory disabilities. • Borderline Intellectual Functioning: IQ 70–85. This is Not LD, but represents a vulnerability, especially with complex demands or under stress. | Fact: The vast majority of people with a Learning Disability fall into the Mild category. |
| Foundational Concepts | Key Concepts & Frameworks | • Normalisation: The principle of enabling individuals to live a life with patterns and conditions as close as possible to those of ordinary society (e.g., living in your own home, having a normal daily routine, making choices). • Deinstitutionalisation: The historical process of closing long-stay hospitals and institutions and moving people into community-based living settings. It is a one-time structural change. • Social Role Valorisation (SRV): The principle of actively supporting individuals to hold socially valued roles within their community (e.g., employee, volunteer, tenant, student) to increase their status and inclusion. | Hook: • "Living independently in their own flat" = Normalisation • "The closure of the local long-stay hospital" = Deinstitutionalisation • "Getting a job at the local café" or "Becoming a volunteer" = Social Role Valorisation (SRV) |
| Foundational Concepts | Diagnostic Overshadowing | ULTRA HIGH-YIELD. The tendency to attribute all new symptoms, whether physical or mental, to the person's existing learning disability. This leads to missed or delayed diagnoses of treatable conditions. Common Scenarios: • New aggression is attributed to the LD, but is actually caused by a dental abscess, constipation, pain, infection, depression, or psychosis. • Anxiety symptoms are dismissed as "just part of their Down's Syndrome". | Rule: In an exam vignette, a new change in behaviour (e.g., aggression, withdrawal, self-injury) is almost NEVER "just part of the LD." The correct answer will always involve investigating for an underlying cause like pain, physical illness, or a new mental illness. A new onset of aggression could be due to a dental abscess, constipation, or depression. |
| Foundational Concepts | Other Key Concepts | • Flynn Effect: The observed rise in IQ scores over decades means that older, outdated test norms can overestimate a person's IQ. Using up-to-date, standardised tools is crucial to avoid misclassifying someone as borderline instead of having a mild LD. • Makaton: A language programme that uses signs and symbols alongside speech to support communication. It aids spoken language, it does not replace it, and signs follow the spoken word order. • Global Developmental Delay (GDD): A term used for children, typically under 4-5 years, who show significant delays in two or more developmental domains (e.g., motor, speech, cognitive, social). A formal LD diagnosis is deferred until IQ testing is more reliable. | Hook: The Flynn Effect means old tests can give a falsely high IQ score. The clinical application of avoiding diagnostic overshadowing is to always consider physical causes (pain, constipation, infection) for new challenging behaviour. |
| Epidemiology & Co-morbidity | Prevalence of LD | • Overall: Affects 1-3% of the general population (20-30 per 1000). • Severe LD (IQ <50): Has a stable prevalence of 3-4 per 1000 across different populations, as it is more often linked to specific biological causes. • Male:Female Ratio: Approximately 1.5 : 1, partly due to X-linked causes. • Highest Detection: Occurs during school age (10–14 years). | Fact: The prevalence of severe LD is more stable across studies and populations than mild LD. |
| Epidemiology & Co-morbidity | Mental Health Co-morbidity | • Overall: 30-50% of adults with LD have a co-morbid mental health problem (including challenging behaviour). • Schizophrenia: Prevalence is 3-4% (approximately 3-4 times higher than the general population rate of ~1%). • Depression: ~4%. Often presents atypically with aggression, withdrawal, SIB, or loss of skills rather than expressed low mood. • Bipolar Disorder: ~1.5%. • Anxiety Disorders: ~4%. • Autism (ASD): Very high co-morbidity. Affects ~7.5% of the overall LD population, but rises to 40% in those with severe LD. | MUST MEMORISE: The rate of schizophrenia in the Learning Disability population is 3-4%. This is one of the most frequently tested epidemiological facts. |
| Epidemiology & Co-morbidity | Physical Health Co-morbidity & Inequalities | • Premature Mortality (CIPOLD report): People with LD die significantly earlier than the general population. Men die on average 13 years earlier, and women 20 years earlier. Many of these deaths are preventable. • Epilepsy: Prevalence is 20-25% overall, rising to 50% in those with profound LD. • Other Common Issues: Sensory impairments (hearing loss ~25-42%, visual ~19%), obesity (~24-29%), constipation, dental problems, Gastro-Oesophageal Reflux Disease (GORD), and respiratory disease. • Barriers to care: Communication difficulties, diagnostic overshadowing, poor professional training, and system barriers (e.g., accessibility). | Hook: Epilepsy is the most significant neurological co-morbidity. Unexplained pain from common but missed issues like constipation or dental problems is a major cause of challenging behaviour. |
| Aetiology & Prevention | Causes (Aetiology) | • Genetic: The largest identifiable group of causes. Includes chromosomal abnormalities (e.g., Down's, Fragile X), microdeletions (e.g., PWS, Angelman, 22q11.2), and single gene disorders (e.g., Tuberous Sclerosis, Rett). • Prenatal: External factors during pregnancy. Includes maternal infections (TORCH), toxins like alcohol (Fetal Alcohol Spectrum Disorder - FASD is the leading preventable cause), drugs (e.g., sodium valproate), and severe maternal illness. • Perinatal: Events around the time of birth, such as hypoxic-ischaemic injury, extreme prematurity, low birth weight, trauma, and neonatal infections. • Postnatal: Events after birth, including head injury (accidental or non-accidental), Central Nervous System (CNS) infections (meningitis, encephalitis), lead poisoning, and profound psychosocial deprivation. • Unknown: The specific cause remains unidentified in approximately 30% of severe and up to 75% of mild cases. | Hook: Remember the TORCH acronym for key prenatal infections: Toxoplasmosis, Other (Syphilis), Rubella, Cytomegalovirus, Herpes. |
| Aetiology & Prevention | Prevention Levels | • Primary Prevention: Prevents the condition from occurring in the first place. Examples include folic acid supplementation, immunisation programmes (e.g., for rubella), and public health campaigns about alcohol use in pregnancy. • Secondary Prevention: Aims for early detection and treatment to reduce the impact or severity of the condition. Examples include newborn screening for Phenylketonuria (PKU) and congenital hypothyroidism. • Tertiary Prevention: Manages an established condition to improve quality of life and reduce disability. Examples include special education, speech and language therapy, occupational therapy, and management of co-morbidities. | Classic Exam Question: The Guthrie test (newborn blood spot screen) for PKU is the quintessential example of Secondary Prevention. |
| Behavioural Phenotypes | Down Syndrome | Genetics: Trisomy 21 (95% due to maternal non-disjunction). Features: Sociable and affectionate but can be stubborn. Mild to moderate LD. High risk of early-onset Alzheimer's dementia, hypothyroidism, heart defects. | Hook: The APP gene (Amyloid Precursor Protein) is located on Chromosome 21, which is the direct reason for the very high risk of early-onset Alzheimer's. |
| Behavioural Phenotypes | Fragile X Syndrome | Genetics: X-linked dominant (FMR1 gene CGG repeat expansion). Features: Gaze avoidance, social anxiety, hyperactivity (ADHD features), hand-flapping, echolalic speech. Physical signs include long face, large prominent ears, and macro-orchidism (enlarged testes) post-puberty. | Hook: The most common inherited cause of LD. Think social anxiety + ADHD features. |
| Behavioural Phenotypes | Prader-Willi Syndrome (PWS) | Genetics: Deletion on paternal chromosome 15q / Maternal Uniparental Disomy (UPD). Features: Infant hypotonia and poor feeding, followed by an insatiable appetite (hyperphagia) leading to obesity. Also associated with skin picking, temper tantrums, and OCD-like behaviours. | Hook: Hyperphagia (insatiable hunger) is the key, pathognomonic feature. |
| Behavioural Phenotypes | Angelman Syndrome | Genetics: Deletion on maternal chromosome 15q / Paternal Uniparental Disomy (UPD). Features: Severe LD, minimal speech, ataxia (jerky movements), seizures, and a "happy puppet" demeanour characterized by frequent, inappropriate laughter and smiling. | Hook: The "happy puppet." |
| Behavioural Phenotypes | Rett Syndrome | Genetics: X-linked dominant (MECP2 gene mutation). Affects girls almost exclusively. Features: Normal development for the first 6-18 months, followed by regression with loss of purposeful hand skills, decelerated head growth, and development of stereotyped hand-wringing movements. Seizures are common. | Hook: Hand-wringing in a girl with developmental regression is the classic vignette. |
| Behavioural Phenotypes | Lesch-Nyhan Syndrome | Genetics: X-linked recessive (HGPRT enzyme deficiency). Features: Hyperuricemia (leading to gout and kidney stones), dystonia, choreoathetosis, and severe, compulsive self-mutilation, particularly biting of the lips and fingers. | Hook: The combination of severe self-mutilation and high uric acid is diagnostic. |
| Behavioural Phenotypes | Smith-Magenis Syndrome | Genetics: Deletion on chromosome 17p. Features: Repetitive self-hugging or "hug and flip" motion, an inverted sleep-wake cycle (sleepy during the day, active at night), severe self-injurious behaviour (e.g., nail pulling), hyperactivity, and a characteristic square-shaped face. | Hook: The self-hugging is considered pathognomonic. |
| Behavioural Phenotypes | Williams Syndrome | Genetics: Deletion on chromosome 7q. Features: "Elfin" facial features, hypersociability ("cocktail party speech") with a lack of social inhibition, marked anxiety, specific phobias, and hyperacusis (sensitivity to sound). Medical issues include supravalvular aortic stenosis. | Hook: The overly friendly, talkative child with LD. |
| Behavioural Phenotypes | Cri-du-chat Syndrome | Genetics: Deletion on chromosome 5p. Features: A high-pitched, cat-like cry in infancy, microcephaly, hypertelorism (wide-set eyes), and severe LD. | Hook: The cat-like cry is the defining feature. |
| Behavioural Phenotypes | VCFS / DiGeorge / 22q11.2 Deletion Syndrome | Genetics: Deletion on chromosome 22q11.2. Features: Remember CATCH-22: Cardiac defects, Abnormal facies, Thymic hypoplasia, Cleft palate, Hypocalcaemia. Associated with LD and a very high risk of schizophrenia-like psychosis (up to 30%). | Hook: The genetic syndrome with the highest risk of psychosis. |
| Behavioural Phenotypes | Tuberous Sclerosis | Genetics: Autosomal Dominant (TSC1/TSC2 genes). Features: Skin lesions (Ash-leaf spots, facial angiofibromas, shagreen patches), cortical tubers in the brain, seizures (especially infantile spasms), renal angiomyolipomas, LD, and autism. | Hook: The triad of skin lesions + seizures + LD. |
| Behavioural Phenotypes | Neurofibromatosis Type 1 (NF1) | Genetics: Autosomal Dominant (NF1 gene). Features: Multiple café-au-lait spots (≥6), axillary (armpit) freckling, cutaneous neurofibromas, and Lisch nodules (on the iris). LD is present in some, with high rates of ADHD and anxiety. | Hook: The "coffee spots and freckles" syndrome. |
| Management | General Principles & Challenging Behaviour | • First Line: Always non-pharmacological. The first step for any new challenging behaviour is a Functional Behavioural Analysis (FBA), often using ABC (Antecedent-Behaviour-Consequence) charts, to understand its function. • Positive Behaviour Support (PBS): A framework to understand and manage behaviour by modifying the environment, teaching new skills, and changing reinforcement patterns. • Pharmacology: Should only be used to treat a diagnosed co-morbid condition (e.g., psychosis, depression), not just a behaviour. Always "start low, go slow." • Challenging Behaviour: Behaviour that puts safety at serious risk or seriously restricts access to ordinary community life. Always exclude physical causes first (pain, constipation, GORD, infection). | Rule: For any new challenging behaviour, the first step is Functional Behavioural Analysis. Medication is not the first answer. Always think BIO-PSYCHO-SOCIAL. |
| Management | Specific Behaviours (SIB & Pica) | • Self-Injurious Behaviour (SIB): Repetitive acts causing physical harm (head banging, biting). More common in profound LD, autism, and sensory deficits. The endogenous opioid hypothesis (self-injury releases opioids, reinforcing the behaviour) is a rationale for trying naltrexone. • Pica: Persistent eating of non-food substances. Can lead to poisoning, obstruction, or infection. | Hook: SIB is strongly associated with syndromes like Lesch-Nyhan (mutilation), Prader-Willi (skin-picking), and Smith-Magenis (nail pulling). |
| Management | Pharmacology: Antipsychotics | • Evidence: Risperidone has the best evidence base for the short-term treatment of severe aggression, irritability, and self-injury in the context of LD and ASD. • Monitoring: Monitor closely for metabolic side effects (weight gain, dyslipidaemia, glucose dysregulation) and Extrapyramidal Side Effects (EPSEs), especially akathisia, which can mimic agitation and worsen behaviour. | Hook: Be aware of medication-induced dysphagia (swallowing difficulty) as a serious side effect of antipsychotics and other sedating medications, which can lead to aspiration. |
| Management | Pharmacology: Lithium | • Indications: Used for bipolar disorder, augmentation in depression, and aggression. • Licensed Indication: Uniquely licensed in the UK for the "control of aggressive behaviour or intentional self-harm" in individuals with a learning disability. • Precautions: Requires a baseline EEG in the LD population due to the risk of lowering the seizure threshold, especially if there is a pre-existing abnormality. | MUST MEMORISE: The specific licensed indication for aggression/SIB and the requirement for a baseline EEG in the LD population before starting lithium. |
| Management | Psychological Therapies | • Behavioural (ABA/PBS): The core and first-line approach for addressing challenging behaviour through functional analysis and skill-building. • Adapted Cognitive Behavioural Therapy (CBT): Can be effective for anxiety and depression in mild LD. Adaptations include simpler language, use of visual aids, shorter sessions, repetition, and carer involvement. • Social Stories: Highly recommended, structured narratives used to reduce anxiety and explain social cues and situations, particularly for individuals with ASD. | Hook: A simple visual tool like a "Now and Next" card is a practical technique used to help manage transitions and reduce associated anxiety. |
| Management | Epilepsy Syndromes | • West Syndrome (Infantile Spasms): Onset at 4-6 months. The triad consists of: 1. Infantile spasms ("salaam attacks"). 2. Hypsarrhythmia on EEG. 3. Developmental regression. • Lennox-Gastaut Syndrome (LGS): Onset at 3-5 years, often evolves from West Syndrome. The triad consists of: 1. Multiple seizure types (especially tonic and atonic "drop attacks"). 2. Slow spike-and-wave pattern (<2.5 Hz) on EEG. 3. Intellectual disability. | Hook: Infantile spasms are a key feature of Tuberous Sclerosis. |
| Legal & Ethical | Consent, Capacity & Legal Frameworks | • Consent: Can be withdrawn at any stage, even after it has been given. This is a fundamental ethical principle. • Capacity: Must be assessed for each specific decision (it is task-specific). The person must be able to understand, retain, weigh, and communicate the decision. • Refusal of Treatment (Mild LD): If a person with capacity refuses treatment, the first step is to explore their reasons, explain again, address misunderstandings, and postpone if appropriate; it is not to coerce them. • Bournewood Case: A landmark legal case (HL v UK, 2004) concerning the unlawful deprivation of liberty of an informal patient who lacked capacity. It led to the creation of the Deprivation of Liberty Safeguards (DoLS). The core principle is protecting the autonomy and human rights of incapacitated adults. | Hook: The Bournewood case is the key legal precedent for DoLS and the legal framework protecting the rights of incapacitated adults in care homes and hospitals. |