Síndrome de Asperger

¿Qué es el trastorno del espectro autista?

Autistic spectrum disorder (ASD) is a pervasive developmental disorder. First described by Hans Asperger in 1944, ASD lies within the autistic spectrum. Previously it was called high-functioning autism or Asperger's syndrome. The main difference from classic autism is a lack of delayed or retarded cognition and language. Those with ASD are also more likely to seek social interaction and share activities and friendships.

Classification^{1 2}

There are two major diagnostic classification systems in current use, the International Classification of Diseases version 11 (ICD-11) and the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5).

Because the disorder spectrum concept (autistic spectrum disorder, or ASD) has now been fully integrated into autism classification, the condition of AS (or Asperger's syndrome) is no longer used.

How common is autistic spectrum disorder? (Epidemiology)³

• Autism spectrum disorder (ASD) is one of the most common childhood onset neurodevelopmental disorders. The estimated prevalence in children is at least 1%.

• There are about 3-4 times more boys affected by ASD than girls, although this varies across the spectrum. Girls are more likely to have a learning (intellectual) disability.

• However, there is evidence that ASD may be under-recognised in girls without a learning (intellectual) disability.

What causes autistic spectrum disorder? (Aetiology)⁴

ASD is not a single disorder. It is now broadly considered to be a multi-factorial disorder resulting from genetic and non-genetic risk factors and their interaction.

• Se han encontrado causas genéticas, incluidos defectos genéticos y anomalías cromosómicas, en el 10-20% de los individuos con TEA. Los hermanos nacidos en familias con un sujeto con TEA tienen un riesgo 50 veces mayor de padecerlo, con una tasa de recurrencia del 5-8%. La tasa de concordancia alcanza hasta el 82-92% en gemelos monocigóticos, frente al 1-10% en gemelos dicigóticos.

• Genome-wide linkage studies suggested linkages on chromosomes 2q, 7q, 15q and 16p as the location of susceptibility genes.

• Los errores metabólicos como la fenilcetonuria, los síndromes de deficiencia de creatina, la deficiencia de adenilosuccinato liasa y los trastornos metabólicos de las purinas representan menos del 5% de los individuos con TEA.

• Se ha descrito una correlación entre el gen del patrón de desarrollo cerebeloso ENGRAILED 2 y el autismo. Es el primer alelo genético que contribuye a la susceptibilidad al TEA hasta en un 40% de los casos de TEA.

• Otros genes como el locus UBE3A, los genes del sistema GABA y los genes del transportador de serotonina también se han considerado factores genéticos del TEA.

• Varios factores ambientales también pueden contribuir al TEA, entre ellos:

  • Prenatal factors such as advanced parental age, exposure to teratogens (eg, thalidomide, maternal anticonvulsants such as valproic acid and organophosphates), maternal diabetes and certain viral infections (eg, congenital rubella syndrome, influenza, cytomegalovirus).

  • Factores perinatales como bajo peso al nacer, duración anormalmente corta de la gestación y asfixia al nacer.

  • Factores postnatales como enfermedades autoinmunes, infecciones víricas, hipoxia y toxicidad por mercurio.

Current evidence indicates that there is no harmful association between MMR vaccine and ASD even among children already at higher risk of ASD (ie children with older siblings with ASD).⁵

Autistic spectrum disorder symptoms (presentation)³

The severity and impact of ASD varies greatly depending on age, development, and presence or absence of associated conditions.

Autistic spectrum disorder is associated with a higher functional ability than autism. People with autistic spectrum disorder usually have fewer problems with speech and are often of average or above average intelligence.

People with AS do not usually have the learning disabilities associated with autism but they may have specific learning difficulties.

AS usually causes fewer problems with speech but there may still be difficulties with understanding and processing language.

In classic autism, children tend to be spotted earlier (18-30 months) because of impaired communication. In AS, the diagnosis comes later - usually at school entry, when socialisation becomes necessary. Many people with AS may learn to mask their problems. They may present as patients with no serious mental health problem but who are anxious, are lonely, have a poor employment record and just don't seem to fit in.

Idioma

There is normal speech development before the age of 4 years, with good grammar and vocabulary. However, their tone is flat and they are pedantic. They also have a restricted repertoire of subjects. They have poor non-verbal communication skills.

They may take language very literally and be unable to interpret idiom. For example, if you use the phrase 'in a nutshell', they will be confused about how what you are saying is going to end up inside a nut.

Cognition

They are often obsessed with complex subjects and described as 'eccentric' or 'little professors'. IQ is normal - above average. They score well in verbal ability but below average in performance abilities. Patients with AS may be highly creative and have exhibited outstanding skills in mathematics, music and computer sciences. Their strength lies in concrete, rather than abstract, thinking.

They have poor powers of imagination. They lack an intuitive theory of mind (ability to imagine what others are thinking or feeling) and are often unable to talk about their own emotions, which may lead to anxiety and depression in later life.

They also lack central coherence. This is the ability to integrate individual elements of perception into an overall context of meaning, ie seeing the 'bigger picture'. The following statement could be typical of a patient with AS: "I see hundreds of individual trees but I cannot see a forest." They tend to be detail-orientated and have great difficulty understanding the overall context.

Behaviour

There are delayed motor milestones and then clumsiness. There are poor sleep patterns. They experience difficulties falling, and staying, asleep. They are more interested in others compared with people with more severe forms of autism, but do not share interests. Their interaction is one-sided. They are solitary, with no friends, and socially aware - but may display inappropriate reciprocal interaction. They may be seen as eccentric.

Problemas médicos asociados

Associated medical conditions are much less common for people with AS than for people with more severe forms of ASD.

• Epilepsy: 25-30% of children on the autistic spectrum may have seizures. This usually appears in puberty.⁶ These are more common in children who have significant cognitive problems or dysmorphic features.

• Discapacidad visual; discapacidad auditiva.

• Mental health:⁷

  • La depresión, la ansiedad y el trastorno obsesivo-compulsivo son especialmente frecuentes en adultos jóvenes con TEA.

  • Studies suggest that 30-84% of adults with ASD might have some form of diagnosable mental illness.⁸

  • Neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD) are common in adults with ASD.

  • La prevalencia de los trastornos de salud mental aumenta tanto en las personas con trastornos generales graves del aprendizaje como en las que padecen TEA.

• Discapacidad general de aprendizaje.

• Underlying medical conditions, such as untreated phenylketonuria, congenital rubella, cytomegalovirus or toxoplasmosis, fragile X syndrome or tuberous sclerosis.

• Sleep disorders are common.

Screening tools⁸

• Population screening for ASD is not recommended in the UK. False positive or false negative results from inappropriate use of screening tests may delay the correct diagnosis. The decision about the need for referral and further assessment should be made on clinical grounds.

• However, ASD-specific assessment tools may be used to supplement the process of clinical history taking - eg, the Autism Diagnostic Interview, Revised (ADI-R), the Diagnostic Interview for Social and Communication Disorders (DISCO) and the Developmental, Dimensional and Diagnostic Interview.

• The Autism Spectrum Quotient-10 instrument may be used to help identify adults with possible ASD who should be referred for further assessment.

• A negative result from an assessment does not necessarily rule out the diagnosis. If parental concerns continue, a referral is advisable.⁹

• La evaluación de niños y jóvenes con retraso en el desarrollo, problemas emocionales y de conducta, trastornos psiquiátricos, problemas de salud mental o síndromes genéticos debe incluir la vigilancia de los TEA como parte de la práctica habitual.

Diagnóstico diferencial

• Deafness.

• Discapacidad general de aprendizaje.

• Childhood disintegrative disorder (Heller's disease).

• Rett syndrome.

Making the diagnosis¹⁰

Este trastorno puede diagnosticarse de forma fiable entre los 2 y los 3 años de edad. El National Institute for Health and Care Excellence (NICE) ha publicado una guía para la evaluación y derivación de niños con sospecha de TEA:

• Es necesario un diagnóstico especializado. Probablemente, la mejor forma de realizarlo sea a través de neurólogos pediátricos, pediatras del desarrollo y del comportamiento, psiquiatras infantiles o psicólogos. Lo ideal sería contar con un equipo multidisciplinar ("el equipo TEA"), con formación específica y experiencia en la evaluación de niños con TEA.

• La participación de logopedas y terapeutas ocupacionales, educadores especiales y trabajadores sociales puede proporcionar una evaluación más detallada de ámbitos específicos.

• Other conditions need to be excluded and investigations for chromosome analysis and hearing and sight tests, are usually taken prior to reaching the diagnosis. Where clinically relevant, the following should be considered for all children and young people with ASD:

  • Examen del estado físico, con especial atención a los rasgos neurológicos y dismórficos.

  • Cariotipado y análisis del ADN del cromosoma X frágil.

  • Examen auditivo.

  • Investigaciones para descartar causas reconocidas de TEA - por ejemplo, esclerosis tuberosa.

• Las evaluaciones de niños y jóvenes por TEA no pueden ser apresuradas. Puede que no sea posible obtener pruebas suficientes en una sesión y que el niño/joven necesite ser observado en diferentes entornos, por ejemplo, en la escuela (especialmente en actividades no estructuradas como el recreo) y en la clínica.

• ASD is diagnosed when an individual exhibits six or more symptoms across the three core areas.

• Todos los niños y jóvenes con TEA deben someterse a una evaluación completa de sus capacidades de habla, lenguaje y comunicación. Esto ayudará a decidir qué intervenciones son las más adecuadas para ese niño.

Referring children and young people to the 'ASD team'¹⁰

La evaluación, el diagnóstico y la intervención precoces son muy importantes. Las indicaciones de derivación a un especialista para una evaluación adicional incluyen:

• Remitir a los niños menores de 3 años al "equipo TEA" si hay regresión en el lenguaje o las habilidades sociales.

• Derivar primero a un pediatra o neurólogo pediátrico (que puede derivar al "equipo TEA" si es necesario) a los niños y jóvenes mayores de 3 años con regresión en el lenguaje, o de cualquier edad con regresión en las habilidades motoras.

• Considere la posibilidad de remitir a los niños y jóvenes al "equipo TEA" si le preocupa un posible TEA sobre la base de los signos y/o síntomas comunicados u observados. Tenga en cuenta:

  • La gravedad y duración de los signos y/o síntomas.

  • El grado en que los signos y/o síntomas están presentes en diferentes entornos (por ejemplo, el hogar y la escuela).

  • El impacto de los signos y/o síntomas en el niño o joven y en su familia.

  • El nivel de preocupación de los padres o cuidadores y, si procede, las preocupaciones del niño o joven.

• Factores asociados a una mayor prevalencia de TEA.

• La probabilidad de un diagnóstico alternativo.

Autistic spectrum disorder treatment⁸

Prompt diagnosis and appropriate intervention, specialised educational programmes and structured support may help a person with ASD to maximise his/her potential.

Management is usually undertaken in educational settings. Local support networks may be in place for educational support in mainstream school if appropriate and will feed down from paediatrician or educational psychologist. Occupational therapy, speech therapy and physiotherapy may help specific problems.

Non-pharmacological interventions

Children and young people

• Parent-mediated interventional programmes should be considered, as they may help families interact with their child, promote development and increase parental satisfaction, empowerment and mental health.

• Behavioural and other psychological interventions:

  • Behavioural and other psychological interventions include intensive behavioural and developmental programmes aimed at improving overall functioning and altering outcome, and interventions which aim to address specific behavioural difficulties associated with ASD, such as sleep disturbance, or to increase positive behaviours such as initiating social contact with peers.

  • Behavioural therapies may be considered to address a wide range of specific behaviours, including challenging behaviours, both to reduce symptom frequency and severity and to increase the development of adaptive skills. Behavioural therapy should also be considered for children who experience sleep problems.

  • Early intensive behavioural intervention (EIBI) programmes:

    • EIBI programmes aim to engage the child with ASD in a structured learning programme that is highly individualised, taking into account the idiosyncratic motivations and specific needs of each child.

    • EIBI programmes attempt to address a comprehensive range of behaviours associated with ASD, rather than focusing on one specific aspect such as communication, social skills or interaction.

    • Programmes vary considerably in terms of technologies and emphasis but are all based on applied behaviour analysis (ABA).

    • ABA-based and intensive programmes increasingly include developmental programmes such as the Learning Experiences and Alternative Program for Preschoolers and their parents (LEAP) and the Early Start Denver Model (ESDM).

    • EIBI programmes are intensive and target a comprehensive range of skills for training, practice and generalisation.

  • Cognitive behavioural therapy (CBT) may be considered, using a group format where available and appropriate, to treat anxiety. The delivery of CBT should be adapted for people with ASD.

• Communication interventions:

  • Many children and young people with ASD have little or no speech. Those who do have speech have difficulties in using language effectively (pragmatic language impairment or social communication difficulty).

  • Many of the strategies implemented to support communication are designed and managed by speech and language therapists, working in partnership with parents.

  • Speech and language therapy is most effective when speech and language therapists also train and work with teachers, families and peers promoting functional communication in normal environments. Interventions to support communicative understanding and expression, such as the Picture Exchange Communication System and the use of environmental visual supports (eg, in the form of pictures or objects), should be considered.

  • Deben considerarse las intervenciones de apoyo a la comunicación social. Las habilidades sociales (atención, juego interactivo, respuesta a propuestas sociales e iniciación y mantenimiento de comportamientos sociales) pueden enseñarse de forma explícita.

  • When children are school-aged, social skills groups can be useful. Using videos and social stories can help to teach specific skills.

• Occupational therapy:

  • Sensory integration therapy has been used when there are marked sensory perception issues - eg, over-sensitivity to touch. Occupational therapists desensitise the child gently over time.

  • La terapia ocupacional también se centra en el desarrollo y mantenimiento de la motricidad fina y las habilidades de adaptación.

  • Children and young people affected by ASD may benefit from occupational therapy, advice and support in adapting environments, activities and routines in daily life.

• Other interventions:

  • La musicoterapia puede ayudar a mejorar las habilidades de interacción social, comunicación verbal, iniciación de conductas y reciprocidad socioemocional a corto y medio plazo.

  • Systematic reviews of complementary therapies, acupuncture and animal-assisted interventions reported that evidence for the use of complementary and alternative therapies for individuals with ASD is sparse and no strong conclusions could be drawn.

  • Advice on diet and food intake should be sought from a dietician for children and young people with ASD who display significant food selectivity and dysfunctional feeding behaviour, or who are on restricted diets that may be adversely impacting on growth, or producing physical symptoms of recognised nutritional deficiencies or intolerances.

Adultos

• Las intervenciones psicosociales pueden utilizarse para abordar una serie de resultados en adultos con TEA, incluidos los comportamientos adaptativos, la comunicación, las habilidades sociales, el empleo, la calidad de vida y las dificultades de salud mental comórbidas.

• Los programas sociales incluyen elementos de comunicación y comportamiento. La mayoría de las intervenciones psicosociales dirigidas a mejorar los resultados en adultos se han desarrollado para niños y jóvenes, y hay menos pruebas sobre su eficacia en la edad adulta.

• Psychosocial interventions should be considered for adults with ASD if indicated for managing co-existing conditions. There is insufficient evidence to recommend any specific model of psychosocial intervention. However, a diagnosis of ASD should not prevent anyone from receiving these interventions.

• Por lo tanto, si un individuo con TEA experimenta un síntoma o afección (p. ej., ansiedad) que normalmente se trataría con TCC o una intervención psicosocial relacionada, debe recibir la intervención recomendada por las directrices para ese síntoma o afección.

• Las intervenciones para mejorar la alfabetización emocional, la tolerancia a la angustia, las habilidades de relajación o la adaptación general pueden considerarse intervenciones de primera línea.

Tratamiento farmacológico

The management of ASD is essentially non-pharmacological. However, certain drugs may be considered for the management of co-existing psychiatric or neurodevelopmental conditions and may occasionally have a short-term adjunctive role in alleviating core symptoms of ASD. Any pharmacological intervention should only be undertaken by doctors with appropriate training in the care of people with ASD.

Pronóstico³

• Autism spectrum disorder (ASD) is a lifelong disorder and has a great impact on the child or young person and their family and/or carers. However, ASD varies greatly in terms of the level of impairments, which influence the prognosis.

• The presence or absence of associated learning (intellectual) disability, language impairment, and additional mental health problems are the most important prognostic factors. Unaffected language development and the absence of an associated intellectual disability are associated with a more favourable prognosis.

• The prognosis of ASD can be improved by early diagnosis and assessment because this aids understanding of why the child or young person is different from their peers.

• The lives of people with ASD and their family and/or carers can be greatly improved by early diagnosis and prompt access to:

  • Support and services in education, health services, and social care.

  • A route into voluntary organisations.

  • Contact with other children and families with similar experiences.