Downs Syndrome Flashcards
Genetics of Downs Syndrome
3rd chromosome 21 is present from the moment of conception. This is called a genetic trisomy. Result of a random mutation, rather than Down syndrome being inherited.
Prevalence of Down syndrome against mother’s age
Age 30: less than 1 in 1000, age 35: 1 in 400, age 42: 1 in 60.
3 types of Down syndrome
- Standard Trisomy 21
- Translocation (4%)
- Mosaicism (2%)
Standard Trisomy 21
Every cell has the 3rd chromosome 21
Translocation
The extra 21st chromosome is attached to another chromosome
Mosaicism
Only some of the cells have an extra 21st chromosome
Is Downs syndrome inherited?
Most cases are not inherited (sporadic)
Downs Syndrome can be traced through families in less than 1% of people with the condition
It is very unusual for parents to have more than one child with Downs Syndrome
Physical Phenotype of Downs syndrome
Phenotypic dysmorphic facial features found in 100% of affected individuals.
Identified by distinctive facial features and low muscle tone and loose joints
Medical phenotype of Downs syndrome
- Sucking and feeding problems
- Congenital heart defects
- Hearing and vision deficits
- Respiratory problems
Chapman and Hesketh (2000)
Verbal skills were strong with those with Downs (along with social functioning, self-help and daily living skills). Speech, language, verbal processing and motor functioning were weaknesses
Lott and Dierssen (2010)
- Frontal lobe – Reduced volume and larger minicolumns with fewer cells
- Temporal lobe – Reduced volume, reduced number of cells, and altered microarchitecture of pyramid cells
- Basal ganglia – Normal
- Parietal lobe – Normal volume and altered microarchitecture of pyramid cells
- Hippocampal system – Altered microarchitecture of pyramid cells
- Basal prosencephalon – Early cholinergic degeneration
- Amygdala – Normal
- Cerebellum – Hypoplasia and reduced number of granule cells
- Brainstem – Altered serotoninergic, noradrenergic, and cholinergic systems
Godfrey and Lee (2018)
Found impairments in Long Term Memory from school-age onwards. Deficits in both verbal and non-verbal working memory. Impairments got greater with age.
Impairments in verbal short term memory from school age and beyond. However, small effect size and mixed findings for non-verbal STM.
Impairments in verbal working memory from adolescence and beyond. Mixed findings for non verbal.
Lanfranchi et al (2010)
Examined executive function s in Down syndrome.
Miyake et al (2000)
Proposed that there are three main functions; Shifting, Inhibition, and Updating of working memory
Loveall (2017)
Impairments in executive functions across the lifespan. There were also changes in functioning across the lifespan
Martin et al (2009)
Pattern observed in Down Syndrome
* Phonological errors in speech production
* Poor speech intelligibility
* Receptive vocabulary/ comprehension unaffected
* Expressive vocabulary acquisition is delayed
* Syntax/ grammatical structure presents a particular challenge
* Some differences in pragmatics
Cebula et al (2010)
Social cognition of those with Downs Syndrome
* Subtle differences in early attention e.g. slow to develop mutual gaze
* Fewer spontaneous gestures
* Difficulty in social referencing
* Difficulty in recognising emotions/ facial expressions of others
Behaviour of those with Downs syndrome
They are perceived as cheerful, charming, affectionate and sociable. They show more positive facial expressions than TD people. Low risk of psychopathology compared to other ND people. They are prone to social distraction and have high rates of externalising behaviours.
Dykens et al (2002)
Found evidence for behavioural difficulties and changes in behaviour across development
Lifespan of Downs syndrome
In the 1940s, the average life expectancy for individuals with DS was 12 years
With medical breakthroughs and improvements in services, individuals with DS now enjoy life expectancies into their 60s
Premature aging
At 35, many Downs syndrome people develop neuropathic changes similar to Alzheimers. There may be memory loss and changes to personality and behaviour.
Down syndrome and dementia
Around 30% of people with DS are affected by dementia
Interventions for Downs syndrome
- Physical features- Physical therapy
- Language- Speech and language therapy
- Behaviour- Emotional and behavioural therapies
- Ageing- Drug treatments and support services for ageing / dementia
- Early intervention
- Support for the family
Neil and Jones (2018)
Conducted a systematic review of communication interventions for individuals with Downs Syndrome
* They concluded that favourable effects come from behaviour analytic approaches
* Important features are intensity of interventions e.g. frequency of sessions and opportunities to practice
Hardee and Fetters (2017)
Conducted a review of exercise interventions in those with Downs Syndrome
* They concluded that there are many positive outcomes e.g. for balance, endurance strength, but also daily life activities and wellbeing
* Interventions included cardio-vascular training, strength training, swimming, and even judo
