Speech and Language Delays in AADC

Emily Malcolm, PhD avatar

by Emily Malcolm, PhD |

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Caring for a child with a developmental disorder such as aromatic L-amino acid decarboxylase (AADC) deficiency can be challenging, with parents and caregivers having to deal with issues such as speech and language delays.

Speech and language delays in children

When children experience speech and language delays, they are not developing speech and language at the expected normal rate. Speech is the expression of language — the way that sounds and words are formed by the mouth, tongue, and throat. Language refers to understanding and being understood through verbal or non-verbal communication.

While every child is different, children normally reach specific levels of speaking milestones: many infants babble even before their first birthdays, and toddlers might know about 20 words by the time they are 18 months old.

Children with language delays might be able to pronounce words correctly but have difficulty putting words together to form phrases. Those with speech delays might understand phrasing, but have difficulty pronouncing words.

Verbal delays in AADC deficiency

Many children with AADC deficiency are non-verbal. They may not babble as infants, and take longer to form their first words. Most symptoms get worse towards the end of the day but improve after sleep.

Speaking is controlled by the coordination of the muscles of the throat, tongue, and mouth, and this coordination is impaired in people with AADC deficiency.

What to do about speech and language delays

Speech therapists can show patients some exercises to strengthen their muscles and build coordination to improve their verbal skills. They can also help patients and their caregivers develop communication strategies that rely less on verbal communication, such as sign language, for example.


Last updated: Oct. 23, 2019


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