A working knowledge of the key features is helpful in understanding FASD diagnoses and conditions, and each is reviewed with attention to similarities and differences across the four diagnostic systems. More than 400 problems, however, can occur with FASD. Growth
In terms of FASD, growth deficiency is defined as significantly below average height, weight or both due to prenatal alcohol exposure and can be assessed at any point in the lifespan. Growth measurements must be adjusted for parental height, gestational age (for a premature infant), and other postnatal insults (e.g., poor nutrition), although birth height and weight are the preferred measurements. Deficiencies are documented when height or weight falls at or below the 10th percentile of standardized growth charts appropriate to the population. Prenatal or postnatal presentation of growth deficits can occur, but are most often postnatal.Criteria for FASD are least specific in the Institute of Medicine (IOM) diagnostic system ("low birth weight..., decelerating weight not due to nutrition..., [or] disproportional low weight to height" p. 4 of executive summary), while the CDC and Canadian guidelines use the 10th percentile as a cut-off to determine growth deficiency. The "4-Digit Diagnostic Code" allows for mid-range gradations in growth deficiency (between the 3rd and 10th percentiles) and severe growth deficiency at or below the 3rd percentile. Growth deficiency (at severe, moderate, or mild levels) contributes to diagnoses of FAS and pFAS, but not ARND or static encephalopathy.Growth deficiency is ranked as follows by the "4-Digit Diagnostic Code":
Severe: Height and weight at or below the 3rd percentile.
Narrow and closed at rest, it opens during swallowing and yawning, controlled by the tensor veli palatini and the levator veli palatini (muscles of the soft palate). Children with a cleft palate have difficulties controlling these muscles and thus are unable to open the Eustachian tube. Secretions accumulate in the middle ear when the tube remains dysfunctional over a long period of time, which cause hearing loss and middle ear infections. Ultimately, hearing loss can lead to impaired speech and language development. Causes
The general term for disorders of the velopharyngeal valve is velopharyngeal dysfunction (VPD). It includes three subterms: velopharyngeal insufficiency, velopharyngeal inadequacy, and velopharyngeal mislearning. Velopharyngeal insufficiency can be caused by an anatomical abnormality of the throat. It occurs in children with a history of cleft palate or submucous cleft, who have short or otherwise abnormal vela. Velopharyngeal insufficiency can also occur after adenoidectomy. Velopharyngeal incompetence is a defective closure of the velopharyngeal valve due to its lack of speed and precision. It is caused by a neurologic disorder or injury (e.g. cerebral palsy or traumatic brain injury). Sometimes children present no abnormalities yet still have hypernasal speech: this can be due to velopharyngeal mislearning, indicating that the child has been imitating or has never learned how to use the valve correctly. Diagnosis
There are several methods for diagnosing hypernasality. A speech therapist listens to and records the child while analysing perceptual speech. In hypernasality, the child cannot produce oral sounds (vowels and consonants) correctly. Only the nasal sounds can be correctly produced.