Children with phenylketonuria treated early: basic audiological and electrophysiological evaluation

Area of Science:

• Neuroscience
• Audiology
• Genetics

Background:

• Phenylketonuria (PKU) is a genetic disorder often associated with cognitive deficits, including executive function and attention impairments.
• These deficits are presumed to stem from deficient neurotransmitter synthesis, even with early diagnosis and treatment.
• The impact of PKU on auditory pathways, particularly in early-treated individuals, requires further investigation.

Purpose of the Study:

• To examine the peripheral and central auditory pathways in children with early-treated PKU.
• To compare auditory pathway function between children with adequate versus inadequate dietary control for PKU.
• To compare auditory function in children with PKU to age-matched controls without PKU.

Main Methods:

• Utilized basic audiological and electrophysiological evaluations, including pure-tone and speech audiometry, immittance testing, and auditory brainstem and middle latency responses.
• Compared 25 children with early-treated PKU (subdivided by diet adequacy) against 35 age-matched controls.
• Analyzed demographic and audiological data using analysis of variance with repeated measures.

Main Results:

• Audiometric evaluations were largely within normal limits, with one exception of mild conductive hearing loss in the inadequate diet group.
• Children with inadequate diets (Group B) showed poorer speech discrimination and higher 4000 Hz stapedial reflex thresholds.
• Auditory brainstem responses indicated longer latencies in Group B, and both PKU groups exhibited longer interpeak interval I-V compared to controls.

Conclusions:

• Early-treated PKU may affect the pontine auditory pathway, independent of dietary adherence.
• Observed differences, though small, suggest a need for auditory processing assessments in children with PKU.
• Monitoring auditory function can help evaluate the functional implications of PKU on auditory pathways.