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Pattern-reversal visual evoked potentials in phenylketonuric children
1Institute of Neurosurgery, University of Milan, Padiglione Beretta Ovest, Italy.
Insights
Pattern-reversal visual evoked potentials (PR-VEPs) are more sensitive than EEG for detecting neurophysiological issues in phenylketonuria (PKU) children. Early diet and good metabolic control correlate with normal PR-VEPs, while high phenylalanine levels and delayed treatment show abnormalities.
Area of Science:
- Neuroscience
- Pediatrics
- Metabolic Disorders
Background:
- Phenylketonuria (PKU) is a genetic disorder requiring strict low-phenylalanine (phe) diet.
- Neurophysiological derangements can occur in PKU despite dietary management.
- Early detection and monitoring of neurological function are crucial for PKU patients.
Purpose of the Study:
- To evaluate the sensitivity of pattern-reversal visual evoked potentials (PR-VEPs) compared to EEG in detecting neurophysiological abnormalities in PKU children.
- To correlate neurophysiological findings with metabolic parameters, including phenylalanine levels and timing of dietary intervention.
Main Methods:
- Recording of pattern-reversal visual evoked potentials (PR-VEPs) and electroencephalography (EEG) in 14 PKU children on a low-phe diet.
- Correlation of neurophysiological data with plasma phenylalanine levels (current, mean, and at diet initiation).
- Assessment of the impact of metabolic control and age at diet start on neurophysiological test results.
Main Results:
- PR-VEPs identified neurophysiological derangements in 6 out of 14 PKU children, whereas EEG identified abnormalities in only 3.
- No significant alterations were found in neurophysiological tests among children with good metabolic control.
- Children with high mean phenylalanine levels (>10 mg/100 ml) or delayed diet initiation (after 2 months) showed a higher prevalence of pathological PR-VEPs.
Conclusions:
- PR-VEPs are more sensitive than EEG for detecting subclinical neurophysiological abnormalities in PKU.
- Good metabolic control and early dietary intervention are associated with normal neurophysiological function in PKU patients.
- Elevated phenylalanine levels and delayed treatment initiation negatively impact neurophysiological outcomes in PKU, as indicated by PR-VEP abnormalities.
Abstract:
Pattern-reversal visual evoked potentials (PR-VEPs) and EEG were recorded in 14 phenylketonuric (PKU) children on a low-phenylalanine (phe) diet; the data obtained were correlated with metabolic parameters, namely, the actual phe plasma level, the mean phe plasma level in the last year, an the beginning of the diet. PR-VEPs seem to be more sensitive than EEG in detecting neurophysiological derangements in these subjects; in fact PR-VEPs were pathological in six patients while EEG detected three; no significant alterations were found in the neurophysiological tests among the children with good metabolic control, and only one child was abnormal among the six on an early dietetic regimen; in contrast, six of the nine subjects presenting with high mean phe plasma levels (greater than 10 mg/100 ml) and five of the eight whose diet started after the 2nd month of life showed pathological PR-VEPs.