Abstract
We studied the pattern-reversal VEP, the BAEP and the EEG with conventional and computerized
analysis in 41 adolescents with hyperphenylalaninemia (24 HPA type 1,12 HPA type 2,
4 HPA type 3, 1 DHPR deficiency) and 35 control persons. A prolongation of the P100
latency in the VEP, a greater interear difference of the I-V interwave latency in
the BAEP and slowing of EEG background activity were found. Five per cent of the patients
demonstrated spikes and 12.5 % abnormal sharp transients in the EEG. The latency increase
in the VEP corresponded to the compliance with the diet during the first decade of
life. No influence of the actual Phe concentration at the time of the investigation
was demonstrated. The BAEP- and EEG-findings were not related to the course of treatment.
Thus the VEP changes in this cross sectional study refer to alterations of brain function
that occurred during the early years of life. To investigate the value of evoked potentials
and EEG in monitoring brain function after discontinuing the diet longitudinal data
are needed.
Key words
Phenylketonuria - Hyperphenylalaninemia - Adolescents - Evoked potentials - EEG
