[Electroencephalogram evaluation of hyperphenylalaninemia patients on dietetic treatments]

To explore the electroencephalographic changes of patients with hyperphenylalaninemia (HPA) after dietetic treatments.

From July 2005 to February 2010, 34 HPA patients with abnormal electroencephalograms were recruited from China-Japan Friendship Hospital. Their electroencephalographic results and clinical features were compared before and after dietetic and antiepileptic treatments. There were 16 males and 18 females with an age range of 2 months to 8 years. All electroencephalographic results were abnormal. Among them, there were epileptic discharges (n = 17), atypical sharp-slow wave complex (n = 1) and slow wave background (n = 16). All patients received a low intake of phenylalanine at 13-50 mg·kg(-1)·d(-1). Twenty patients had antiepileptic drug therapy. Before and after treatment for 3 months, 6 months, 1 year and 2 years, blood phenylalanine concentration, electroencephalogram, convulsion and other clinical parameters were observed. Before and after 1 year treatment, the tests of developmental quotient (DQ) or intelligence quotient (IQ) were performed.

The phenylalanine concentrations of the same patient group decreased significantly after 3 months, 6 months, 1 and 2 years after dietetic treatment ( (0.51 ± 0.39) , (0.50 ± 0.29), (0.59 ± 0.42), (0.53 ± 0.27) vs (1.33 ± 0.64) mmol/L, all P = 0.000). Among 19 epileptic cases, 16 ceased after treatment. And 14 stayed convulsion-free within 3 months post-treatments, 2 cases had intermittent tonic-clonic seizures while there was 1 case of focal seizures. Fourteen cases withdrew antiepileptic medications or reduced their doses. After treatment, the electroencephalographic results became totally normal in 8 of the 19 epileptic cases. Electroencephalographic results improved in 5 cases versus pre-treatment. Spikes were controlled in 10 cases including 5 patients with hyperarrhythmia in the abnormal electroencephalographic group with epilepsy. Six cases continued abnormal electroencephalogram. In the abnormal electroencephalographic group without epilepsy (n = 15) , electroencephalograms were normal (n = 3), improved (n = 6) and continued mild abnormal waves (n = 2). However, there were 4 cases with deteriorated electroencephalogram and 3 of them showed spikes. DQ (IQ) was evaluated in 16 cases. And variable mental retardation was observed in all of them. After, year treatment, 7 cases were evaluated DQ (IQ), and their results showed improved (57 ± 16 vs 50 ± 16, t = -5.42, P = 0.002).

Etiological treatment for HPA patients is important for controlling epilepsy and improving brain function. And electroencephalogram is useful for monitoring brain functions and evaluating treatment outcomes.