Table 5.

Loss of standard score points in relation to 100 μmol/L increase in mean Phe and loss of standard score points in relation to 100 μmol/L increase in SD Phe after controlling for points lost in relation to mean Phe.

Time Period	Matrix Reasoning		n-back # nonresponses		n-back # responses		Go/No-Go errors
	Mean Phe	SD Phe	Mean Phe	SD Phe	Mean Phe	SD Phe	Mean Phe	SD Phe
Lifetime	--- nc ---		--- nc ---		3.2	ns	--- nc ---
< 5 yrs.	--- nc ---		--- nc ---		4.4	ns	--- nc ---
5.0 – 9.9 yrs.	--- nc ---		2.4	8.4	--- nc ---		2.4	ns
≥ 10 yrs.	2.0	6.2	2.0	ns	--- nc ---		3.1	ns

Note: nc = analysis not conducted due to lack of significant correlation between cognitive performance and mean Phe in earlier analyses; ns = not significant; IQ and Vocabulary are not included in the table because neither had significant correlations with mean Phe.