Table 4.

Multiple regression analysis with VIQ, PIQ, FIQ

		Estimate	Std. Error	t value	Pr( >|t|)
VIQ	NfL	-0.31557	0.01130	-27.922	< 0.001***	P < 0.001
	Minimum SaO2	0.24777	0.04707	5.264	< 0.001***	Adjusted R2 = 0.9602
	RAI	-0.89795	0.18802	-4.776	< 0.001***	F = 836.6
PIQ	NfL	-0.35853	0.02625	-13.658	< 0.001***	P < 0.001
	Age	1.04610	0.09327	11.216	< 0.001***	Adjusted R2 = 0.9216
	Father’s education level	0.85349	0.12742	6.698	< 0.001***	F = 204.6
	Tonsil size	-1.69374	0.23067	-7.343	< 0.001***
	Minimum SaO2	0.03552	0.09932	0.358	0.721
	RAI	-0.45600	0.16713	-2.728	< 0.01**
FIQ	NfL	-0.25107	0.02531	-9.921	< 0.001***	P < 0.001
	Age	1.18906	0.06821	17.432	< 0.001***	Adjusted R2 = 0.9769
	Course of choking	-0.07922	0.02250	-3.520	< 0.001***	F = 879.2
	Maternal education level	0.84824	0.22024	3.851	< 0.001***
	Tonsil size	-2.59813	0.39786	-7.063	< 0.001***

Nfl Neurofilament light, SaO₂ Arterial oxygen saturation, RAI Respiratory arousal index, VIQ Verbal IQ, PIQ Performance IQ, FIQ Full-Scale IQ. The education level:1: completed primary school; 2: completed part secondary education; 3: completed secondary education; 4: completed postsecondary training; 5: completed an undergraduate university degree; 6: completed a postgraduate university degree. Tonsil size: Grade 0, tonsils restricted into the tonsil fossae; Grade 1, tonsils sitting just outside of the tonsillar fossa and occupying ≤ 25% of the area between the tonsillar pillars; Grade 2, tonsils seen in the airway and occupying 25–50% of the area between the pillars; Grade 3, tonsils occupying 50–75% of the area between the pillars; and grade 4, tonsils occupying > 75% of the area between the pillars. ***P < 0.001, **P < 0.01, *P < 0.05