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. 2024 Jun 15;47(9):zsae109. doi: 10.1093/sleep/zsae109

Table 4.

Best Fit Mixed-Effects Models Comparing PIPR by Diagnostic Group and Season Including PLR and Estimated Retinal Irradiance in Response to Red and Blue Stimuli

Coefficient SE 95% CI P AIC
Model 3 −161.63
 Intercept 0.022 0.071 [−0.120 −0.164] .757
 Group 0.094 0.038 [0.018 −.169] .016*
 Season 0.096 0.040 [0.016 −.176] .020*
 Group*season −0.206 0.075 [−0.357 to −0.055] .008**
−0.084 0.039 [−0.163 to -.005] .037*
 TT 0.129 0.072 [−0.016 to 0.273] .079
 PLRred(mm) −0.013 0.012 [−0.037 to 0.011] .283
Model 7 −157.57
 Intercept 0.013 0.069 [−0.127 to 0.152] .856
 Group 0.091 0.038 [0.015 to 0.168] .020*
 Season 0.093 0.040 [0.012 to 0.174] .025*
 Group*season −0.200 0.076 [−0.354 to −0.047] .011*
−0.081 0.040 [−0.161 to −0.001] .049*
 TT 0.137 0.074 [−0.012 to 0.286] .071
 PLRblue(mm) −0.013 0.011 [−0.035 to 0.010] .266
Model 11 −165.86
 Intercept 3.581 1.56 [0.448 6.713] .026*
 Group 0.079 0.037 [0.006.153] .036*
 Season 0.089 0.038 [0.012.166] .024*
 Group*season −0.182 0.073 [−0.329 to 0.035] .016*
−0.069 0.039 [−0.146.009] .082
 TT 0.161 0.072 [0.016.305] .030*
 ret-iradred −0.237 0.103 [−0.444 to 0.030] .025*
Model 12 −166.80
 Intercept 1.797 1.079 [−0.365 to 3.960] .101
 Group 0.092 0.037 [0.018 to 0.167] .016*
 Season 0.101 0.039 [0.023 to 0.179] .013*
 Group*season −0.209 0.074 [−0.357 to 0.060] .007**
−0.084 0.039 [−0.162 to 0.007] .034*
 TT 0.126 0.071 [−0.017 to .270] .083
 ret-iradblue −0.118 0.070 [−0.259 to 0.023] .100

These four models were less than 10 AIC points different from one another, and significantly improved compared to the next best models. Coefficient estimates represent unstandardized beta coefficients. SE, standard error. AIC, Aikaike’s Information Criterion (lower values reflect better model fit (larger negative values), and improvement is significant when a given model is 2 or more units lower). 95% CI is the 95% Confidence Interval for the coefficient. *p < .05, **p < .01, ***p < .001. PLRred is the pupil light reflex after the red stimuli, respectively. TT, testing time, PLRred(mm) is expressed in millimeters. ret-iradblue and ret-iradred are calculated retinal irradiance values based on calculations reported in text in units of log Photons/cm2/s. See supplementary materials for all mixed-effects model results.