Table 2.
Evaluating pathways: “patient brain to caregiver health” versus “patient behavior to caregiver health”
| R2 | R2 adj | R2 change | df | RSS | RSSchange | F-statistic | p value | |
|---|---|---|---|---|---|---|---|---|
| Dependent variable: caregiver psychopathology (SCL-90) | ||||||||
| Model 1: behavior only | 0.16 | 0.10 | – | 125 | 17.15 | – | 2.93 | 0.005 |
| Model 2: behavior and brain | 0.19 | 0.13 | – | 124 | 16.51 | – | 3.22 | 0.001 |
| Model Δ | – | – | 0.03 | – | – | −0.64 | 4.79 | 0.030 |
| Dependent variable: caregiver global health (SF-36) | ||||||||
| Model 1: behavior only | 0.11 | 0.05 | – | 125 | 13.72 | – | 1.95 | 0.059 |
| Model 2: behavior and brain | 0.16 | 0.10 | – | 124 | 13.38 | – | 2.64 | 0.008 |
| Model Δ | – | – | 0.05 | – | – | −0.34 | 7.40 | 0.007 |
When patient brain volumes are added as predictors to the linear regression models predicting poor caregiver health, the explained variance is increased compared to when just patient behavioral symptoms and covariates are entered as predictors. “Behavior only” model predictors: patient behavioral symptoms (NPI) + caregiver age + caregiver sex + patient diagnosis + patient dementia severity + patient cognitive functioning + patient total intracranial volume + scanner field strength. “Behavior and brain” model predictors: (same as above) + patient brain volumes extracted from the right ventral anterior insula and superior medial frontal gyrus. RSS, residual sum of squares.