Table 8.

Multiple regression results. In these analyses, narrative accuracy and diversity PCs were used to predict Structured Test PC2, which reflected differences in performance between argument structure and verb morphology.

All PPA	β	SE	t	p
Intercept	0.000	0.096	<0.001	1.000
Narr. Accuracy PC2	−0.003	0.179	−0.018	0.986
Narr. Accuracy PC1	0.122	0.073	1.673	0.099
Narr. Diversity PC2	0.026	0.112	0.236	0.814
Narr. Diversity PC1	0.068	0.087	0.781	0.438
Narr. Accuracy PC2 * Narr. Accuracy PC1	−0.247	0.085	−2.896	0.005
Narr. Diversity PC2 * Narr. Diversity PC1	0.148	0.079	1.875	0.065
13 PPA with severe agrammatism (Narr. Accuracy PC1 < −1.2)
Intercept	−0.589	0.201	−2.936	0.014
Narr. Accuracy PC2	0.691	0.156	4.419	0.001
64 PPA with mild or no grammatical impairments (Narr. Accuracy PC1 > −1.2)
Intercept	0.107	0.108	0.988	0.327
Narr. Accuracy PC2	0.039	0.182	0.215	0.831

Note: β = beta-weight (estimate of co-efficient); SE = standard error.