A series of 2 x 2 repeated measures analyses of variance (ANOVAs) were conducted with time (pre--versus postinjury) and rater (self [patient] versus other) as the grouping factors and the raw scores on the eight KBCI scales as dependent measures.
An alternative method of assessing patient's awareness problems post-TBI is examining discrepancies between self--and other ratings across KBCI scales.
To explore the concurrent validity of the two approaches for assessing post-TBI awareness problems, we examined the correlations between the GDSs and the postinjury KBCI unawareness scale.
As can be seen in Table 2, the positive correlation between self-ratings on the KBCI unawareness scale and months postinjury indicates that within this sample of individuals with moderate to severe TBI, patients reported greater problems on the unawareness scale as time postinjury increased (r = 0.33).
To address these issues, we conducted three sets of analyses: (1) concordance patterns of self-other ratings, (2) frequency of unawareness subgroups defined by KBCI normative data, and (3) uniformity of unawareness of problems in subgroups across different types of behavioral domains (e.g., executive problems, interpersonal interactions, and adjustment concerns).
Self-other discrepancy ratings were calculated for each of the eight KBCI scales for both pre--and postinjury functioning.
Those patients whose self-ratings suggested intact awareness (according to normative comparisons on the KBCI unawareness scale, i.e., within 1 SD of the normative mean) and whose other ratings also suggested awareness were identified as the "aware per both" subgroup (n = 14, 39% of sample).
A mixed model ANOVA was conducted for each KBCI scale (except unawareness, which defined the subgroups).
Follow-up t-tests of simple main effects on these four KBCI scales revealed that self--versus other ratings did not differ in either the aware per both or the unaware per both subgroups for either pre--or postinjury ratings.
Two additional KBCI scales showed similar threeway interaction patterns (Figure 2) and approached statistical significance: emotional adjustment (p = 0.07) and impulsivity (p = 0.09).
Each of the eight KBCI scales was significantly elevated postinjury compared with preinjury.
The pattern of correlations between injury severity and time postinjury with self--versus other ratings on the KBCI unawareness scale suggests that as time postinjury increases, individuals with TBI become more accurate in their awareness ratings.