Table 3.
Final selection of relevant papers: strength of correlation between altered insight assessment and neuroimaging metrics, and main findings.
| Paper | Strength of correlation between altered insight assessment and neuroimaging metrics | Study findings | |||
|---|---|---|---|---|---|
| Statistical analyses; Coefficient used | Threshold | Threshold cluster extent where applicable | p value used for interpretation | ||
| Mendez and Shapira (2005) | Factorial analysis of variance (ANOVA), F-test | Not specified | Not applicable (visual inspection) | p < 0.001 for main effect; p < 0.01 for right-left hemispheres and frontal-temporal lobes effects; not significant interaction (however, right frontal predominance) | Loss of insight in FTD was associated with hypoperfusion/hypometabolism in the right hemisphere, especially in the frontal lobes. |
| Miller et al. (1997) | X2 | Not specified | Not applicable (visual inspection) | p = 0.04 | Patients with FTD showed an early loss of personal awareness related to uneven frontotemporal dysfunctions, either bilateral or unilateral |
| McMurtray et al. (2006) | Ordinal regression; F and Bonferroni tests | p < 0.005 | Not applicable (visual inspection) | p < 0.001 | Loss of insight into behavioural change was associated with right frontal hypoperfusion |
| Levy et al. (2018) | Regression; R2 | Not specified | Not specified | R2 = =0.45 for self-regulation mask | - Outcomes from measures of clinical judgement were more robust than patient-informant DS when correlating with brain structures. - Altered global insight correlated with left OFC and right rostral ACC in the whole cohort of patients (bvFTD, CBS and PPA). - Episodic memory functioning did not predict altered insight. |
| Ichikawa et al. (2013) | Two-tailed Fisher correlation | p < 0.05 | N/A (areas of horns measured in mm2) | p = 0.0016 for anterior horn; p < 0.0001 for inferior horn | - Significant positive correlations between anosognosia scores and increase of anterior and inferior horns sizes (indexes of frontotemporal atrophy) in ALS, but especially ALS with FTLD. - Longitudinal increases of horn sizes were significantly more rapid in non-demented ALS patients compared with controls. - The anosognosia score was predominantly correlated with longitudinal enlargement of the inferior horn size (index of medial temporal lobes atrophy) in non-demented ALS patients. |
| Hornberger et al. (2014) | Voxel-wise general linear model; Covariate only model; T-contrast | Significant clusters formed by TCE method (5000 permutations); p < 0.001, FDR corrected for each voxel | 20 voxels | p < 0.001 | - Scores on insight into Diagnosis and treatment and Language domains did not differ among groups and were not covaried with GM volumes. -Whole group (bvFTD, SD, PNFA, AD and LA) significant correlations were found between GM volumes and insight into social interactions, emotion processing, and motivation/organization, but not on dementia subgroup analysis. -Social interactions insight correlated with left OFC, left PHPC, right MTG, bilateral insula, and right AMG atrophy. - Emotion processing insight correlated with bilateral FP cortices, right DLPC, supplementary motor area, bilateral ACC, and left AMG atrophy. - Motivation insight covaried with bilateral OFC, left ACC, right FP cortical atrophy. - Overall insight covaried with bilateral OFC and right FP cortical atrophy. |
| Massimo et al. (2013) | Regression | p < 0.05 FDR corrected for both voxel and cluster level analyses | 15 voxels | p < 0.05 | Impaired capacity to self-appraise cognitive performances correlated with GM density across ventral and rostral medial prefrontal regions in AD and bvFTD and especially with the subgenual cingulate (BA 25) in bvFTD. |
| Rosen et al. (2010) | Covariates only model | p < 0.05 corrected for MC using FWE correction | 25 voxels | p < 0.05 | Altered self-appraisal correlated with tissue content mainly in the right ventromedial prefrontal cortex in the whole cohort (behavioural and language variants of FTD, CBD, ALS, MCI, AD and HC). |
| Shany-Ur et al. (2014) | General linear models; T-test | p < 0.05 FWE corrected | Study specific T-threshold at p < 0.05 after 1000 permutations | p < 0.05 | - Whole group analysis (behavioural and language variants of FTD, AD and HC). Participants were split into under- and over-estimators. - Overestimating ADL competency correlated with atrophy of widespread right frontal regions, anterior insula, putamen, thalamus, medial & lateral temporal lobes & pons. - Overestimating cognitive functioning was associated with atrophy of right middle frontal & middle temporal gyri. - Overestimating emotional control correlated with atrophy in bilateral OFC, insula and right SFG. - Overestimating interpersonal abilities was linked with atrophy of putamen and fusiform gyrus. - Overestimating overall functioning was associated with atrophy of right orbital inferior frontal gyrus, middle frontal gyrus, caudate head, and putamen, left superior frontal gyrus, and the pons. |
| Sollberger at al. (2014) | Multiple regression design (covariates only); T-test | p < 0.001 voxel-wise | p < 0.001 corrected for MC at p < 0.05 based on cluster extent and a custom-fit error distribution determined by 1000 permutations | p < 0.001 uncorrected | - Overestimation of empathic concern correlated with GM volumes in right-hemispheric anterior inferolateral temporal regions in the whole cohort of participants behavioural and language variants of FTD, AD, AD, CBS y HC). - bvFTD and nfPPA mostly overestimated their empathic concern compared to HC. |
| Ruby et al. (2007) | Behavioural-metabolic correlation analyses; Z-scores | p < 0.05 corrected at cluster level | 315 voxels | p < 0.05 | - Decreased metabolic activity in the left temporal pole correlated with reduced insight into behavioural change in bvFTD group - Reduced insight into personality changes did not exhibit significant neural correlates |
| Bastin et al. (2012) | Factorial analysis | p<0.05 FWE corrected for MC at the voxel level | 20 voxels | p < 0.05 | bvFTD patients with reduced autonoetic consciousness exhibited hypometabolism across the anterior medial prefrontal cortex, the left dorsolateral prefrontal cortex (near the superior frontal sulcus), parietal regions, and the posterior cingulate cortex. |
| Zamboni et al. (2010) | Full factorial model; One tailed T-test | p < 0.001 uncorrected | 1568 voxels | p < 0.001 uncorrected; p < 0.05 FWE corrected and FDR | - Combined cohort (behavioural and language variants of FTD, CBS and HC) showed correlations between reduced insight into behavioural change and GM loss in a region extending from the right superior temporal sulcus to the right ITG (posterior region of the right superior temporal sulcus, adjacent to the temporoparietal junction). - bvFTD patients underestimated their current behavioural disturbances and overestimated their premorbid ones. |
| Amanzio et al. (2016) | Explorative univariate linear regression | p < 0.005 corrected for MC; statistical inferences made according to RFT | 150 voxels; small clusters filtered with a p FWE corrected>0.05 (Ke> FWE corrected) | p < 0.001 | bvFTD patients exhibited significant correlations between decreased awareness of performance on iADL and regional GM volume changes in the MPFC (predominantly MCC, dorsal anterior insula and cuneous) and areas of the anterior and posterior cerebellum. |
| García-Cordero et al. (2016) | Multiple regressions; T-tests and Spearman correlations | Structural and functional analysis: p > 0.001 uncorrected; lesion analysis: p < 0.05 | 50 voxels in structural analysis and 10 voxels in functional analysis | p < 0.05 or p < 0.001 |
Correlations between interoceptive awareness & structural MRI: - Combined bvFTD, AD & HC groups: IFG, STG, temporal pole, ACC, AMG, HPC and PHPC. - bvFTD group alone: temporal and parietal cortices plus the MCC, PHPC and AMG. Correlations between interoceptive awareness & resting state MRI: - Combined bvFTD, AD & HC group: IFG, HPC and PHPC. - bvFTD group alone: inferior, middle and superior frontal gyri including the prefrontal cortex. |