ABSTRACT
OBJECTIVE: Alice in Wonderland syndrome (AIWS) profoundly affects human perception of size and scale, particularly regarding one's own body and the environment. Its neuroanatomical basis has remained elusive, partly because brain lesions causing AIWS can occur in different brain regions. Here, we aimed to determine if brain lesions causing AIWS map to a distributed brain network. METHODS: A retrospective case-control study analyzing 37 cases of lesion-induced AIWS identified through systematic literature review was conducted. Using resting-state functional connectome data from 1,000 healthy individuals, the whole-brain connections of each lesion were estimated and contrasted with those from a control dataset comprising 1,073 lesions associated with 25 other neuropsychiatric syndromes. Additionally, connectivity findings from lesion-induced AIWS cases were compared with functional neuroimaging results from 5 non-lesional AIWS cases. RESULTS: AIWS-associated lesions were located in various brain regions with minimal overlap (≤33%). However, the majority of lesions (≥85%) demonstrated shared connectivity to the right extrastriate body area, known to be selectively activated by viewing body part images, and the inferior parietal cortex, involved in size and scale judgements. This pattern was uniquely characteristic of AIWS when compared with other neuropsychiatric disorders (family-wise error-corrected p < 0.05) and consistent with functional neuroimaging observations in AIWS due to nonlesional causes (median correlation r = 0.56, interquartile range 0.24). INTERPRETATION: AIWS-related perceptual distortions map to one common brain network, encompassing regions critical for body representation and size-scale processing. These findings lend insight into the neuroanatomical localization of higher-order perceptual functions, and may inform future therapeutic strategies for perceptual disorders. ANN NEUROL 2024.
ABSTRACT
BACKGROUND AND OBJECTIVES: Scrupulosity, despite its considerable prevalence and morbidity, remains under-investigated. The present study develops and examines the psychometric properties of a comprehensive assessment tool, the Scrupulosity Inventory (SI). METHODS: The SI, along with other measures of obsessive-compulsive disorder (OCD) and perfectionism, were administered to a sample (N = 150) of college undergraduates similar in size to other scale development studies of related measures. We conducted exploratory and confirmatory factor analyses of the SI, examined its convergent and divergent validity, and assessed its ability to predict categorical diagnoses of scrupulosity using a receiver operator characteristic analysis. RESULTS: We found a well-fitting confirmatory bifactor model (RMSEA = 0.049) with a strong general Scrupulosity factor ( [Formula: see text] ) and specific factors for Personal Violations ( [Formula: see text] ), Ritualized Behavior ( [Formula: see text] ), Interference with Life ( [Formula: see text] ), and Problem Pervasiveness ( [Formula: see text] ). As predicted, we also found the strongest convergence (r = 0.63) between the SI and the Penn Inventory of Scrupulosity (PIOS), intermediate convergence (r = 0.54) between the SI and Perfectionism Inventory (PI), and weaker convergence (r = 0.47) between the SI and YBOCS. Finally, we found that a categorical diagnosis of scrupulosity was highly predicted by the SI (AUC = 0.84), less well-predicted by the PIOS (AUC = 0.75) and less well predicted by the YBOCS (AUC = 0.69). LIMITATIONS: This study was conducted among a sample of undergraduates at a religiously affiliated university. CONCLUSIONS: These results suggest utility in using the SI to measure the severity of scrupulosity symptoms and that scrupulosity and OCD may present significantly different clinical features.
