AbstractBackgroundResearch on posterior cortical atrophy (PCA) has concentrated on cognitive decline, especially visual processing deficits. However, few studies have focused on the activities of daily living (ADL), and no study has investigated the neurometabolic basis of ADL impairments. We aimed to identify regions of hypometabolism associated with ADL in PCA patients.MethodTwenty‐nine PCA patients, 35 typical Alzheimer’s disease (tAD) patients, and 26 healthy volunteers were recruited. Each subject completed a scale for total ADL [TADL, including basic ADL (BADL) and instrumental ADL (IADL) subscales] and 18F fluorodeoxyglucose positron emission tomography. Voxel‐wise multivariable regression analysis was conducted at the level of the whole‐brain, PCA‐related hypometabolism patterns, and PCA‐specific hypometabolism patterns.ResultThe general cognitive status of PCA patients was similar to tAD patients; however, they performed worse in TADL, BADL, and IADL. In all analysis levels, TADL was associated with the bilateral parietal lobe, including the right superior parietal lobe, right inferior parietal cortex, right angular gyrus, and left superior parietal lobe. BADL was associated with the bilateral parietal lobe located in the right superior parietal lobe, right inferior parietal cortex, and left superior parietal lobe. IADL was associated with the bilateral superior parietal lobe. Bilateral superior parietal lobe hypometabolism was associated with TADL, BADL, and IADL.ConclusionHypo‐metabolism in the bilateral superior parietal lobes contributes to the decline of ADL in PCA, which is a promising target for future non‐invasive neuromodulation interventions.