Background: Neuroimaging studies examining upper limb somatosensory deficits are scarce. 
 Aim: To investigate functional connectivity at rest associated with upper limb somatosensory impairments in the early phase post-stroke. 
 Methods: We recruited 20 stroke patients within 4-7 days post stroke with an upper limb somatosensory deficit, and 12 healthy controls. Six network indexes of functional connectivity at rest were created; cortical and subcortical interhemispheric, ipsilesional cortical and subcortical intrahemispheric and contralesional cortical and subcortical intrahemispheric index. General Linear Models were used to investigate group differences; patients with mild to moderate versus severe impaired somatosensory function versus healthy controls, for each somatosensory modality of the Erasmus-modified Nottingham sensory assessment. Covariates age, center and mean framewise displacement were included as nuisance regressors. 
 Results: 
Significant altered connectivity was found in severe compared to mild to moderately affected patients and to healthy controls with higher connectivity values for severe exteroceptive somatosensory impairments for the cortical interhemispheric index (p<0.05), and lower connectivity values for the contralesional subcortical intrahemispheric index (p<0.05). Additionally, a main effect of exteroception, proprioception and sensory discrimination based on subscores of the Erasmus-modified Nottigham Sensory Assessment was found for the index of cortical interhemispheric (p<0.05), contralesional subcortical intrahemispheric (p<0.05) and ipsilesional cortical intrahemispheric (p<0.05) functional connectivity. 
Conclusion: Patients with severe somatosensory impairments show significant lower functional connectivity at rest in both cortical and subcortical networks inter- as well as intrahemispherically. Different rehabilitation approaches may be needed for patients with severe compared to patients with mild to moderate somatosensory impairments.

INTER- AND INTRAHEMISPHERIC CORTICAL AND SUBCORTICAL FUNCTIONAL CONNECTIVITY AT REST IS REDUCED IN PATIENTS WITH MORE SEVERE UPPER LIMB SOMATOSENSORY IMPAIRMENTS