Clinical Research Directory

Inclusion criteria: * Infants aged 2 to 6 weeks post-term in corrected age at the first assessment. * Born at or after 32 weeks' gestational age. * No known neurological or gastrointestinal disease. * Written informed consent from the holder(s) of parental authority. * Meeting the criteria for one of the following two cohorts: * Excessive-crying (EC) cohort: crying for more than 3 hours per day on at least 3 consecutive days during the 7 days preceding the assessment (modified Wessel criteria), together with at least two of the following three protocol-specified Rome IV-related features: crying without an apparent cause, inconsolable crying, and associated signs including agitation, facial flushing, clenched fists, and/or flexed legs. * Typical-crying (TC) cohort: crying for less than 2 hours per day during the week preceding the assessment. Infants crying for 2 to 3 hours per day during the week preceding the assessment will not be included in either cohort. Exclusion criteria: * Confirmed cerebral lesions identified by ultrasound or magnetic resonance imaging. * Major congenital or chromosomal abnormalities. * Growth faltering. * Birth before 32 weeks' gestational age. * Holder(s) of parental authority who do not speak French. * Lack of written informed consent from the holder(s) of parental authority. * Lack of affiliation with a French social security scheme. * Any situation falling under specific legal protection provisions under French law.