5.2.1 Pain measurement: during the study phase acute pain will be measured once a day during a heel prick by a validated algometric scale for acute pain (PIPP); chronic pain will be measured 3 times a day by a validated algometric scale for chronic pain (EDIN). Inter-rater reliability has been shown acceptable for both scales (26,27). Moreover, in October 2006 the Coordinating Center organized a theoretical and practical course on the correct application of the PIPP and EDIN scales (26,27) for all the participating centers in order to reduce the inter-Center variability in pain measurement.