Difficulties in recruiting

Background: Several studies have indicated that infants who had undergone postnatal painful procedures appear to be hypersensitive to pain, with a lower threshold to tactile stimulations later on life.

Objective: To study the effect of early exposure to pain on cerebral somatosensory evoked potential (SEP) response to thermal stimulation (550C), in preterm and full term born adolescents (15-18 years old), who have undergone painful procedures during their neonatal period. As well as to study the effect of early exposure to thermal and tactile sensory thresholds and pain thresholds to thermal and tactile stimuli, by using the TSA and von Frey hairs.

Design: Case-control study.

Participants: Four groups of 20 adolescents (aged 15-18 years), two of which are full term and preterm-born who were exposed to painful procedures during the neonatal period. The other two groups are term and preterm-born adolescents who were not exposed to such procedures.

Main Outcome Measures: Cerebral SEP response (P300, Medoc Ltd., Israel) to thermal stimulation (550C). Warm-sensation threshold (WST), heat-pain threshold (HPT), Cold sensation threshold (CST) and cold pain threshold (CPT) by using Thermal sensory analyzer (TSA-2001,Medoc Ltd., Israel). Pain threshold to tactile stimulation will be measured by using Von-Frey hairs.

Inclusion Criteria:

For all:

• Age 15-18
• Appropriate weight for gestational age (AGA)
• Informed consent signed by the parent
• Presence of one parent during the examination

Premature groups:

• Preterm-born (32-34 weeks of gestation)
• Admitted to the NICU (ventilated vs. non-ventilated)

Full term groups:

• Completed 37 weeks of gestation Pain groups (premature and full term)
• Admitted to the NICU
• Mechanically-ventilated during the first week of life
• Mechanically-ventilated for at least 48 hours

Exclusion Criteria:

• Current use of analgesia
• A chronic illness with current medical treatment
• Cognitive impairment

Four groups of 20 adolescents (aged 14 years or older), two of which are full term and preterm-born who were exposed to painful procedures during the neonatal period. The other two groups are term and preterm-born adolescents who were not exposed to such procedures.