At the end of the inclusion period, the observed correlations were much lower than expected. Thus, it did not seem relevant to prolong the inclusions.

The purpose of this study is to correlate the composite PIPP-R (Premature Infant Pain Profile-Revised) scale and the parasympathetic nervous system (heart rate variability).

The premature newborns hospitalized for several weeks are exposed to a significant number of nursing procedures or painful or stressful medical. Repeated pain in the neonatal period may have negative consequences in the short and / or long term. The diagnosis of pain remains difficult because based on the hetero-assessment involving the use of validated scales. The PIPP-R scale (Premature Infant Pain Profile-Revised) appears to be the most complete and best validated scale as composite (behavior items, vegetative and contextual). However, it is rarely used in routine care in France.

Alternatives to clinical scoring the pain level were described, in particular the analysis of the variability of the heart rate [VHR] by HFVI index (High Frequency Variability Index) or skin conductance. The analysis of the spectral components of high frequencies or HFVI would be an indicator of parasympathetic activity. The HFVI was compared to the EDIN scale, purely behavioral level, proposed as chronic pain marker. Skin conductance would be a stress marker reflecting variations of the sympathetic system.

These techniques are currently marketed for routine use. However, these methods have been compared and the NIPE (Newborn Infant parasympathetic Evaluation), which assesses the HFVI index, was not compared to a validated scale procedural acute pain (such as PIPP-R).

It seems important, before disseminating these methods, explore the consistency of these techniques with each other and validated scales, and their acceptability by nurses.

Inclusion Criteria:

• Newborns with gestational age less than 36 weeks
• Hospitalization in neonatology unit or intensive care unit
• Signature of major parental consent for participation of their child

Exclusion Criteria:

• Brain injury (intraventricular haemorrhage> Grade 2 or peri- ventricular leukomalacia extended)
• Administration of anticholinergic or adrenergic antagonist in the previous 48 hours
• Administration of curares
• Genetic abnormality or severe malformation

All collected data that underlie results in a publication

Data will be available after the publication of result and ending fifteen years following the last visit of the last patient

Data access requests will be reviewed by the internal committee of Brest UH. Requestors will be required to sign and complete a data access agreement.