Original Article Sleep patterns over 15-day period in rats with spinal cord injury

Study design: Experimental, controlled trial. Objectives: The purpose of this study was to evaluate over a 15-day period alterations in sleep pattern of rats after spinal cord injury (SCI). Setting: Federal University of São Paulo, Department of Psychobiology. Methods: In total, 20 male Wistar rats were used. The rats were divided in two groups: SHAM and SCI. The rats were submitted to the following procedures: electrode insertion surgery, 24 h duration baseline sleep recording, SCI (level T9) and subsequent sleep recording for 15 consecutive days. Results: The results showed a reduction in sleep efficiency in the light period for Days 1–3, 5, 10 and 12 after SCI in relation to the SHAM group, with alterations in total waking time and sleep stages. Limb movements were observed 4 days after SCI. Conclusion: The present findings suggest that SCI may be heavily involved in altering sleep pattern in SCI subjects and that the inactivity caused by SCI may be exacerbating this altered sleep pattern. Sponsorship: Associação Fundo de Incentivo à Psicofarmacologia (AFIP), FAPESP (03/ 06297–3, and CEPID 98/143033) and CNPQ. Spinal Cord advance online publication, 29 August 2006; doi:10.1038/sj.sc.3101971