Prise en charge par thérapie cognitivo-comportementale d'une insomnie chronique comorbide d'une maladie de Parkinson : protocole expérimental d'observation d'un cas unique

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease. For years, PD has been traditionally defined through motor symptomatology, but it is now recognized that the non-motor symptoms affecting neuropsychiatric, sleep, autonomic, and sensory domains occur in up to 88% of PD patients, probably resulting in a significant source of disability. In a community-based cross-sectional study, nearly two-thirds of patients with PD presented nighttime sleeping problems and chronic insomnia was reported among one-third of patients (Gjerstad et al., 2007). This rate is three times higher than in the general population. According to the American Academy of Sleep Medicine, cognitive-behavioral therapy for insomnia (CBT-i) is the optimal recommendation for the treatment of chronic insomnia, independent of comorbities associated or non-associated with insomnia. In fact, numerous studies have documented the efficiency of CBT-i in the treatment of chronic insomnia comorbid with a wide spectrum of psychiatric, neurological, oncological and algological problems (Geiger-Brown et al., 2015). Furthermore, it is important to emphasize that CBT is applicable and efficient in the treatment of several problems frequently associated with PD, such as anxiety, depression and impulsive-compulsive disorders. To our knowledge, there is no specific data relating to the use of CBT in chronic insomnia comorbid with PD. In this context, the general objective of this study was to look at the efficiency of CBT-i in the treatment of chronic insomnia comorbid with PD, in an experimental, single-case study. This efficiency was assessed both by short interval measures (i.e. consensus sleep diary) and by longer interval measures (i.e. self-assessment questionnaires). The latter concerned complaints of insomnia as well as dysfunctional thoughts and attitudes about sleep. The patient was a 62-year-old man who was diagnosed with PD at the age of 59. Two years after diagnosis, insomnia developed. The patient's predominant daily complaint concerned dissatisfaction with both sleep quantity and quality, associated with difficulty falling sleep, and difficulty staying asleep with inability to fall back to sleep. Insomnia was associated with excessive daytime sleepiness and depressive symptoms. CBT-i treatment was carried out over six sessions in accordance with the interventional protocol suggested by Morin (Morin & Espie, 2003). Psychoeducation treated sleep functioning and insomnia; sleep restriction consisted in limiting the number of hours spent in bed to the number of real hours of sleep; stimulus control involved instructions aimed at reinforcing the association between sleep and temporal and contextual indices; cognitive restructuration was centred around dysfunctional beliefs related to sleep; education on sleep hygiene included the teaching of good sleeping habits. Finally, three post-therapeutic evaluations (at two weeks, one month and three months) were carried out by an independent assessor and included the completion of a sleep calendar as well as different clinical evaluation scales. The results of the visual analysis confirmed by Wilcoxon signed-rank tests, as well as the temporal series analysis show a signification reduction in the total awakening time (−72%, Z = −3.23, P = 0.001), as well as a significant increase in sleep efficiency (+16%, Z = −3.17, P = 0.002) between the baseline and post-therapy stage. These improvements in sleep were maintained at one and three month follow-ups. The average efficiency of sleep increased significantly between the baseline and one-month follow-up (+19%, Z = −3.29, P = 0.001) as well as between the baseline and three-month follow-up (+21%, Z = −3.29, P = 0.001). At the three-month follow-up the patient no longer met the diagnostic criteria of chronic insomnia (DSM-V). Improvement in sleep was accompanied by improvement in mood, in daytime drowsiness, in insomnia indices such as the insomnia severity index, in dysfunctional beliefs and attitudes about sleep and in the state of cognitive and somatic activation prior to going to bed. This single-case study demonstrates the feasibility and potential benefit of CBT for insomnia comorbid with PD while providing important information necessary to design more definitive studies in the future.