Affiliations: [a] Newcastle Regional Sleep Service, Newcastle upon Tyne Hospitals NHS Trust, NE7 7DN, UK
| [b] Institute of Genetic Medicine, The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
Correspondence to: Sophie D. West, Newcastle Regional Sleep Service, Newcastle upon Tyne Hospitals NHS Trust, NE7 7DN, UK. Tel.: +44 191 233 6161; Fax: +44 191 2137397; E-mail: [email protected].
Abstract: Objective: We conducted prospective assessments in people with myotonic dystrophy type 1 (DM1) with daytime sleepiness, provided targeted therapies and assessed response. Methods: Patients had overnight sleep assessments. Treatment with continuous positive airway pressure (CPAP) for OSA, non-invasive ventilation (NIV) for respiratory failure, modafinil for excessive daytime sleepiness were commenced. Results: 120 people were studied: mean age 46.9 years (SD 13.2, range 18–74), body mass index 27.9 kg/m2 (7.2, 16–53), Epworth Sleepiness Score (ESS) 13.1 (4.7, 2–24). Twenty one people (18% of group) had OSA: mean age 49.6, BMI 31.1, ESS 14.3, ODI 22, pO2 11.3, pCO2 5.4. All were offered CPAP; seven continued with benefit but 14 had intolerance or no benefit. Thirty-three people (27%) had respiratory failure and abnormal sleep study: mean age 51.5, BMI 31.3, ESS 13.9, ODI 22.9, pO2 8.7, pCO2 6.8. All were offered NIV; 12 continued with benefit but 18 had intolerance or no benefit, 1 died and 2 declined commencement. Thirty-six people (30%) had predominantly sleepiness: mean age 44.8, BMI 24.6, ESS 14.1, ODI 9.2, pO2 11.7, pCO2 5.4. All were offered modafinil; 12 continued this with benefit but 10 had intolerance or no benefit, one was unkeen to start, 11 did not attend further clinic and two had other sleep disorders. Comparing means of treatment responders to non-responders showed no significant difference in any variable, except ESS: 15.9 vs.11.9 respectively, p < 0.0001. Conclusions: Causes of sleepiness are variable in DM1, but include obstructive sleep apnoea, respiratory failure and sleepiness with a normal sleep study; 29% of this studied cohort benefited from targeted sleep therapies.