Page 286 - Demo

Chapter 9284power due to the principle of multiple crossing-overs.21,22 They address the question of variability in treatment response. If we want to move towards patient-centered care for rare disorders, we should individualize treatment interventions and outcomes in research designs. N-of-1 studies are especially appropriate in chronic conditions with stable symptoms and when the treatment has a relatively rapid onset (to minimize burden regarding trial duration) and allows an offset with a short half-life (to limit carryover effects).23 However, the N-of-1 design may be less suitable for certain indications and treatments. For example, for antidepressants and antipsychotics it may take a considerable amount of time before effects become evident. Also, withdrawal effects of the medication can disrupt the findings. Hence, other SCEDs may be recommended in specific situations.24 The choice for a design may depend, for example, on:y Type of intervention (e.g., behavioral, symptomatic, diseasemodifying);y The natural course of the construct the intervention is expected to target;y Time required to enable measuring an effect;y The ‘reversibility’ of the effect when an intervention is withdrawn;y The number of available individuals to participate. N-of-1 design(Withdrawal /Reversal design)MultiplebaselinedesignAlternatingtreatmentsdesignChangingcriteriondesignBi-phasic A-B design1-phase design (Bphase training study)Pre-postinterventionCasedescriptionSingle-case methodologySingle-caseexperimental designRandomizedFigure 1. Trial designs especially applicable to rare and heterogeneous patient populations, including single-case experimental designs (SCEDs). Figure adapted from Tate et al. (2013).Annelieke Muller sHL.indd 284 14-11-2023 09:08