Abstract
Patients with cervical dystonia (CD) often believe that disease severity would have progressed beyond the pre-treatment level if botulinum neurotoxin (BoNT) therapy had not been initiated. The aim of the present study was to assess the perceptions of long-term BoNT-treated patients with CD regarding the expected course of disease severity over the next 10 years under the hypothetical assumption that BoNT therapy is discontinued. Fifty patients with idiopathic CD receiving long-term BoNT therapy were screened, and 43 patients were included. Disease severity at the day of recruitment was assessed as a percentage of CD severity at the onset of BoNT therapy (PAS-%). Patients also generated, in a standardized manner, a graph illustrating the development of CD severity since initiation of BoNT therapy. Subsequently, patients estimated the expected severity of CD after 10 years, expressed as a percentage of severity at BoNT therapy onset (PAS-STD), under the hypothetical assumption that BoNT therapy was discontinued at the time of recruitment. They additionally drew a graph depicting the anticipated progression of CD severity over the subsequent 10 years under this assumption. Furthermore, 33 of these 43 patients had previously assessed the expected development of CD severity under the assumption that no BoNT therapy had ever been performed (PAS-NO%) in an earlier study. Mean PAS-STD was significantly higher than mean PAS-% (p < 0.001). Comparison of mean PAS-STD with mean PAS-NO% in the 33 patients who participated in both studies demonstrated that mean PAS-STD was significantly lower than mean PAS-NO% (p < 0.001). Long-term BoNT-treated patients with CD believe that disease severity would worsen again if BoNT therapy were discontinued. However, they do not expect CD severity to deteriorate to the level that they believe would have been reached if no BoNT therapy had been administered. We interpret this finding as suggesting that patients perceive a preventive effect of long-term BoNT therapy.