Effect of botulinum toxin type-A treatment on non-motor symptoms and cognitive functions in patients with isolated adult-onset cervical dystonia

[Speaker] Maja Relja:1
[Co-author] Vladimir Miletic:1
1:Department of Neurology, Medical School, University of Zagreb, Croatia

Objective: To investigate the effect of botulinum toxin type-A (BTX-A) on non-motor symptoms (NMS) and cognitive functions in patients with isolated adult-onset cervical dystonia (IAOCD).
Background: It is well known that BTX-A improve motor function in patients with IAOCD. However, NMS are increasingly recognized as a part of IOACD phenotype. But NMS and cognitive functions in IAOCD were rarely investigated during BTX-A treatment.
Design/Methods: We studied 51 IAOCD drug nave patients before and after BTX-A therapy. Severity of motor symptoms, disability, and pain were assessed with Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). Psychiatric assessment included quantitative questionnaires: Beck Depression Inventory; Second Edition (BDI-II), Beck Anxiety Inventory (BAI), Starkstein Apathy Scale (AS). Sleep quality and fatigue were determined with Pitsburgh Sleep Quality Index (PSQI) and Fatigue Severity Scale (FSS). Cognitive functions were assessed using Cogtest: a computerized neurocognitive battery set of 5 tests examining several cognitive domains: Auditory Number Sequencing (ANS), Spatial Working Memory (SWM), Strategic Target Detection (STD), Continuous Performance Test- Flanker version (Flanker CPT) and Tower of London (ToL). Assessment was performed at baseline (before BTX-A injections) and 4 months after injections.
Results: Mean BDI-II score, BAI score and AS score did not change significantly 4 months after BTX-A treatment (dose 150-200 U of botulinum toxin type A as Botox or Xeomin) (p>0.05). BTX-A treatment had no significant effect on mean PSQI and FSS score as well as on any of cognitive functions assessed (p<0.05). Significant pain amelioration (p<0.001), unrelated to improvement of motor symtoms, was observed after BTX-A application.
Conclusion: Spectrum of IAOCD symptoms includes psychiatric co morbidities, impaired sleep quality, fatigue and cognitive dysfunction, especially in domains of attentions and executive functioning, thus implicating shared neurobiology of motor and NMS. In addition to improvement of motor symptoms of IAOCD patients, BoNT-A was significantly effective in reducing pain, but ineffective in reducing anxiety, depression and fatigue or sleep quality and apathy. There was no impact on cognitive functions during this short term treatment. But long-term follow up of BoNT-A therapy is needed for final conclusions.

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