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dystonia_treatment

Dystonia treatment

Treatment must be highly customized to the needs of the individual and may include oral medications, botulinum neurotoxin injections, physical therapy and/or other supportive therapies, and/or surgical procedures such as deep brain stimulation.

Surgery

Pallidal Deep Brain Stimulation is the primary surgical treatment.

However, evidence from case series or uncontrolled study suggests that it may lead in some patients to specific parkinsonian symptoms such as freezing of gait, micrographia, and bradykinesia.

Mahlknecht et al. investigated parkinsonian signs using the Movement Disorder Society Unified Parkinson Disease Rating Scale by means of observer-blinded video ratings in a group of 29 patients treated with pallidal Deep Brain Stimulation and a non-surgical control group of 22 patients, both with predominant cervical dystonia. Additional assessments included MRI-based models of volume of neural tissue activated to investigate areas of stimulation related to dystonic symptom control and those likely to induce parkinsonian signs as well as an EMG analysis to investigate functional vicinity of stimulation fields to the pyramidal tract. Compared with controls, stimulated patients had significantly higher motor scores (median, 25th-75th percentile: 14.0, 8.0-19.5 versus 3.0, 2.0-8.0; P < 0.0001), as well as bradykinesia (8.0, 6.0-14.0 versus 2.0, 0.0-3.0; P < 0.0001) and axial motor subscores (2.0, 1.0-4.0 versus 0.0, 0.0-1.0; P = 0.0002), while rigidity and tremor subscores were not different between groups. Parkinsonian signs were partially reversible upon switching stimulation off for a median of 90 min in a subset of 19 patients tolerating this condition. Furthermore, the stimulation group reported more features of freezing of gait on a questionnaire basis. Quality of life was better in stimulated patients compared with control patients, but parkinsonian signs were negatively associated with quality of life. In the descriptive imaging analysis maximum efficacy for dystonia improvement projected to the posteroventrolateral internal pallidum with overlapping clusters driving severity of bradykinesia and axial motor symptoms. The severities of parkinsonian signs were not correlated with functional vicinity to the pyramidal tract as assessed by EMG. In conclusion, parkinsonian signs, particularly bradykinesia and axial motor signs, due to pallidal stimulation in dystonic patients are frequent and negatively impact on motor functioning and quality of life. Therefore, patients with pallidal stimulation should be monitored closely for such signs both in clinical routine and future clinical trials. Spread of current outside the internal pallidum is an unlikely explanation for this phenomenon, which seems to be caused by stimulation of neural elements within the stimulation target volume 1).


Surgery, such as the denervation of selected muscles, may also provide some relief; however, the destruction of nerves in the limbs or brain is not reversible and should be considered only in the most extreme cases.

The procedure of deep brain stimulation (DBS) has proven successful in a number of cases of severe generalised dystonia.

Deep brain stimulation (DBS) has been used to treat various neurological and psychiatric disorders. Over the years, the most suitable surgical candidates and targets for some of these conditions have been characterized and the benefits of DBS well demonstrated in double-blinded randomized trials.

1)
Mahlknecht P, Georgiev D, Akram H, Brugger F, Vinke S, Zrinzo L, Hariz M, Bhatia KP, Hariz GM, Willeit P, Rothwell JC, Foltynie T, Limousin P. Parkinsonian signs in patients with cervical dystonia treated with pallidal deep brain stimulation. Brain. 2018 Aug 24. doi: 10.1093/brain/awy217. [Epub ahead of print] PubMed PMID: 30165511.
dystonia_treatment.txt · Last modified: 2018/08/31 10:58 by administrador