Reversal of hypertonic co‐contraction after bilateral pallidal stimulation in generalised dystonia: A clinical and electromyogram case study

Abstract

In a patient of generalised dystonia treated with bilateral pallidal stimulation, serial surface EMGs recorded from the neck muscles during alternating head movements revealed progressive reduction in hypertonic activity and reversal of co-contraction to reciprocal contraction, which preceded clinical improvement.

Current and emerging strategies for treatment of childhood dystonia

“…Although co-contraction is normally identified as a feature of dystonia, 34,35 co-contraction is not necessary for the maintenance of stable postures, either for voluntary postures or for dystonic postures. Co-contraction may not be as frequently present in children with dystonia as originally thought, 36 and in some cases co-contraction could represent voluntary compensation.…”

A dominant bursting electromyograph pattern in dystonic conditions predicts an early response to pallidal stimulation

“…Although resolution of co-contraction may anticipate and correlate with improvement, 21 the results of the present study suggest that other factors must also be influenced by the effects of DBS on pallidal circuitry. In our experience, the facilitation of movement secondary to relief of painful muscular spasms is often the first noticeable improvement to occur after surgery.…”

“…In particular, there are very few cases where EMGs have been employed to determine treatment or to demonstrate improvements following intervention. 21 One possible reason is that the various forms of dystonic activity described above are often superimposed in the compound EMGs. This complicates the differentiation of the symptom-specific activity from other forms of muscular activity expressed, consequently causing difficulty in monitoring any changes brought about by therapeutic intervention.…”

Extracting burst and tonic components from surface electromyograms in dystonia using adaptive wavelet shrinkage

“…In this report, we have demonstrated two additional examples to our previous reports (Liu et al, 2004;Wang et al, 2003) of potential implications in the study of the surface EMGs in patients with dystonia. One is to differentially separate the superimposed bursting and tonic activity, which enables us to study the functional relationship between those two components.…”

“…3). Also, EMG recording shows other dystonic features such as co-contraction between the antagonist muscles and 'overflow' between neighbouring muscles (Berardelli et al, 1998;Liu et al, 2004).…”