Dystonia is defined as a syndrome of sustained contractions , frequently causing twisting and repetitive movements or abnormal postures. Limb, axial and cranial voluntary muscles can all be affected by dystonia . The involuntary movements are often exacerbated during voluntary movements , so - called action dystonia . If the dystonic contractions appear only with specific action , it is referred to as task specific dystonia (e.g. writer's cramp)
. Moreover, voluntary movement in the normal parts in the body can induce dystonic movements , so- called overflow (Fahn and Bressman , 2000) .
Dystonia can severely affect the lives of those afflicted with the disease . Throughout history , several theories have been proposed regarding its etiology and pathophysiology , from underlying mental disorders to postinfectious to altered basal ganglia and brain stem function. However , dystonia remains poorly understood so treatment remains symptomatic and begins with medications and progresses to consideration of surgery (
Edwards et al , 1995 ) .
Most of the drugs that have been used to treat focal dystonias are beneficial in only a minority of cases . Because of this , symptomatic surgical treatments involving rhisotomy , peripheral nerve section or muscle section have been employed , with variable benefit and significant morbidity
( Gelb et al , 1989 ) . In the last decade, injections of botulinum toxin ( BT ) into the contracting muscle(s) have been shown to provide effective relief for most patients ( Jankovic et al , 1990 ) .

Injection of BT has been becoming an accepted treatment for focal dystonia . It is designed to produce enough muscle weakness to eliminate the abnormal contractions while preserving normal function ( Moore and
Blumhardt , 1991 and Edward , 2002 ) . The only drawback to BT therapy is the need for repeated injections at few months intervals . The majority of patients reported that the first injection appear to produce a more striking effect than subsequent ones ( Lees et al , 1992 ) .
A small number of patients may not have a response to BT injections ( primary non
– responders ) and others experience a loss of response to it after one or two injections ( secondary non
– responders ) . Secondary non – responsiveness is attributed to the development of antibodies to BT i.e. immunoresistance . This development correlates with earlier age at onset of dystonia , higher mean BT dose per visit , higher cumulative BT dose and giving doses too frequently ( Blackie and Lees , 1990 and Adler , 2000 ) .
Dressler ( 2000 ) reported that the interval between injection series should be at least 2 months to avoid excessive stimulation of immune system with consecutive risk of BT antibody formation .
Stell et al ( 1988 ) found that temporary side effects were encountered in their study as a result of BT injection such as dysphagia (most common), dysphonia , transient dryness of the throat and localized pain and tenderness at injection sites .
Bhatia et al ( 1999 ) postulated that some patients had developed transient generalized weakness after receiving therapeutic doses of BT for cervical and hemidystonia . The cause was most likely presynaptic inhibition due to systemic spread of the toxin .

To minimize the development of BT antibodies and to avoid BT side effects as much as possible , one should think about a complementary treatment in addition to BT injections . The aim of this treatment is to prolong the time interval between successive injections .
Are physical therapy modalities effective in keeping the overactive injected muscles inhibited as long as possible in patients with focal cervical dystonia ?
The aim of this study was to analyze and discuss the effects of transcutaneous electrical nerve stimulation ( TENS ) and prolonged stretch in patients with cervical dystonia who were treated with BT .
The results of this study might add to the clinical intervention of physical therapy in cases of focal dystonia and consequently minimize the need for repeated injections thus leading to optimization of BT benefits . Moreover , the cost for these BT injections would be minimized .
*Thirty adult patients with focal cervical dystonia .
*Patients with primary dystonia were included .

*No other pathology was affecting the involved part other than dystonia (e.g. cervical spondylosis ) .
Psychological condition of the patients could not be controlled that stress and anxiety induce the dystonic symptoms .
Physical therapy intervention might improve the symptoms in dystonic patients when applied in the time interval between successive BT injections.