Background- The study of phenomenology in movement disorder helps to classify movement into tremor, dystonia, chorea, myoclonus etc based on the rate, rhythm, range, region involved and the manoeuvres or situations that bring out or suppress the abnormal movement. Further study of characteristics of movement can help predict etiology, eg. tic tac chorea in Syndenham’s disease, slow myoclonus in SSPE, etc. We describe characteristic upper limb dystonia as a correlate to ‘Eye of tiger’ brain MRI sign seen in Pantothenate kinase associated neurodegeneration (PKAN).

Methods- The authors examined children less than 15 years with upper limb dystonia having MRI correlate of ‘Eye of tiger’ sign and age matched controls with dystonia due to any cause and MRI not showing ‘Eye of tiger’ over a period of 2 years.

Results- 5 cases of upper limb dystonia were recognised having MRI correlate of ‘Eye of tiger’ sign. All of them had distinctive pattern of upper limb dystonia with extension at shoulder, flexion at elbow and at times pointing index finger, appearing as if it is going behind back. The dystonia was asymmetric and action induced initially, and later appeared at rest. Children also showed quasi-purposive quality of dystonia by keeping dystonic hand over the waist. Only one control group patient out of 15 examined showed the characteristic dystonia.

Conclusions- ‘Eye of Tiger sign’ in children is highly specific for PKAN. Therefore the representative upper limb dystonia is a special feature of PKAN and helps in its early and accurate diagnosis.