Sensory symptoms in cranial dystonia: a potential role in the etiology?

Cranial dystonia is normally considered as a pure movement disorder. Sensory symptoms have not received much attention, but we found ill-defined pain, discomfort, distortion of sensory modalities, 'phantom' kinetic or postural sensations in the orofacial areas subsequently involved by the dyskinesia in all of 11 consecutive patients, preceding by weeks or months the motor syndrome. Physicians were often mislead, initially making diagnoses such as trigeminal neuralgia, dental problems, sicca syndrome, chronic conjunctivitis, glossitis or stomatitis. The patients reported that the orofacial movements were at first willingly performed in order to decrease the discomfort which was felt in these facial areas before the movements finally escaped voluntary control and became socially disturbing. We suspect that the sensory symptoms, for which no objective substrate could be found, and which were always reported before and in the exact location of the subsequent dyskinesia, could be the earliest manifestation of an evolving process in cranial and perhaps other focal dystonias.