Head tremor and pain in cervical dystonia.

Background: Although head tremor (HT) and pain are prevalent in cervical dystonia (CD), their joint relationship to phenotypic features of focal dystonia remains unclear.

Objectives: We examined how severity of HT and pain are associated with age of CD onset and duration, and whether HT subtypes ("jerky" or "regular") exhibit distinct relationships between severity of HT and pain.

Methods: The severity of HT and pain were assessed with the Toronto Western Spasmodic Torticollis Rating Scale in retrospective review of 188 CD patients recruited through the Dystonia Coalition.

Results: HT severity was associated with longer CD duration (p < 0.0005), whereas pain severity was associated with younger age at onset (p = 0.043). HT severity and pain severity were not correlated for jerky HT (p = 0.996), but positively correlated for regular HT (p = 0.01).

Conclusions: The distinct associations of HT and pain with age at onset, disease duration, and HT subtype further characterize the heterogeneity of CD's clinical presentation and suggest similarly heterogeneous underlying mechanisms.