Cervical dystonia is characterized by abnormal posturing of the head, often combined with tremor-like oscillatory head movements. The nature and source of these oscillatory head movements is controversial, so they were quantified to delineate their characteristics and develop a hypothetical model for their genesis. A magnetic search coil system was used to measure head movements in 14 subjects with cervical dystonia. Two distinct types of oscillatory head movements were detected for most subjects, even when they were not clinically evident. One type had a relatively large amplitude and jerky irregular pattern, and the other had smaller amplitude with a more regular and sinusoidal pattern. The kinematic properties of these two types of oscillatory head movements were distinct, although both were often combined in the same subject. Both had features suggestive of a defect in a central neural integrator. The combination of different types of oscillatory head movements in cervical dystonia helps to clarify some of the current debates regarding whether they should be considered as manifestations of dystonia or tremor and provides novel insights into their potential pathogenesis.
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Giovanni Defazio;
Mark Hallett;
Hyder Jinnah;
Glenn T. Stebbins;
Angelo F. Gigante;
Gina Ferrazzano;
Antonella Conte;
Giovanni Fabbrini;
Alfredo Berardelli
Existing scales for rating the severity of blepharospasm (BSP) are limited by a number of potential drawbacks. We therefore developed and validated a novel scale for rating the severity of BSP. The development of the scale started with careful examination of the clinical spectrum of the condition by a panel of experts who selected phenomenological aspects thought to be relevant to disease severity. Thereafter, selected items were first checked for reliability, then reliable items were combined to generate the scale, and clinimetric properties of the scale were evaluated. Finally, the confidence with which the scale could be used by people without high levels of movement disorders skill was assessed. The new scale, based on objective criteria, yielded moderate to almost perfect reliability, acceptable internal consistency, satisfactory scaling assumptions, lack of floor and ceiling effects, partial correlations with a prior severity scale and with a quality of life scale, and good sensitivity to change. Despite a few limitations, the foregoing features make the novel scale more suitable than existing scales to assess the severity of BSP in natural history and pathophysiologic studies as well as in clinical trials.
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C. L. Comella;
J.S. Perlmutter;
Hyder Jinnah;
T. A. Waliczek;
A. R. Rosen;
W. R. Galpern;
C. A. Adler;
R. L. Barbano;
Stewart Factor;
C. G. Goetz;
J. Jankovic;
S. G. Reich;
R. L. Rodriguez;
W. L. Severt;
M. Zurowski;
S. H. Fox;
G. T. Stebbins
Introduction: The aim of this study was to test the clinimetric properties of the Comprehensive Cervical Dystonia Rating Scale. This is a modular scale with modifications of the Toronto Western Spasmodic Torticollis Rating Scale (composed of three subscales assessing motor severity, disability, and pain) now referred to as the revised Toronto Western Spasmodic Torticollis Scale-2; a newly developed psychiatric screening instrument; and the Cervical Dystonia Impact Profile-58 as a quality of life measure. Methods: Ten dystonia experts rated subjects with cervical dystonia using the comprehensive scale. Clinimetric techniques assessed each module of the scale for reliability, item correlation, and factor structure. Results: There were 208 cervical dystonia patients (73% women; age, 59±10 years; duration, 15±12 years). Internal consistency of the motor severity subscale was acceptable (Cronbach's alpha=0.57). Item to total correlations showed that elimination of items with low correlations (<0.20) increased alpha to 0.71. Internal consistency estimates for the subscales for disability and pain were 0.88 and 0.95, respectively. The psychiatric screening scale had a Cronbach's alpha of 0.84 and satisfactory item to total correlations. When the subscales of the Toronto Western Spasmodic Torticollis Scale-2 were combined with the psychiatric screening scale, Cronbach's alpha was 0.88, and construct validity assessment demonstrated four rational factors: motor; disability; pain; and psychiatric disorders. The Cervical Dystonia Impact Profile-58 had an alpha of 0.98 and its construction was validated through a confirmatory factor analysis. Conclusions: The modules of the Comprehensive Cervical Dystonia Rating Scale are internally consistent with a logical factor structure.
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Alberto Albanese;
Kailash Bhatia;
Mahlon R DeLong;
Stanley Fahn;
Victor S.C. Fung;
Mark Hallett;
Joseph Jankovic;
Hyder A Jinnah;
Jonathan W. Mink;
Jan K. Teller