BACKGROUND: The thalamus has a central role in the pathophysiology of idiopathic cervical dystonia (iCD); however, the nature of alterations occurring within this structure remain largely elusive. Using a structural magnetic resonance imaging (MRI) approach, we examined whether abnormalities differ across thalamic subregions/nuclei in patients with iCD.
METHODS: Structural MRI data were collected from 37 patients with iCD and 37 healthy controls (HCs). Automatic parcellation of 25 thalamic nuclei in each hemisphere was performed based on the FreeSurfer program. Differences in thalamic nuclei volumes between groups and their relationships with clinical information were analysed in patients with iCD.
RESULTS: Compared to HCs, a significant reduction in thalamic nuclei volume primarily in central medial, centromedian, lateral geniculate, medial geniculate, medial ventral, paracentral, parafascicular, paratenial, and ventromedial nuclei was found in patients with iCD (P < 0.05, false discovery rate corrected). However, no statistically significant correlations were observed between altered thalamic nuclei volumes and clinical characteristics in iCD group.
CONCLUSIONS: This study highlights the neurobiological mechanisms of iCD related to thalamic volume changes.

Idiopathic cervical dystonia (ICD) is by far the largest subgroup of dystonia. Still, its natural course is largely unknown. We studied the natural course of 100 ICD patients from our botulinum toxin clinics (age at ICD onset 45.8 ± 13.5 years, female/male ratio 2.0) over a period of 17.5 ± 11.5 years with follow-ups during botulinum toxin therapy and with semi-structured interviews. Two courses of ICD could be distinguished by symptom development of more or less than 6 months. ICD-type 2 was less frequent (19% vs 81%, p < 0.001), had a more rapid onset (8.7 ± 8.0 weeks vs 3.8 ± 3.5 years), a higher remission rate (92% vs 5%, p < 0.001) and a higher prevalence of excessive psychological stress preceding ICD (63% vs 1%, p < 0.001). In both ICD-types, the plateau phase was non-progressive. Significant differences in patient age at ICD onset, latency and extent of remission, female/male ratio and prevalence of family history of dystonia could not be detected. ICD is a non-progressive disorder. ICD-type 1 represents the standard course. ICD-type 2 features rapid onset, preceding excessive psychological stress and a high remission rate. These findings will improve prognosis, treatment strategies and understanding of underlying disease mechanisms. They contradict the widespread fear of patients of a constant and continued decline of their condition. Excessive psychological stress may be an epigenetic factor triggering the manifestation of genetically predetermined dystonia.

BACKGROUND: Cervical dystonia (CD) is characterized by involuntary contractions of the cervical muscles. Data on long-term effectiveness of deep brain stimulation (DBS) are rare. The aim of this study was to evaluate the longitudinal ten years treatment efficacy of DBS in the globus pallidus internus (GPI).
METHODS: A retrospective single-center data analysis was performed on patients with idiopathic CD, who were treated with GPI DBS for at least 10 years. TWSTR severity score and individual sub-items were compared between pre and post DBS surgery (n = 15) over time.
RESULTS: There was a significant and persistent positive effect regarding the severity of TWSTRS between the conditions immediately before and 1, 5, and 10 years after establishment of GPI DBS (mean difference: 6.6-7 ± 1.6). Patients with increasing CD complexity showed a poorer response to established treatment forms, such as injection of botulinum toxin and were thus DBS candidates. Especially a predominant torticollis was significantly improved by DBS.
CONCLUSIONS: GPI DBS is an effective procedure especially in severely affected patients with a positive 10-year outcome. It should be considered in more complex CD-forms or predominant torticollis.

BACKGROUND: Neuroimaging studies have identified both brain structural and functional abnormalities in patients with idiopathic cervical dystonia (iCD), but often yield diverse results. We aim to find the specific and common neurostructural/functional abnormalities in iCD by conducting separate and multimodal meta-analyses across structural and functional neuroimaging studies.
METHODS: A systematic literature search was conducted to identify relevant publications. Separate meta-analysis for whole-brain voxel-based morphometry (VBM) studies and for functional imaging studies, and a multimodal meta-analysis across VBM and functional studies in iCD were conducted using anisotropic effect size-based signed differential mapping.
RESULTS: We included twenty-seven studies, including nine structural datasets comprising 152 iCD patients and 188 healthy controls, and seventeen functional datasets describing 352 iCD patients and 296 healthy controls. The multimodal analysis showed overlap between anatomic and functional changes in bilateral precentral and postcentral gyri, bilateral paracentral lobules, right supplementary motor area, bilateral median cingulate/paracingulate gyri, right caudate nucleus and thalamus, right cerebellum and lingual gyrus. We also found gray matter alterations alone in bilateral dorsolateral superior frontal gyri, left middle temporal gyrus, right inferior parietal gyrus, and left cerebellum; and altered functional activity alone in right fusiform gyrus, bilateral precuneus.
CONCLUSIONS: The current meta-analyses revealed significant conjoint and dissociated brain structural and functional abnormalities in iCD, and emphasized the involvement of cortico-thalamo-basal ganglia circuit and cerebellum.

In recent years, cerebellar abnormalities have gained increasing attention as possible physiopathological substratum of idiopathic cervical dystonia (ICD), but a consistent pattern of cerebellar structural modifications has not yet been established. We systematically investigated the presence of volumetric alterations of cerebellar gray (GM) and white matter (WM) in ICD patients, as well as their clinical relevance.
In this two-centers prospective cross-sectional study, from May 2013 to December 2017, 27 patients with ICD and 27 age- and sex-comparable healthy controls underwent brain MRI including 3D T1-weighted sequences for volumetric analyses. Between-group differences in terms of gray matter and cerebellar peduncles volumes were investigated using both region of interest (ROI)-based and voxel-based approaches using the SUIT tool (SPM12), and significant volumetric changes were correlated with clinical impairment (as measured with the Tsui score) and presence of tremor.
ICD patients showed significant volumetric reduction of cerebellar GM in the anterior lobe and lobule VI, resulting from both ROI-based (p ≤ 0.009) and voxel-based (p ≤ 0.04) analyses, while small clusters of reduced WM volume were found in the right cerebellum and left midbrain (p = 0.04), along with reduced volume of the bilateral superior (p = 0.04) and middle (p = 0.03) cerebellar peduncles. Furthermore, higher middle cerebellar peduncles volume was associated with the presence of tremor (p = 0.04).
Our data show evidence of a specific pattern of cerebellar structural abnormalities in ICD patients, with volume loss mainly involving cortical GM regions related to the somatotopic representation of the affected body parts and, to a lesser extent, cerebellar peduncles.

OBJECTIVE: Hyperkinetic movement disorders represent a heterogeneous group of diseases, different from a genetic and clinical perspective. In the past, neurophysiological approaches provided different, sometimes contradictory findings, pointing to an impaired cortical inhibition as a common electrophysiological marker. Our aim was to evaluate changes in interhemispheric communication in patients with idiopathic cervical dystonia (ICD) and spinocerebellar ataxias (SCAs).
METHODS: Eleven patients with ICD, 7 with genetically confirmed SCA2 or SCA3, and 10 healthy volunteers were enrolled. The onset latency and duration of the ipsilateral silent period (iSPOL and iSPD, respectively), as well as the so-called transcallosal conduction time (TCT), were then recorded from the abductor pollicis brevis of the right side using an 8-shaped focal coil with wing diameters of 70 mm; all these parameters were evaluated and compared among groups. In SCAs, changes in neurophysiological measures were also correlated to the mutational load.
RESULTS: iSPD was significantly shorter in patients with SCA2 and SCA3, when compared both to control and ICD (P < .0001); iSPOL and TCT were prolonged in SCAs patients (P < .001). Changes in iSPD, iSPOL, and TCT in SCAs are significantly correlated with the mutational load (P = .01, P = .02, and P = .002, respectively).
CONCLUSIONS: This is the first study to assess changes in interhemispheric communication in patients with SCAs and ICD, using a transcranial magnetic stimulation protocol. Together with previous data in Huntington\'s disease, we suggest that these changes may underlie, at least in part, a common disease mechanism of polyglutamine disorders.