An F-18-FDG PET study of cervical muscle in parkinsonian anterocollis

• Authors: Gonzalo J. Revuelta, Medical University of South Carolina; Jaime Montilla, University of South Florida; Michael Benatar, University of Miami; Alan Freeman, Emory University; Thomas Wichmann, Emory University; Hyder Jinnah, Emory University; Mahlon DeLong, Emory University; Stewart Factor, Emory University
• Journal Title: Journal of the Neurological Sciences
• Volume: Volume 340, Number 1-2
• Publisher: Elsevier | 2014-05-15, Pages 174-177
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.jns.2014.03.023
• Subjects: Biology, Neuroscience; Health Sciences, Medicine and Surgery
• Keywords: Science & Technology; Life Sciences & Biomedicine; Clinical Neurology; Neurosciences; Neurosciences & Neurology; Anterocollis; FDG-PET; Parkinson's disease; EMG; Dystonia; MULTIPLE SYSTEM ATROPHY; DROPPED HEAD SYNDROME; CLINICAL SUBTYPES; FOCAL MYOPATHY; DISEASE; CAMPTOCORMIA; DYSTONIA; DEFORMITIES; NECK

Abstract

The underlying etiology of parkinsonian anterocollis has been the subject of recent debate. The purpose of this study is to test the hypothesis that anterocollis in parkinsonian syndromes is associated with dystonia of the deep cervical flexors (longus colli and capitis). Eight patients with anterocollis, six in the setting of parkinsonism and two primary cervical dystonia control subjects with anterocollis underwent prospective structured clinical evaluations (interview, examination and rating scales), systematic electromyography of the cervical extensor musculature and 18F-FDG PET/CT studies of cervical muscles to examine evidence of hypermetabolism or overactivity of deep cervical flexors. Subjects with parkinsonian anterocollis were found to have hypermetabolism of the extensor and sub-occipital muscles but not in the cervical flexors (superficial or deep). EMG abnormalities were observed in all evaluated patients, but only one patient was definitely myopathic. Meanwhile, both dystonia controls exhibited hypermetabolism of cervical flexors (including the longus colli). In conclusion, we were able to demonstrate hypermetabolism of superficial and deep cervical flexors with muscle 18F-FDG PET/CT in dystonic anterocollis patients, but not in parkinsonian anterocollis patients. The hypermetabolic changes seen in parkinsonian anterocollis patients in posterior muscles may be compensatory. Alternative explanations for anterocollis include myopathy of the cervical extensors, or unbalanced rigidity of the cervical flexors, but this remains to be proven.