Background Convergence spasm refers to transient ocular convergence, miosis and accommodation associated with disconjugate gaze mimicking abducens palsy. While it may be a manifestation of brainstem pathology, this sign is often associated with conversion (somatisation) disorders and, if unrecognised as a sign of a psychogenic disorder, it may lead to unnecessary and occasionally invasive evaluation.
Methods To better characterise this neuro-ophthalmologic sign, 36 subjects were studied, 13 with psychogenic movement disorders, 11 with organic movement disorders and 12 normal controls. Patients were recorded during a manoeuvre to elicit convergence spasm and the videotapes were rated by two blinded raters on a scale of 0=normal, 1=mild convergence spasm and 2=marked convergence spasm.
Results Convergence spasm was present in 9/13 (69%) psychogenic movement disorders cases, 4/11 (36%) non-psychogenic movement disorders cases and 4/12 (33%) controls (p=0.049 when psychogenic vs non-psychogenic disorders or controls were compared). Inter-rater reliability analysis of the presence (rating 1 or 2) versus absence (rating 0) showed good agreement (27/36 or 75%; kappa 0.491, SE 0.141, p=0.002). Analysis for the presence of marked convergence spasm (rating 2) yielded agreement in 32/36 (88.9%) examinations (kappa 0.652, SE 0.154, p<0.001) with a specificity of 87% (sensitivity 15%).
Conclusion Convergence spasm may provide benefit in the clinical examination of psychogenic movement disorders patients.
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Competing interests RF and ADH received honoraria from Medlink Inc. JJ has received research grants from the following: Allergan Inc, Allon Therapeutics, Ceregene Inc, Chelsea Therapeutics, Diana Helis Henry Medical Research Foundation, EMD Serono, Huntington's Disease Society of America, Huntington Study Group, Impax Pharmaceuticals, Ipsen Ltd, Lundbeck Inc, Michael J Fox Foundation for Parkinson's Research, Medtronic, Merz Pharmaceuticals, National Institutes of Health, National Parkinson's Foundation, Neurogen, St Jude Medical, Teva Pharmaceutical Industries Ltd, University of Rochester and Parkinson's Study Group. JJ has been a consultant or advisory committee member for Allergan Inc, EMD Serono, Lundbeck Inc, Merz Pharmaceuticals, Michael J Fox Foundation for Parkinson's Research and Teva Pharmaceutical Industries Ltd. He serves on editorial advisory boards of Elsevier, Medlink: Neurology, Neurology in Clinical Practice, Neurotoxin Institute, Scientiae and UpToDate.
Patient consent Obtained.
Ethics approval This project was approved by the Baylor College of Medicine Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.