title: Factors predicting improvement in primary generalized dystonia treated by pallidal deep brain stimulation.
abstract: Despite the beneficial effects of Globus Pallidus internus (GPi) deep brain stimulation (DBS) in patients with primary generalized dystonia (PGD), the degree of improvement varies from one patient to another. The objective of this study was to examine the effects of clinical, anatomical (volume of the GPi), and electrical variables on the postoperative Burke-Fahn-Marsden Dystonia rating scale (BFMDRS) motor score to identify which factors may be predictive of the degree of improvement. We reviewed retrospectively the clinical records of 40 steady-state patients with PGD who had been treated by bilateral GPi lead implantation. The follow-up period was 2 to 8 years. The correlation between the electrical parameters (voltage, impedance, and current) and the clinical outcome was studied. An analysis of covariance was performed to identify factors predictive of the magnitude of improvement. The most influential factors according to the model are as follows: the preoperative BFMDRS score (P < 0.0001); age at surgery (P < 0.0001); the right GPi volume (P = 0.002); the left stimulated GPi volume (P = 0.005). No significant correlation was found between the electrical parameters used and the mean motor scores in steady state.
authors.affiliation: CHRU Montpellier, Service de Neurochirurgie, Montpellier, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Vasques
authors.forename: Laura
authors.initials: L
authors.lastname: Cif
authors.forename: Victoria
authors.initials: V
authors.lastname: Gonzalez
authors.forename: Claire
authors.initials: C
authors.lastname: Nicholson
authors.forename: Philippe
authors.initials: P
authors.lastname: Coubes
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D046690:Deep Brain Stimulation / Q000379:methods*; D020821:Dystonic Disorders / Q000628:therapy*; D005260:Female; D005917:Globus Pallidus / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D013223:Statistics as Topic; D055815:Young Adult