PP12.6 – 2933: Objective evaluation of functional outcomes using the assessment of motor and process skills (AMPS) following deep brain stimulation (DBS). Can we improve what really matters to children and young people?

Abstract

Objective To objectively evaluate activity of daily life (ADL) outcomes following deep brain stimulation (DBS) in childhood dystonia. Methods This prospective case series study involves 27 young people with dystonia/dyskinesia at least 1 year following DBS. The Assessment of Motor and Process Skills (AMPS) was used as primary outcome measure to evaluate ADL. Results are analysed based on aetiology (primary and secondary dystonias). The AMPS was administered by a trained occupational therapist (OT) in a consecutive sample of 27 young people pre and post-DBS. All assessments were videoed and 55% of the videos were blind rated by an independent OT expert in AMPS scoring. Inter-rater reliability was established between the two OT raters. Secondary dystonias had a majority of children and young people with diagnosis of cerebral palsy (CP). Manual Ability Classification system levels (MACS) I-IV and Gross Motor Function Classification System (GMFCS) levels I-IV were included. Motor and process scores for primary and secondary dystonia groups are presented in both, logits and standard scores. The AMPS follows Rasch methodology taking into account the task level of difficulty, rater severity and child's age. A change of >0.30 logits in considered significant. Logits below 2 for motor and 1 for process skills are considered below the cut-off point. Results All groups showed significant improvement in motor and process skills following DBS. All young people (including primary dystonias) showed motor skills below 2 logits and the majority also below the cut-off of 1 for process skills pre-DBS. Two young people with primary dystonias didn't show a significant improvement in motor skills though their process skills improved and two others deteriorated in process skills despite improvement in motor skills. Process skills improved for the majority of children. Conclusion DBS improved functional performance using a blind rated objective assessment of ADL, independently of the dystonic phenotype.