Impacts of Prism Adaptation Treatment on Spatial Neglect and Rehabilitation Outcome: Dosage Matters

We examined whether number of prism adaptation treatment (PAT) sessions in regular clinical practice would predict spatial neglect (SN) improvement and rehabilitation outcomes. We reviewed clinical records from 16 U.S. rehabilitation hospitals where neurological patients were assessed for SN using the Catherine Bergego Scale (CBS) and if SN was detected, and may have received PAT. Multiple linear regression was used to predict CBS Change (indicating SN improvement) in 520 patients who received PAT while considering age, sex, diagnosis, time post diagnosis, CBS at baseline, neglected side of space, and length of stay. Another set of regression models including the same variables and adding Function Independent Measure (FIM (R)) at admission was used to predict FIM Gains (indicating rehabilitation outcomes) in 1720 patients receiving PAT or not. We found that greater number of PAT sessions predicted greater CBS Change, especially in patients with moderate-to-severe neglect. Number of PAT sessions also positively correlated with Total FIM, Motor FIM, and Cognitive FIM Gains regardless of SN severity classification at baseline. Furthermore, number of PAT sessions predicted CBS Change and FIM Gains among patients completing <= 8 PAT sessions but not among patients with >= 8 sessions, who however, showed greater CBS Change with increased PAT frequency (i.e., fewer days between two consecutive sessions). Receiving more once-daily PAT sessions predicted greater improvement in SN and rehabilitation outcomes. Receiving PAT at a higher frequency for 8 or more sessions predicted better SN improvement. Thus, dosage matters. The study provides practice-based evidence that PAT is appropriate for inpatient rehabilitation.