Paraplegic adaptation to assisted-walking : Energy expenditure during wheelchair versus orthosis use

Study Design: To study the energy cost of locomotion during ambulation with different orthoses (HIP Guidance Orthosis Orlau Parawalker (PW), n = 4; Reciprocating Gait Orthosis (RGO), n = 6; RGO + FNS, n = 4). Objectives: Since high energy costs of locomotion have been proposed as a major reason for early rejection of orthotic use, our aims were (a) to evaluate the impact of functional neuromuscular stimulation (FNS) on energy expenditure during orthosis-assisted ambulation; (b) to study whether energy expenditure data can predict the poor long-term patients' compliance and (c) to assess selection criteria for the assignment of the different types of orthosis. Setting: The study was completed at the Center of Sports Medicine and Center of Bioengineering, 'don C. Gnocchi' Foundation, IRCCS, Milan, Italy. Methods: The HR/V̇O2 relationship and the energy cost of locomotion (C) were studied in 14 patients (lesion level C7-T11) during wheelchair (WHCH) use at various speeds and during locomotion with different orthotic devices. Patients' short- and long-term compliance were assessed by questionnaires evaluating duration of and problems related to orthotic use. Results: (a) In patients using RGO + FNS the slope difference of HR/V̇O2 curves (Δ(s1)HR/ V̇O2) between WHCH and orthosis was significantly lower than in other groups (-3 beats 1-1 in RGO + FNS vs 43 and 52 beats 1-1 in RGO and PW, respectively); (b) neither C, nor VO2 peak, or Δ(s1)HR/V̇O2 correlated with orthosis duration of use; (c) in the RGO + FNS group, C was lower at maximal walking speed, which linearly correlated with maximal WHCH speed. Conclusion: (a) Electrical stimulation seems to improve locomotion, as a consequence of hemodynamic effects, but does not decrease energy expenditure, which remains high; (b) the poor long-term compliance to orthosis use cannot be predicted by the energy expenditure parameters; (c) the subjects who can reach high speeds by WHCH seem to be the most appropriate for RGO + FNS locomotion.