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

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).

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.

The study was completed at the Center of Sports Medicine and Center of Bioengineering, don C. Gnocchi Foundation, IRCCS, Milan, Italy.

The HR/VO2 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.

(a) In patients using RGO + FNS the slope difference of HR/VO2 curves (deltaslHR/VO2) between WHCH and orthosis was significantly lower than in other groups (-3 beats l(-1) in RGO + FNS vs 43 and 52 beats l(-1) in RGO and PW, respectively); (b) neither C, nor VO2 peak, or deltaslHR/VO2 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.

(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.