# HAL Training in Spinal Cord Injured Patients: A Narrative Review of 10 Years Experience
## 3 Results
### Clinical Trials  
In 2013, [PERSON] et al. [8] published a paper summarizing findings of previous studies on robotic devices used in clinical settings with the conclusion that robot-assisted rehabilitation is controversial. They introduced the newly developed HAL and had the intention to investigate the feasibility of HAL rehabilitation training for patients with limited mobility. The study collective consisted of 12 stroke patients, four patients with musculoskeletal diseases, eight SCI patients, and 14 other diseases. The SCI patients were all in a chronic stage (1-6 years since SCI) and included four paraplegia as well as four tetraplegia. Four of them were incomplete, one complete, one had spina bifida, one central cervical cord injury, and one spinal dural arteriovenous fistula. Patients performed 16 HAL sessions in eight weeks using a walking device or treadmill for 90 min (net walking time 20 min). One of these patients dropped out in course of the study due to neuropathic pain and for one patient the baseline measurement was not assessed, as he was unable to amulate with any assistance. Therefore, only six SCI patients were included in the statistical analysis. In this study, the functional ambulation results were presented for the whole group of participants included in the statistical analysis (\(n=27\)). Since the informative value about this diverse patient collective, in the view of the authors of the review, is very limited, we refrain from presenting it here in detail. However, significant improvements in gait speed, number of steps, and cadence were observed, as assessed by the 10-Meter-walking-test (10 MWT). Improved Timed-Up-and-Go test (TUG) and Berg balance scale (BBS) results were also observed, but they were not statistically significant [8]. The only SCI specific result that was given is a large effect size in gait speed (Cohan d = 0.78), which leads the authors to conclude that training effectiveness in SCI patients can be expected. The conclusion of this study states that HAL training is feasible, safe and effective in patients with limited mobility [8]. Results that are more detailed are provided by a study from [PERSON] et al. [9] involving eight patients in chronic stage (1-19 years since SCI) after traumatic SCI. Included patients had incomplete paraplegia (AIS B/C/D, \(n=4\)) or complete paraplegia (AIS A, \(n=4\)) with zones of partial preservation (ZPP) and performed treadmill training using HAL five times per week for 90 days (mean number of sessions 51.75 \(\pm\) 5.6). Treadmill associated results improved over all patients for walking speed and walking time, but no information was provided on the statistical significance except for ambulated distance, which increased from 195.88 \(\pm\) 166.71 m to 954.13 \(\pm\) 380.35 m (\(p<0.05\)). Functional assessments were the 10 MWT, TUG, 6-Minute-Walk-Test (6 MWT), walking index for SCI II (WISC II) score, and lower extremity motor score (LEMS). The authors state that although the WISCI II score did not improve statistically, three patients showed functional improvements in gait abilities. For the 10 MWT a significant increase in gait speed similar to [PERSON] et al. [8] and decrease in number of steps were found as well as a decreased time for the TUG and increased LEMS. Similarly, they reported significant improvement for the 6 MWT, although it should be noted that only three participants were able to take part in the baseline measurement (with an average walking distance of 187 \(\pm\) 162.2 m) and the five others who did not participate (scored as 0 m) decimated the total baseline data to 70.1 \(\pm\) 130 m. However, the subgroup who performed the 6 MWT at baseline improved their walking distance to 287.3 \(\pm\) 229.4 [9]. In this study, information on statistical significance was not given in detail, it was only stated that the \(p\) value is <0.05. Thus, it remains unknown whether the improvements were highly significant or whether the results were just at the threshold of significance.