Objetivos relacionados a la comprensión de los Conceptos y Teorías Científicas

A few studies have looked at PwS with a mild to moderate paresis in the acute stages, with others focusing on those more severely affected. An early study by Powell et al (1999) involving 60 participants (30 in an intervention group and 30 in a control group) (Powell, Pandyan, Granat, Cameron, & Stott, 1999). The treatment group were given stimulation to the wrist extensors 3 times a day for 30 minutes for 8 weeks. However, the ES was not used to support functional movement or task practice. Participants were followed up at the end of the 8-week intervention period and 24 weeks after the end of intervention. Significantly greater increases in isometric wrist extensor strength were seen at the end of intervention in the treatment group compared to the control, and these changes were maintained at follow up. A trend (p=0.11) towards better functional improvement in the treatment group compared with the control group was also seen in the total ARAT scores. The trend continued at the follow up measure of total ARAT scores, but differences between the groups were also not statistically significant.

A single-blinded study investigated the effects of functional electrical therapy (FET), consisting of an exercise program of voluntary arm movements opening, closing, holding and releasing of objects assisted by a neural prosthesis (electrical stimulation) (M. B. Popovic, Popovic, Sinkjaer, Stefanovic, & Schwirtlich, 2003). The FET group received 30 minutes a day for 3 weeks in addition to conventional therapy. The

control intervention was the same program of exercises, for the same duration daily without the electrical stimulation. The participants were divided into higher functioning groups (HFG) and lower functioning groups (LFG) for each intervention dependant on their ability to actively extend the wrist and fingers (M. B. Popovic et al., 2003). There were four groups in all, and with only 28 participants overall there was not more than 8 participants in any one group. However, the FET and control groups showed a recovery trend in all outcome measures, and gains were maintained at a 26 week follow up. The gains in FET groups were much larger compared with the gains in control groups. The LFG subjects showed less improvement than the HFG in both the FET and control groups. One explanation for this finding could be that LFG’s found more difficulty performing the required functional tasks, even with the aid of stimulation, as the stimulation only assisted finger and thenar muscles and not more proximal muscles. For the LFG the average number of successful repetitions per session was 0 at the start for both the FET and control groups. Small increases in number of repetitions were seen in both groups. Despite larger increases in the number of repetitions in the HFG’s, the average number of repetitions achieved were still low at the end of the intervention period (29.9 for the FET and 15.4 for the controls) in terms of promoting plasticity. A statistically significant decrease in muscle spasticity measures by the Ashworth scale was only seen in subjects in the HFG who had FET. This study also looked at the users’ satisfaction with the Reduced Upper Extremity Motor Activity Log and both HFG’s showed increased satisfaction at the end of the study, and there was a statistically significant difference between the groups in favour of the FET group. Satisfaction was lower in both the LFG’s.

A later pilot study by Alon et al (2007) of 15 individuals, used a well-designed training program, comparing FES with tailored task specific therapy with task specific therapy alone, all participants regained hand function, with significantly better improvements in the FES group for all outcome measures (Alon, Levitt, & McCarthy, 2007). Following an informative but mainly descriptive review of FES applications, Popovic et al (2009) also suggested that repetitive, active movement mediated by electrical stimulation can enhance motor re-learning following damage to the CNS,

2009). Despite this being in line with theories related to learned non-use Popovic did not back up the conclusions with any detailed analysis of the studies described.

Any type of task practice can be very difficult to achieve in severely affected or completely paralysed PwS, without the use of a technology, such as FES (M. R. Popovic, Thrasher, Zivanovic, Takaki, & Hajek, 2005). There have been various studies looking at the use of FES in this stroke population. Popovic investigated 13 subjects with no active movement at baseline. After 12 to 16 weeks of training with FES and conventional therapy, compared with a control group who received conventional therapy, all subjects in the FES group had active movement and were able to use their upper limb in activities of daily living (ADLs). The majority of the control participants did not improve their arm and hand functions significantly and were not able to use them in ADLs (M. R. Popovic et al., 2005).

Alon et al (2008) compared FES plus task specific training to task-specific training alone in 26 severely affected acute stroke subjects (Alon, Levitt, & McCarthy, 2008). The study found, despite the small numbers and high dropout rate, the FES plus training group showed improved outcomes compared to the task specific training group alone. The H200 neuroprosthesis was used, which stimulates the wrist and finger extensors only in timed delivery of stimulation, and in severely impaired PwS no consideration was given to the function and stability of the elbow, shoulder or shoulder girdle, an issue raised by Mann et al (2005) previously (Mann, Burridge, Malone, & Strike, 2005). Compliance data was also lacking, making dose effect conclusions difficult. Interestingly, after 12 weeks training a plateau was not seen in functional improvements, however longer term follow-up measures were not carried out.

FES was found to be not superior to conventional therapy in a study of 23 acute participants with severe or complete paralysis (Mangold, Schuster, Keller, Zimmermann-Schlatter, & Ettlin, 2009). Group imbalances and small numbers weakened the validity of the intergroup comparisons. This study also explored the users' perspective and this highlighted an issue found in lower limb FES, as in a 45- minute therapy session 15-20 minutes were spent donning and doffing the FES, highlighting the need for user-friendly systems. Thrasher et al (2008) found

statistically significant improvements when FES was combined with conventional therapy, compared to conventional therapy alone (Thrasher, Zivanovic, McIlroy, & Popovic, 2008). In a small blinded study of 21 subjects’ improvements were seen in object manipulation, palmar grip torque, pinch grip and an array of other outcome measures.

Despite small sample sizes and methodological difficulties, the results suggest FES, when combined with conventional therapy and/or task specific training may be effective in reducing motor impairment and increasing function. A few studies have included a follow up period to further assess the intervention and this is discussed in section 2.8.8. Only Popovic et al (2003) who looked also at satisfaction, took any account of the users’ perspective on the intervention (M. B. Popovic et al., 2003). Authors agree FES can assist those with a more severe impairment often referred to quoting Barkers 2005 paper as “not enough to work with” (Barker & Brauer, 2005). FES can act as “bridge” for this group who otherwise would not be able to participate in repetitive task practice (Hayward, Barker, & Brauer, 2010; Howlett, Lannin, Ada, & McKinstry, 2015; Page, Harnish, Lamy, Eliassen, & Szaflarski, 2010).