Functional Electrical Stimulation Therapy: Enabling Function Through Reaching and Grasping



Fig. 41.1
Typical locations of surface stimulation electrodes used to retrain reaching and grasping functions in clients with severe stroke using the Compex Motion (Compex SA, Switzerland)




 


b.

Percutaneous electrodes consist of thin wires that are inserted through the skin into the underlying muscle tissue where they remain in place for a maximum of 30 days (Chae and Hart 2003).

 

c.

Implanted electrodes are permanently implanted into the muscle or around a peripheral nerve. BION™ microstimulators (Advanced Bionics Corporation, USA) are implanted via a hypodermic needle (Loeb 2002); are cylindrical in shape (2-mm diameter and 16-mm length), and are powered and controlled via radio waves from an external controller carried by the client. Implanted electrodes, with the exception of the BION™ microstimulators, require lengthy surgical procedures to implant.

 



Until recently, implanted and percutaneous electrodes were considered to have the ability to deliver higher stimulation selectivity with less electrical charge applied, as compared to surface stimulation electrodes. The MyndMove stimulator and electrode system is purported to deliver highly specific muscle contractions using only a fraction of the charge that implanted systems require to produce equivalent muscle contractions.

The OT’s recommendation for use of FES versus FEST should be based on clients’ goals, tolerance for invasive procedures, prognosis, and resources.



FEST Intervention


FEST is typically applied using surface electrodes three to five times per week for 8–16 weeks, with each session ranging from 45 to 60 min in duration.

FEST consists of preprogrammed electrical stimulation and manual support of joint motion by the OT, which together enables the client to achieve functional motion.


Outcome Measures


OTs implementing evidence-based practice perform standardized assessments to characterize the client’s impairment and disability, identify subgroups suitable for specialized care, and determine treatment effectiveness. The reader is encouraged to routinely use the assessments described herein for clients with stroke and tetraplegia.

The choice of the assessment tool is dictated by the intent of the assessment. The Chedoke McMaster Stroke Assessment (CMSA; Gowland et al. 1993) is an example of a valid measure with sound psychometric properties used to describe UE function and determine the prognosis after stroke. Less than 10 % of stroke clients with Chedoke McMaster Stages of Motor Recovery (CMSMR) stages 1 or 2 recover their ability to reach and grasp (Rand et al. 1999).

There is currently a paucity of psychometrically robust UE functional assessments for individuals with tetraplegia. Many UE function assessments are not sufficiently sensitive enough to detect changes in UE function and hand function. The routinely used Functional Independence Measure (FIM; Dodds et al. 1993) and Spinal Cord Independence Measure (SCIM; Catz et al. 1997) are insufficient to characterize UE functional recovery following tetraplegia.

We propose two standardized assessments for assessing UE function and hand function pre- and post-FEST intervention:



1.

GRASSP—The Graded Redefined Assessment of Strength, Sensibility, and Prehension is a standardized UE function impairment measure for individuals with complete or incomplete tetraplegia. The GRASSP has good inter-rater reliability (0.84–0.96), test retest reliability (0.86–0.98), construct validity (sensation and strength testing is more sensitive than ISNCSCI sensory and motor testing), and concurrent validity with SCIM, SCIM self-care subscores, and the Capabilities of Upper Extremity Questionnaire (0.57–0.83; Kalsi-Ryan et al. 2012).

 

2.

TRI-HFT—The Toronto Rehabilitation Institute Hand Function Test evaluates gross motor function of unilateral grasp and focuses on lateral pinch, pulp to pulp pinch, palmar grasp, and strength of both power and lateral grasps (Popovic et al. 2005). The TRI-HFT has good inter-rater reliability (0.98), concurrent validity with the FIM self-care subscores (0.56–0.73) and is highly sensitive in detecting changes in voluntary UE function pre- and postintervention (Kapadia et al. 2012; Popovic and Thrasher 2004).

 

Either one of these outcome assessments should be paired with an impairment-specific functional abilities evaluation (i.e., SCIM for individuals with tetraplegia and the CMSMR for individuals with stroke). The recent paradigm shift from using FES as an orthotic system to using it as a therapy to augment UE strength and motor function has resulted in improved voluntary reaching and grasping . There is substantial level I evidence of the therapeutic efficacy of FEST.



Results



Evidence-Based Practice



A) Surface FEST for Stroke Clients









































Authors

journal year

design

sample size

Subjects

intervention

outcomes

Results/conclusions

Popovic et al. (2002)

Pre–Post

N = 16

Subjects: 16 stroke subjects allocated to a higher functioning group (HFG; 4 FEST, 4 controls) and a lower functioning group (LFG) (4 FEST, 4 controls) based on the ability to extend their affected wrist, metacarpophalangeal (MCP) and interphalangeal (IP) joints

Intervention: 3-week FEST applied 30 min/day. Controls received conventional therapy

Outcomes: UEFT

Improvements for both HFG and LFG post-FEST. As the HFG had greater benefits, it was recommended that HFG was best suited for FEST

Results of these three studies suggest that both acute and chronic stroke subjects benefited from FEST

Popovic et al. (2003) RCT

N = 28

Subjects: 28 acute stroke subjects allocated to HFG (8 FEST, 8 controls) and LFG (6 FEST, 6 controls)

Intervention: 3-week FEST applied 30 min/day. Controls received conventional therapy

Outcomes: UEFT, DT, MAS, RUE/MAL

Popovic et al. (2004b)

Pre–Post

N = 16

Subjects: 16 chronic (> 1 year)

post-stroke subjects (8 HFG, 8 LFG)

Intervention: 3-week FEST, 30 min/day

Outcomes: UEFT, DT, MAS

Gritsenko and Prochazka (2004)

Pre–Post

N = 6

Subjects: 6 subjects, >

 12 months post-stroke, reasonable shoulder and elbow active ROM, but unable to grasp/release objects

Intervention: FEST with instrumented workstation applied for 12 consecutive workdays, 1 h/day

Outcomes: FMA, WMFT and kinematics

Kinematics and WMFT showed improvement during treatment and on discharge, but were lower at follow-up

Popovic et al. (2005) RCT

N = 13

Subjects: 13 acute stroke subjects (5 FEST, 8 controls), CMSMR score = 1 or 2

Intervention: 12–16-week FEST, 3–5 sessions/week, 45 min/session. Controls received conventional therapy

Outcomes: FIM, BI, CMSMR, FMA, and TRI-HFT

Statistically significant results achieved on all tests, except FIM in favor of FESTFIM was not sufficiently responsive to capture improvements in arm/hand function

Thrasher et al. (2008)

RCT, N = 21

Pre–Post, N = 7

Subjects:

RCT of 21 acute stroke subjects (10 FEST, 11 controls), CMSMR stages 1 or 2, and a 2–7-week duration between stroke and the start of intervention

Pilot study using FEST with 7 chronic stroke subjects, CMSMR score = 2 or 3

Intervention:

RCT: 12–16-week intervention, 5 days/week, 45 min/session

Pilot Study: 12–16-week FEST, 3 days/week, 45 min/session

Outcomes: TRI-HFT, FIM, BI, FMA, and CMSMR arm and hand scores

RCT: Both FEST and control groups improved in all outcome measures. FEST group had significant improvements compared to the control group on the BI, FMA, and CMSMR (p < .05) with no significant differences in the FIM

Mangold et al. (2009)

RCT

N = 23

Subjects: 23 subjects (12 FEST, 11 controls), acute or subacute stroke, severe hemiparesis to complete hemiplegia of the arm and/or hand (maximum CMSMR = 3)

Intervention: 4-week training program, 3–5 sessions/week for UE function training, 45 min/session. In the intervention group, 3 sessions were FEST

Outcomes: EBI subscore, CMSMR arm and hand

Significant improvements in all outcome measures in the FEST group


BI Barthel Index, EBI Extended BI, DT Drawing Test, FMA Fugl–Meyer Assessment, MAS Modified Ashworth Scale, RUE/MAL Reduced Upper Extremity Motor Activity Log, UEFT Upper Extremity Function Test, WMFT Wolf Motor Function Test


FEST Protocol Example for Clients with Stroke


Based on the literature evaluating the efficacy of FEST in individuals with severe chronic stroke (Popovic et al. 2005; Thrasher et al. 2008), the following stimulation protocol, therapy dose, and frequency have demonstrated good clinical outcomes:



1.

One-hour FEST 3–5 times/week for 16–20 weeks

 

2.

Balanced, biphasic, current regulated electrical pulses

 

3.

Pulse amplitude from 10 to 50 mA

 

4.

Pulse width from 100 to 250 µs

 

5.

Pulse frequency of 40 Hz

 

Since neuromuscular recovery in stroke clients occurs from proximal to distal, FEST should be separated into two phases: (1) focus on proximal functions, such as reaching forward to grab an object, or touching one’s face (i.e., shoulder and elbow flexion/extension, forearm supination/pronation), followed by (2) focus on distal functions, such as grasping and manipulating objects (i.e., wrist flexion/extension and finger movements). An example of an individual with stroke learning to voluntarily open his hand (Fig. 41.2). The case study provides more details of a specific FEST protocol.



A143976_2_En_41_Fig2_HTML.jpg


Fig. 41.2
FEST of a client with stroke learning to voluntarily open his hand


C) Surface FEST for Clients with Tetraplegia


There is level 1a evidence (Popovic et al. 2006, 2011) and level 2 evidence (Kapadia et al. 2011) of the efficacy of FEST for improving hand function, maintaining functional gains at long-term follow-up, increased independence, and quality of life (Kapadia et al. 2011; Popovic et al. 2006, 2011) among clients with subacute tetraplegia (Table 41.1). Subacute tetraplegic subjects who received OT with FEST showed significantly greater functional abilities on the FIM self-care, SCIM upper extremity, and TRI-HFT scores for manipulation of objects when compared to the conventional OT control group. Four subjects available at 6-month follow-up continued to either improve or maintain their gains in voluntary hand function , as assessed using FIM self-care subscores and SCIM self-care subscores (Kapadia et al. 2011; Fig. 41.3).



A143976_2_En_41_Fig3_HTML.jpg


Fig. 41.3
FEST applied to a client with tetraplegia using lateral grip when stacking wooden blocks




Table 41.1
Table summarizing level 1 and 2 evidence of FEST trials for individuals with tetraplegia


















Authors

Journal year

Design

Sample size

Subjects

Intervention

Outcomes

Results/conclusions

Popovic et al. (2006)

RCT

N = 21

Subjects: 10 subjects with complete SCI (6 FEST, 4 controls) and 11 subjects (6 FEST, 5 controls) with incomplete SCI

Intervention: surface FEST

Outcome: FIM, SCIM and TRI-HFT

Although this study was not powered to determine treatment efficacy, these results suggested that short-term use of FEST for grasping had the potential to improve grasping in clients with motor complete or incomplete SCI

Kapadia et al. (2011)

RCT

N = 22

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May 21, 2017 | Posted by in GENERAL | Comments Off on Functional Electrical Stimulation Therapy: Enabling Function Through Reaching and Grasping
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