Examining the evidence on neuromuscular electrical stimulation for swallowing: a meta-analysis.
OBJECTIVE
To evaluate the effect of transcutaneous neuromuscular electrical stimulation (NMES) on swallowing rehabilitation.


METHODS
MEDLINE, PubMed, CINAHL, NML, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, doc online, Google, and EMBASE were searched for studies using NMES to treat dysphagia between January 1966 and August 2006.


METHODS
Included were published or unpublished, English-language, clinical trials with a quantifiable dependent variable.


METHODS
Two researchers independently performed data extraction. A random-effects model was used to pool study results. The Cochran Q test was used to evaluate heterogeneity, and a funnel plot and Egger test were used to evaluate publication bias. A best-research synthesis using a methodological quality analysis was conducted.


RESULTS
A total of 81 studies were reviewed. Seven were accepted for analysis. A significant summary effect size was identified for the application of NMES for swallowing (Hedges g, 0.66; P<.001). Heterogeneity was significant for the combined trials (P<.10). When 2 outlier trials were removed, heterogeneity was no longer significant (P<.08). Publication bias was not identified on the funnel plot or Egger test (P = .25). Best-evidence synthesis showed indicative findings in favor of NMES for swallowing.


CONCLUSIONS
This preliminary meta-analysis revealed a small but significant summary effect size for transcutaneous NMES for swallowing. Because of the small number of studies and low methodological grading for these studies, caution should be taken in interpreting this finding. These results support the need for more rigorous research in this area.
Carnaby-Mann
Giselle D
GD
Department of Behavioral Science and Community Health, 101 S Newell Dr, Room 4160, PO Box 100175 Health Science Center, University of Florida, Gainesville, FL 32610, USA. GMann@phhp.ufl.edu
Crary
Michael A
MA
D015982:Bias; D003679:Deglutition / Q000502:physiology*; D003680:Deglutition Disorders / Q000534:rehabilitation / Q000628:therapy*; D004599:Electric Stimulation Therapy / Q000706:statistics & numerical data; D006801:Humans; D009469:Neuromuscular Junction / Q000502:physiology*; D012107:Research Design; D016896:Treatment Outcome