title: Reliable lip force measurement in healthy controls and in patients with stroke: a methodologic study.
abstract: A prefabricated oral screen has shown promising results as a muscle self-training device to improve the lip function of stroke patients affected by oropharyngeal dysphagia. However, a technique for the measurement of lip muscle force, whether in healthy individuals or in stroke patients, is lacking. The present study was designed to (1) test the intra- and interreliability of lip force measurements by means of a newly devised Lip Force Meter, LF100, (2) determine a normal lower limit for lip force in newtons (N), and (3) ascertain the instrument's sensitivity and specificity. LF100 is a modified strain gauge for recording the ability of lips to withstand pressure from a predentally placed oral screen. Forty-two healthy controls and 22 stroke patients agreed to participate in the trial. The controls and patients were examined three times with the LF100, with 2-min rest intervals, twice by investigator MH and once by investigator MO. Intrainvestigator reliability with the LF100 proved excellent in both controls and patients: ICC was 0.83 and 0.90, respectively. Interinvestigator reliability was good or excellent in both groups: ICC was 0.71 and 0.91. There was a significant difference in lip force between controls and stroke patients (mean = 24.7 +/- 6.3 N and 9.5 +/- 5.5 N, p < 0.001). The sensitivity of LF100 was 91% and the specificity 95%. The cutoff level for normal lip force was 15 N. The LF100 showed itself to be a suitable and reliable instrument for measuring lip force.
authors.affiliation: Department of Otorhinolaryngology, Hudiksvall Hospital, Hudiksvall, Sweden. mary.hagg@lg.se
authors.forename: Mary
authors.initials: M
authors.lastname: Hägg
authors.forename: Margaretha
authors.initials: M
authors.lastname: Olgarsson
authors.forename: Matti
authors.initials: M
authors.lastname: Anniko
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003679:Deglutition; D003680:Deglutition Disorders / Q000503:physiopathology*; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008046:Lip / Q000294:innervation / Q000502:physiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020521:Stroke / Q000503:physiopathology*