Naofumi Tanaka

Identification of a simple screening tool for dysphagia in patients with stroke using factor analysis of multiple dysphagia variables

OBJECTIVEnTo identify a most useful and simple clinical screening tool to predict videofluoroscopic aspiration in patients with stroke.nnnDESIGNnFactor analysis of multiple dysphagia variables and sensitivity and specificity testing with chi-square test.nnnPATIENTSnSixty-one consecutive stroke patients with symptoms suggestive of dysphagia admitted to a university hospital and its 4 affiliated hospitals in Japan.nnnMETHODSnFactors were extracted from 6 oromotor examinations (lip closure, tongue movement, palatal elevation, gag reflex, voice quality and motor speech function), 2 swallow screen tests (saliva swallowing test and our modified water swallowing test using 30 ml of water) and 4 parameters evaluated with a videofluoroscopic swallow study. Sensitivity and specificity of each dysphagia-related variable was determined against aspiration in a videofluoroscopic swallow study.nnnRESULTSnFactor analysis revealed that cough/voice change in the water swallowing test and aspiration on videofluoroscopic swallow study belonged to the same factor. Chi-square analysis showed that cough/voice change in the water swallowing test was the only variable that was significantly associated with aspiration on videofluoroscopic swallow study, with a sensitivity of 72% (95% CI: 61-83%) and a specificity of 67% (CI: 55-79%) as a predictor of aspiration (p<0.05).nnnCONCLUSIONnWe recommend our modified 30 ml water-swallowing test as a useful single task-screening tool to detect aspiration.

Development of a short version of the motor FIM for use in long-term care settings.

OBJECTIVEnTo develop a short version of the motor Functional Independence Measure (FIM) for use in long-term care settings.nnnPARTICIPANTSnFor model construction, the participants were 398 community-dwelling persons with disability (mean age 79.3 years (SD 10.3)) who were receiving visiting nurse services. For cross-validation, 169 patients with stroke (mean age 78.0 years (SD 11.2)) in the chronic phase and 187 patients with stroke (mean age 63.4 years (SD 12.7)) in the recovery phase.nnnDESIGNnModel construction and cross-validation study.nnnMAIN OUTCOME MEASURESnThe second power of correlation coefficient (R2) was used for agreement analysis between the short and the full version. Cross-validation of the models was estimated with the intraclass correlation coefficient (ICC).nnnRESULTSnFive to 7 motor FIM items were selected for the models based on Rasch calibration and consideration of internal consistency. Total motor FIM was estimated with the 6-item and 7-item models with regression analysis, which yielded high correlations with the original 13-item motor FIM score (R2>0.95). Regression formulas derived from the models could estimate total motor FIM scores accurately in the 2 cross-validation samples (ICC > 0.98).nnnCONCLUSIONnThe short version of the motor FIM developed is a useful measure of functional status, not only in long-term care but in the recovery phase rehabilitation settings.

The size index as a motor unit identifier in electromyography examined by numerical calculation

A computer simulation was performed to investigate the size index as a motor unit identifier in electromyography. The size index calculated from the amplitude and area of the simulated motor unit action potential (MUP) was plotted against the distance between the needle electrode and current source to show how the index changes as a function of the distance. The index of the MUP also was plotted against the number of muscle fibers belonging to a single motor unit, the size of the motor unit territory, and the diameter of the muscle fibers in order to establish the major determinants of the index. The index was relatively constant for the distance less than 2 mm between the needle electrode and closest edge of the current source. It changed logarithmically with the number of muscle fibers and with the diameter of the fibers.