Effect of visual biofeedback of posterior tongue movement on articulation rehabilitation in dysarthria patients.

Articulation is driven by various combinations of movements of the lip, tongue, soft palate, pharynx and larynx, where the tongue plays an especially important role. In patients with cerebrovascular disorder, lingual motor function is often affected, causing dysarthria. We aimed to evaluate the effect of visual biofeedback of posterior tongue movement on articulation rehabilitation in dysarthria patients with cerebrovascular disorder. Fifteen dysarthria patients (10 men and 5 women; mean age, 70.7 ± 10.3 years) agreed to participate in this study. A device for measuring the movement of the posterior part of the tongue was used for the visual biofeedback. Subjects were instructed to produce repetitive articulation of [ka] as fast and steadily as possible between a lungful with/without visual biofeedback. For both the unaffected and affected sides, the range of ascending and descending movement of the posterior tongue with visual biofeedback was significantly larger than that without visual biofeedback. The coefficient of variation for these movements with visual biofeedback was significantly smaller than that without visual biofeedback. With visual biofeedback, the range of ascent exhibited a significant and strong correlation with that of descent for both the unaffected and affected sides. The results of this study revealed that the use of visual biofeedback leads to prompt and preferable change in the movement of the posterior part of the tongue. From the standpoint of pursuing necessary rehabilitation for patients with attention and memory disorders, visualization of tongue movement would be of marked clinical benefit.

Differences in biomechanical features of tongue pressure production between articulation and swallow.

Summary The purpose of this study was to compare the tongue pressure against the hard palate during the articulation of a monosyllable with that during swallowing. The participants were 20 healthy adults without swallowing or articulation disorder (10 men and 10 women, mean age ± standard deviation: 22·5 ± 0·9 years). Tongue pressure during articulation of [ki] (articulatory pressure) and during dry swallowing (swallowing pressure) was recorded by a 0·1-mm-thick sensor sheet with five measuring points attached to the hard palate. Biomechanical parameters such as maximal magnitude, duration, integrated value and slope gradient were compared between articulatory pressure and swallowing pressure at each measuring point. Although swallowing pressure was produced at each measuring point, articulatory pressure was found only in the posterior circumferential parts of the hard palate and was smaller in magnitude (14·9-16·7% of swallowing pressure) and integrated value, which meant the amount of work by tongue pressing (7·0-7·9%), shorter in duration (26·6-31·8%) and shallower in slope gradient, which meant the speed of tongue pressing (26·9-27·4%). Maximal magnitude was closely correlated with duration (R(2) = 0·386) and slope gradient (R(2) = 0·843) for articulatory pressure. These results first show the biomechanical differences between articulation and swallowing in terms of tongue contact with the hard palate. The findings suggest that tongue pressure measurement might be a useful investigation for patients with tongue motor disorder.

The effect of nasal speaking valve on the speech under experimental velopharyngeal incompetence condition.

Velopharyngeal incompetence (VPI) is a contributing factor to speech disorders, frequently accompanying disorders, such as cleft palate, congenital paralysis of the soft palate, and cerebrovascular disease. For the treatment of these types of dysarthria, a Nasal Speaking Valve (NSV), which regulates nasal emission utilizing one-way valve, has been reported to be effective. As the unpleasantness while wearing the NSV was less than that with the conventional Palatal Lift Prosthesis, the NSV could be worn for a longer period of time. As NSV is inserted into the nostrils, this device could easily be provided for edentulous patients. This study aimed to evaluate the effect of NSV on experimentally induced VPI condition. Intelligibility of monosyllabic speech, intelligibility of conversational speech, nasalance score and acoustic analysis were used to evaluate the effect of NSV. Local infiltration anaesthesia was achieved to the area of levator veli palatini muscle and tensor veli palatine muscle of seven adult male subjects. In all subjects, remarkable suppression of the soft palate movement could be observed after the local infiltration anesthesia. Although the utterance supported by NSV under the experimentally induced VPI condition was less natural than the normal utterance, the intelligibility was markedly improved by the device. From the results of this study, the acoustic properties of NSV on the pure VPI condition, which was enabled by the newly established experimental induction, were revealed. This experimental model was also proved to provide a basis for the improvement in the treatment modalities for VPI.

Nasal speaking valve: a device for managing velopharyngeal incompetence.

Velopharyngeal incompetence is a contributing factor for speech disorders, and other frequently accompanying disorders, such as cleft palate, congenital paralysis of the soft palate and cerebrovascular disease. A palatal lift prosthesis (PLP) has been fabricated for managing velopharyngeal incompetence to improve speech. Because of discomfort, such as difficulty in swallowing or vomiting reflex, while wearing the PLP, rigorous adjustment is required. Patients may have difficulty becoming accustomed to using the prosthesis. This article reports on a newly developed device, the nasal speaking valve, for improving hypernasal speech caused by velopharyngeal incompetence.