Training lip force by oral screens. Part 3: Outcome for patients with stroke and peripheral facial palsy.

The aim of this study was to investigate whether training with an oral screen can improve oral motor function in patients with stroke and peripheral palsy. The participants in the study were eight patients with orofacial dysfunction after stroke, included 7-14 months after onset, and seven patients with peripheral palsy, included 14-28 months after onset. A customized oral screen in acrylic was made for each participant. The screen had a tube around the handle to allow air to pass when measurements were made of the perioral muscle force. When measuring the ability to suck, the hole was sealed with wax. The participants trained with the oral screen two times daily for 5 min. Measurements were made at baseline, after 1 month and thereafter every third month until no further improvement was achieved. Measurements were made with two different instructions, to squeeze and to suck. In the stroke group, muscles around the mouth improved when pouting and smiling; these participants also achieved statistically significant changes when sucking. For the peripheral palsy group, little improvement could be seen when pouting and smiling. However, these patients reported less or no drooling, and the measurements for sucking increased significantly for six of the seven patients. The first recorded significant change was seen in the stroke group after 4 weeks training and in the group with peripheral palsy after 6 weeks. Training with a custom-made oral screen can significantly improve perioral muscle force and the ability to create negative intraoral pressure. The patients reported less leakage in saliva, drink, and food as well as fewer bite injuries and less food accumulation.

Measuring lip force by oral screens. Part 1: Importance of screen size and individual variability.

To reduce drooling and facilitate food transport in rehabilitation of patients with oral motor dysfunction, lip force can be trained using an oral screen. Longitudinal studies evaluating the effect of training require objective methods. The aim of this study was to evaluate a method for measuring lip strength, to investigate normal values and fluctuation of lip force in healthy adults on 1 occasion and over time, to study how the size of the screen affects the force, to evaluate the most appropriate measure of reliability, and to identify force performed in relation to gender. Three different sizes of oral screens were used to measure the lip force for 24 healthy adults on 3 different occasions, during a period of 6 months, using an apparatus based on strain gauge. The maximum lip force as evaluated with this method depends on the area of the screen size. By calculating the projected area of the screen, the lip force could be normalized to an oral screen pressure quantity expressed in kPa, which can be used for comparing measurements from screens with different sizes. Both the mean value and standard deviation were shown to vary between individuals. The study showed no differences regarding gender and only small variation with age. Normal variation over time (months) may be up to 3 times greater than the standard error of measurement at a certain occasion. The lip force increases in relation to the projected area of the screen. No general standard deviation can be assigned to the method and all measurements should be analyzed individually based on oral screen pressure to compensate for different screen sizes.

Measuring lip force by oral screens Part 2: The importance of screen design, instruction and suction.

The aim of this study was to find a reliable method for measuring lip force and to find the most important factors that influence the measurements in terms of magnitude and variability. The hypothesis tested was that suction is involved and thus the instruction and the design of the oral screen are of importance when measuring lip force. This is a methodological study in a healthy population. This study was conducted in a general community. The designs of the screens were soft and hard prefabricated screens and 2 semi-individually made with a tube allowing air to pass. The screens and the instructions squeeze or suck were tested on 29 healthy adults, one at a time and on 4 occasions. The test order of the screens was randomized. Data were collected during 4 consecutive days, and the procedure was repeated after 1 month. The participants were 29 healthy adult volunteers. The instruction was an important mean to distinguish between squeezing and sucking. The design of the screen affected the lip force so that it increases in relation to the projected area of the screen. A screen design with a tube allowing air to pass made it possible to avoid suction when squeezing. By measuring with and without allowing air to pass, it was possible to distinguish between suction related and not suction related lip force. The additional screen pressure when sucking was related to the ability to produce a negative intraoral pressure. In conclusion lip force increases in relation to the projected area of the screen, sucking generally increases the measured lip force and the additional screen pressure when sucking is related to the ability to produce a negative intraoral pressure.