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Our Projects

Use of Rice Congee for Thickened Liquids for Dysphagic Patients

Seeing the popularity of rice congee consumption among Asian families, the present study examined the possibility of preparing thickened liquids from rice congee of different thickness levels that are commonly prescribed for individuals with swallowing disorders. This project aims to make use of the two most common rice varieties in Hong Kong, indica and japonica rice grains, and to prepare rice congee from which thickened liquids were extracted. By varying the water-to-rice ratio, cooking time, optional reheating on a frying pan, and temperature, slightly thick, mildly thick, moderately thick, and extremely thick liquids were obtained.

Recipes for extracting thickened liquids of different consistencies from rice congee cooked with indica and japonica rice grains were established. The consistency levels specified by the International Dysphagia Diet Standardization Initiative (IDDSI) framework were followed. Results revealed that the consistency of the product varied with water-to-rice ratio, cooking time and temperature. Our findings support that thickened liquids obtained from rice congee prepared accordingly can be used as an alternative to thickened liquids preparing using commercial thickeners.

Ng, M. L., & Lui, H. Y. (2022). Rice congee as an alternative to thickened liquids for patients with swallowing disorders. Journal of Texture Studies, 53(3), 405-416.
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Effect of Temperature on Thickness

Studies have revealed that consistency of liquid food changes with temperature. Yet, the exact relationship between temperature and consistency of food bolus is still not known. The present study examined the change in liquid consistency with temperature. Water thickened at the four thickness levels (slightly thick, mildly thick, moderately thick, and extremely thick) using starch-based and xanthan-gum-based thickeners was studied. Consistency was measured using a Bostwick consistometer at different temperature points between 5°C and 85°C. Regression analyses were subsequently carried out.

Consistometric flow distance (in cm) associated with mildly thick, moderately thick, and extremely thick liquids thickened using starch-based thickener measured at different temperature points between 5˚C and 85˚C.
Consistometric flow distance (in cm) associated with mildly thick, moderately thick, and extremely thick liquids thickened using xanthan-gum-based thickener measured at different temperature points between 5˚C and 85˚C.
Our findings indicated definite but different relationships between temperature and consistency of thickened liquids prepared using starch- and gum-based thickeners. While there was a general trend of decreasing consistency in liquids prepared using gum-based thickener with temperature, a quadratic relationship between temperature and consistency was found for starch-based thickener. The consistency was generally the highest at very low and very high temperature, but the lowest at 65°C. These findings confirmed a definite effect of temperature on bolus consistency. When preparing thickened liquids for patients with dysphagia, caregivers and clinicians should take into consideration the effect of temperature, as it has a definite effect on liquid consistency.

Ng, M., Mak, C., Mak, J., & Xiong, M. (2022). Effect of temperature on thickness of starch- and gum-based thickened liquids for dysphagic individuals. Food Hydrocolloids for Health, 2, 1-7.

Lombard Effect in Alaryngeal Speech

For late-stage laryngeal cancer patients, when other invention options fail, total laryngectomy is often used as the last resort to remove the pathological larynx (voice box). Due to the loss of their phonatory apparatus during the procedure, they need to learn to use an alternative speaking method (known as alaryngeal phonation) in order to regain verbal communication. To update, four alaryngeal speaking methods are available: esophageal speech, tracheoesophageal speech, electrolaryngeal speech, and pneumatic artificial laryngeal speech.

Research revealed that, regardless of type, alaryngeal speech are associated with reduced intelligibility and, particularly for esophageal and electrolaryngeal speech, diminished loudness. Patients’ ability to speak more loudly becomes an important aspect of speech rehabilitation.

Imagine talking with someone in a noisy cocktail party. It is very natural that you will automatically raise your voice in order to be heard by your friend(s). This process is known as the Lombard effect. This is unconscious and done unnoticed, and how much you raise your voice seems to depend on the level of the background noise. That is, the louder the background is, the more loudly you will speak.

The present study attempts to make use of the Lombard effect to help alaryngeal speakers speak more loudly. We measured their vocal output when they are exposed to loud background noise at 60, 65, 70, 75, 80, 85, 90, 95, and 100 dB SPL (white noise). Preliminary findings indicate that they are able to raise their vocal output by varying amounts.
It is expected that, in the future, this strategy can be used to enhance their vocal output and used as a biofeedback to improve their intelligibility.
Ng, M. (2021). The use of the Lombard effect in improving alaryngeal speech. Journal of Voice, 35(1), 18-28.
Ng, M., & Tsang, G. (2019). The Lombard effect associated with Chinese male alaryngeal speech. International Journal of Speech-Language Pathology, 21(6), 584-592.

Cantonese English accent reduction and native-like accent enhancement characterization and training for primary school students and English teachers.

Accent refers to errors or articulatory deviations observed when producing sounds of the foreign language (L2). In general, the greater is the deviation in articulation of L2 sounds, the more is the observed accent. Hong Kong is an international city, and for a native Cantonese speaker, being able to speak English as a second language has many obvious advantages. Yet, it has been observed that many local Hong Kongers are speaking English with a varying degrees of accent. Our previous research studies have indicated that such errors in producing L2 English sounds largely originate from Cantonese – the speakers’ mother tongue.

This project aims at characterizing the phonological gap between the best achievable accent of HKCE by primary school students as represented by that of the best students and local English teachers, and that of native British RP English accent, by means of perceptual evaluation and acoustical analysis, both under a native British English and a Cantonese framework. By measuring some speech physics parameters, we will gather quantitative evidence to experiment with our pilot training for students and teachers on how to reduce their Cantonese English accent and enhance it to one which is more native-like. We will construct a web platform to disseminate the analysis results and quantitative measurement of monitoring of the effects and progress of training.