Validation of an Intelligibility Test Based on Acoustic-Phonetic Decoding of Pseudo-Words: Overall Results from Patients with Cancer of the Oral Cavity and the Oropharynx.

OBJECTIVES: Loss of intelligibility is a major complaint for patients with speech disorders, as it affects their everyday communication and thus contributes to a decrease in their quality of life. Several tests are available to measure intelligibility, but these tests do not take into account the evaluators' ability to restore distorted sequences. Due to this ability, the evaluator will tend to recognize words despite phonetic distortions, and speech production deficit can go undetected. The results of these tests therefore overestimate the intelligibility of patients and may mask real functional limitations. We propose a new test which uses a large number of pseudowords in order to neutralize the unwanted perceptual effects that cause this overestimation. The purpose of this test is to measure the speech production deficit. It is not intended to assess the communication deficit. Our objective is to validate this test based on acoustic-phonetic decoding of productions from patients with speech disorders. MATERIALS AND METHODS: We tested this method with a population of 39 healthy participants and 78 post-treatment patients with cancers of the oral cavity and the oropharynx (HNC patients). Each speaker produced 52 pseudowords taken from randomly generated lists from large common dictionary, each list of 52 pseudowords containing the same number of phonemes. Forty everyday listeners then transcribed these productions. The orthographic transcriptions were phonetized and compared to the expected phonetic forms. An algorithm provided a Perceived Phonological Deviation score (PPD) based on the number of features that differed between the expected forms and the transcribed items. The PPD thus provided a score representing the loss of intelligibility. RESULTS: The 39 participants in the control group demonstrated significantly lower PPD scores compared to the 41 patients with a T1T2 tumor size or compared to the 37 patients with a T3T4 tumor size. The differences between the three groups were significant. If we use the PPD as a predictor to identify patients versus control group subjects, the AUC of the ROC curve is equal to 0.94, which corresponds to an outstanding group separability. A PPD threshold at 0.6 features per phoneme is the boundary between normal and dysfunctional speech. The analysis showed a close correlation between the PPD and a clinical judgment of the disorder severity obtained from experts. CONCLUSION: This test appears to be effective in measuring the intelligibility of speakers at a phonological level, in particular in the case of head and neck cancers.

Construction of an automatic score for the evaluation of speech disorders among patients treated for a cancer of the oral cavity or the oropharynx: The Carcinologic Speech Severity Index.

BACKGROUND: Speech disorders impact quality of life for patients treated with oral cavity and oropharynx cancers. However, there is a lack of uniform and applicable methods for measuring the impact on speech production after treatment in this tumor location. OBJECTIVE: The objective of this work is to (1) model an automatic severity index of speech applicable in clinical practice, that is equivalent or superior to a severity score obtained by human listeners, via several acoustics parameters extracted (a) directly from speech signal and (b) resulting from speech processing and (2) derive an automatic speech intelligibility classification (i.e., mild, moderate, severe) to predict speech disability and handicap by combining the listener comprehension score with self-reported quality of life related to speech. METHODS: Eighty-seven patients treated for cancer of the oral cavity or the oropharynx and 35 controls performed different tasks of speech production and completed questionnaires on speech-related quality of life. The audio recordings were then evaluated by human perception and automatic speech processing. Then, a score was developed through a classic logistic regression model allowing description of the severity of patients' speech disorders. RESULTS: Among the group of parameters subject to extraction from automatic processing of the speech signal, six were retained, producing a correlation at 0.87 with the perceptual reference score, 0.77 with the comprehension score, and 0.5 with speech-related quality of life. The parameters that contributed the most are based on automatic speech recognition systems. These are mainly the automatic average normalized likelihood score on a text reading task and the score of cumulative rankings on pseudowords. The reduced automatic YC2SI is modeled in this way: YC2SIp  = 11.48726 + (1.52926 × Xaveraged normalized likelihood reading ) + (-1.94e-06 × Xscore of cumulative ranks pseudowords ). CONCLUSION: Automatic processing of speech makes it possible to arrive at valid, reliable, and reproducible parameters able to serve as references in the framework of follow-up of patients treated for cancer of the oral cavity or the oropharynx.

Design and Development of a Speech Intelligibility Test Based on Pseudowords in French: Why and How?

Purpose The current intelligibility tests performed on speakers with atypical speech production are limited by the ability of listeners to restore distorted sequences. This results in a measure that is overvalued when compared with the real articulatory performance. In this article, we present a new intelligibility test in order to neutralize the commonly encountered bias in traditional perception-based assessments. We present the construction of the acoustic-phonetic decoding task and its first test during a perceptual judgment test of intelligibility and during a result comparison with a global perceptual evaluation. Method We developed a very large pseudoword directory including about 90,000 forms that respect French phonotactic constraints. From this directory, we have created lists of pseudowords intended to be recorded for the constitution of the corpus. These lists are established due to an algorithm integrating predefined linguistic constraints and produced by 47 speakers (nine healthy and 38 patients). We then performed a perceptual judgment of intelligibility test with 20 listeners who transcribed these productions. Results At the end of the data processing stage, we obtained a Perceived Phonological Deviation (PPD) score for each speaker that reflects the average number of features altered per phoneme. We then compared the PPD score with a global intelligibility score derived from a global perceptual assessment of intelligibility and of the alteration severity. Conclusions The current findings confirm that a speech intelligibility test based on pseudowords in French achieves fine-grained PPD scores, which enables discrimination between patients and healthy speakers. Moreover, the PPD score is related to the global intelligibility score, especially in severity. Further studies are needed to better understand the discrimination power of this intelligibility test based on an acoustic-phonetic decoding task.

On the relationship between handedness and hand-digit mapping in finger counting.

The purpose of the current investigation was to evaluate hand-digit mapping in finger counting in French children and adults and whether handedness might constraint hand-digit mapping. To this aim, hand-digit mapping used when counting from one to ten by means of fingers, together with performance-based and preference-based measures of handedness, were evaluated in French individuals of four different age groups (4-5 years old, 6-7 years old, 10-11 years old and 24-47 years old). Irrespective of the age group, analyses revealed a strong tendency to use first the right hand to count from one to five and then the left hand to count from six to ten. In addition, a significant interaction between hand-digit mapping and hand preference was found, with participants who used first their right hand to count reporting higher right-hand preference in unimanual activities. These findings are discussed in light of recent studies assuming a link between finger-counting habits and numerical processing.