Subjective and Objective Evaluation of Speech in Adult Patients with Unrepaired Cleft Palate

To explore the speech outcomes of adult patients through subjective perception evaluation and objective acoustic analysis, and to compare the differences in pronunciation characteristics between speakers with adult patients with unrepaired cleft palate and their non-cleft peers.

Subjective evaluation indicators included speech intelligibility, nasality, and consonant missing rate, whereas objective acoustic parameters included normalized vowel formants, voice onset time, and the analysis of three-dimensional spectrogram and spectrum, were carried out on speech samples produced by 2 groups of speakers: (a) speakers with unrepaired cleft palate ( n = 65, mean age = 25.1 years) and (b) typical speakers ( n = 30, mean age = 23.7 years).

Compared with typical speakers, individuals with unrepaired cleft palate exhibited a lower speech intelligibility with higher nasality and consonant missing rate, the missing rate is highest for the 6 consonants syllables The acoustic parameters are mainly manifested as differences in vowel formants and voice onset time.

The results revealed important acoustical differences between adult patients with unrepaired cleft palate and typical speakers. The trend of spectral deviation may have contributed to the difficulty in producing pressure vowels and aspirated consonants in individuals with speech disorders related to cleft palate.