Dependencies of Acoustic Signal and Image Recordings of Phonatory Movement of the Pharyngoesophageal Mucosa in Laryngectomy Patients Using High-speed Video Endoscopy and a Biomechanical Model
Conditions: Larynx Cancer, Laryngectomy; Status
Sponsor: Osijek University Hospital

 
 
 
 
 
Study protocol and statistical analysis plan 
 
 
Phonatory Movement of the Pharyngoesophageal Mucosa in 
Laryngectomy Patients 
NCT05561920 
 
 
 
 
 
 
August 1, 2022. 
 
 
 
 
 
 

Background  
 
The treatment of advanced laryngeal cancer involves the removal of the entire larynx. 
After removal of the larynx, the pharyngoesophageal segment (PES) is created by 
reconstructing the soft tissue of the pharynx and oesophagus, and its vibration creates a 
substitute voice. High-speed video endoscopy (HSV) is the only method that visualises and 
measures the vibration of the PES after a laryngectomy. The acoustic characteristics of three 
forms of rehabilitated voice of laryngectomised individuals (oesophageal voice, 
tracheoesophageal voice using a voice prosthesis and electrolarynx) have been satisfactorily 
described, but the interdependence of acoustic and visual representations of the phonatory 
movement of the PES is still insufficiently studied. In recent years, biomechanical models have 
been developed to analyse the vibration of the PES, but consistent results have not yet been 
obtained that would explain whether the parameters from the analysis of the waveform of 
the PES can be compared with the parameters obtained from the acoustic analysis of the 
voice of a laryngectomised patient. 
 
Effective rehabilitation focuses on optimising speech and swallowing, which leads to a 
good integration of the laryngectomised person into society. One step towards achieving this 
goal is a thorough assessment of their voice and communication experiences, as well as 
analysing the phonatory movements of the PES using HSV technology. Therefore, the primary 
aim of this study was to investigate the relationship between the morphological 
characteristics of the PES and the acoustic parameters of the tracheoesophageal voice (TE) 
with voice prosthesis, as determined by acoustic analysis and biomechanical model. In 
addition, the aim was to investigate the impact of loss of voice in terms of psychological and 
socioeconomic problems in laryngectomy patients using Croatian version of the Self-
Evaluation of Communication Experiences after Laryngectomy (SECEL:HR) questionnaire. 
 
Design of a research  
 
The study is designed as a prospective observational study and includes patients who 
have undergone a total laryngectomy, who have completed oncological treatment and 
undergone voice rehabilitation, who have had regular follow-up visits to the ENT clinic and 
who meet the study criteria. A consent form will be signed. 
 
Materials and Methods  
 
A total of 55 participants were included in this study. They had all undergone a total 
laryngectomy, TE voice with a voice prosthesis rehabilitation and oncological treatment at 
least six months prior to participation. Exclusion criteria included individuals with acute upper 
or lower respiratory tract infections, a second primary cancer in the upper aerodigestive tract 
or lungs, and individuals with neurological or psychiatric disorders.  
Each participant underwent a complete otolaryngological examination. The video 
recordings of the PES were made with a 90° rigid HSV system Wolf 5562 HRES ENDOCAM 
(frame rate: 4000 fps, resolution: 256×256 pixels). All subjects phonated the vowel “a” at a 
comfortable pitch and volume. Visual assessment of the HSV recordings was performed 
including the assessments of the overall quality of the recordings and  the assessments of 
anatomical and morphological features of the PES: amount of saliva, visibility and shape of 

the PES, location of visible vibration, presence of a mucosal wave and regularity of the 
vibration.  
Each respondent completed the Croatian version of the Self-Evaluation of 
Communication Experiences after Laryngectomy (SECEL:HR) questionnaire, specifically 
designed to address the communication needs of patients who have undergone a 
laryngectomy. The first part of SECEL:HR examines patient-relevant data, while the second 
part consists of 35 items designed as questions or statements to explore communication 
experiences. Patients rate the frequency of these communication difficulties on a Likert scale 
(0-never, 1-sometimes, 2-often, 3-always). The 35 items are divided into 3 subscales: General 
(0-15 points), Environment (0-42 points) and Attitude (0-45 points). Item number 35 is a 
separate question: "Do you talk the same amount now as you did before your laryngectomy?" 
and is scored with the rating categories "yes"," "more" and "less". The total numerical score 
ranges from 0 to 102, with a higher score indicating greater difficulty and poorer postoperative 
adaptation of speech communication. 
The acoustic analysis of the TE voice with a voice prosthesis was performed in a quiet 
room (ambient noise < 50 dB) with a microphone placed 30 cm from the mouth to create 
optimal conditions for recording and analysis. Three consecutive measurements were taken. 
The voice recordings were analysed using the acoustic programme lingWAVES (Voice and 
speech analyser version 2.x software). The following parameters were recorded from the 
central part of the best recording: fundamental frequency (F0) (Hz), jitter (%), shimmer (%) 
and the intensity of substitute voice (dB). The value of the maximal phonation time (MPT; ms)  
was taken as the value of the longest possible relaxed phonation of the vowel “a”. 
A multi-mass coupled biomechanical model was developed as a multidimensional 
time sequence of PES mucosal contractions in the form of the opening width observed for 
each frame of the video time sequence at different angles. 
The biomechanical model of the PES analyses non-stationary pharyngoesophageal 
vibrations and draws conclusions about the temporal characteristics of tissue stiffness, 
oscillatory mass, pressure and geometric distributions within the PES. The biomechanical 
model identifies mathematical dependencies and analyses extracted time signals of the PES 
opening and contours (i.e. the opening and closing of the vibrating mucosa of the PES). 
Using the PES waveform, we were able to calculate cycle duration, open and closed phase 
duration (s), fundamental frequency (Hz), mean shimmer (dB), relative shimmer (%), mean 
jitter (s) and relative jitter (%). 
 
Statistical analysis  
Categorical variables were presented as absolute and relative frequencies. Fisher's 
exact test was employed to analyse differences in proportions and to compare categorical 
data between groups. The normality of the distribution of continuous variables was 
assessed using the Shapiro-Wilk test. Descriptive statistics for numerical data were reported 
using the median and interquartile range. Comparisons across three or more groups were 
conducted using the Kruskal-Walli’s test. All reported p-values were two-tailed, with 
statistical significance set at an alpha level of 0.05. Statistical analyses were performed using 
MedCalc® Statistical Software version 23.1.1 (MedCalc Software Ltd, Ostend, Belgium; 
https://www.medcalc.org; 2025) and IBM SPSS Statistics version 23.0 (IBM Corp., Armonk, 
NY, USA, released in 2015).