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Sustained Phonation is an activity under the Voice category of the Active Tasks. Active tasks are part of Apple’s ResearchKit framework and help involve the users directly with research through their iPhones.

The Qolty Mobile Assessments utilizes the Apple ResearchKit™ framework  to define a large number of predefined tasks in six broad categories: motor activities, fitness, cognition, voice, audio, and hand dexterity. We utilize these functions for your use in your study, making it easy to capture objectively reported data from your patients.

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Introduction

The process of producing sounds through quasi-periodic vibration is known as phonation. Voice and speech disorders can arise due to lesions, congenital and neurological disorders. Phonation time can be a significant determinant of organic or functional dysphonia. Maximum phonation time is often employed as a measure of vocal function due to its simplicity and ease of use. The assessment usually requires the subject to sustain the phonation of a vowel sound for the longest period possible. Patients with vocal disorders due to inflammation of vocal cords, developmental disorders or trauma, usually tend to have difficulty in maintaining sustained phonation in comparison to healthy individuals.

Methods

The assessment should be preferably performed in a sound-proof booth, although it can also be performed in a quiet room. The participants are asked to sustain voicing of a vowel, usually /a/, at a comfortable pitch and loudness levels for at least 5 seconds after a deep breath. The same process is usually repeated three times. The task can be extended to assess sustained phonation at different pitches and loudness. The data is noted for the maximum phonation time and can also include values for pitch and loudness.

Methods

The assessment should be preferably performed in a sound-proof booth, although it can also be performed in a quiet room. The participants are asked to sustain voicing of a vowel, usually /a/, at a comfortable pitch and loudness levels for at least 5 seconds after a deep breath. The same process is usually repeated three times. The task can be extended to assess sustained phonation at different pitches and loudness. The data is noted for the maximum phonation time and can also include values for pitch and loudness.

Active task: Voice

Sustained Phonation is an activity under the Voice category of the Active Tasks. Active tasks are part of Apple’s ResearchKit framework and help involve the users directly with research through their iPhones.

The Voice activity involves voice recording which can be later evaluated for different purposes of research such as looking at the power spectrum and the ease with which sound can be produced.

Sustained Phonation task instructions

  1. Hold the device microphone close to your mouth.
  2. Initiate the task.
  3. Wait for the countdown to begin the task.
  4. Take a deep breath and say “Aaaaah” keeping a steady vocal volume so that the audio bar remains blue.
  5. Task completed.

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Applications

Parkinson’s Disease

Speech disorders can be observed as early as five years before the diagnosis of Parkinson’s diseases, thus making it a viable marker for early diagnosis of the disease (Vaiciukynas et al., 2017). The study investigated sustained phonation and text-dependent speech modalities signals for screening Parkinson’s disease. Parkinson’s patients were asked to sustain phonation of the vowel /a/ at a comfortable pitch and loudness lasting at least 5 seconds. The task was repeated three times for phonation modality.

 

Down Syndrome

Jeffery et al., 2017 investigated the relationship between perceived voice qualities and acoustic measures in patients with Down Syndrome. The patients were asked to imitate phonations, within their vocal range, of the vowels /i/, /u/, and /a/ at predetermined target pitches. The medial portion of the vowels was analyzed for fundamental frequency, harmonics-to-noise ratio, jitter, and shimmer using Praat. Spectrograms were used in the identification of the presence and the duration of subharmonics at onset and offset, and mid-vowel, while auditory evaluation assessed the presence of diplophonia. Perturbation data was highest and lowest for vowels /a/ and /u/ respectively. Intermittent subharmonic productions were apparent in spectrograms, of which some overlapped with perceived diplophonia.

 

Myasthenia Gravis

Konstantopoulos et al., 2017 used quantitative methods to study phonatory and speech function in Myasthenia Gravis patients. Phonatory function assessment was done using sustained phonation of the vowel /a/ in combination with reading, the results of which were age-matched with healthy controls. Data from sustained phonation yielded values for the average fundamental frequency, the standard deviation of the fundamental frequency, and the jitter (period-by-period variability as a measure of vocal stability). All of which had higher values in comparison to healthy controls.

 

Vocal Tremor

Hemmerich’s et al., 2017 study intended to find the correlation between the overall vocal tremor severity with the distribution and the tremor severity in the structures involved. The results were compared with two healthy age-matched individuals. Sustained phonation task revealed a strong positive correlation between Tremor index and the severity of vocal tremors.

 

Cleft Palate

Children with cleft lip and palate commonly experience speech problems related to change in resonance. In their study with 30 children with the congenital cleft of the palate (8 to 15 years), Dodderi et al., 2016 evaluated the voice low to high tone ratio (VLHR) values for phonation samples. Patients underwent three trials of sustained phonation of vowels /a/, /i/ and /u/, recorded at their comfortable pitch and loudness. The trials were repeated post-operation. The results of the study revealed a significant decrease in VLHR values post-operation, and it was concluded that VLHR parameter was a viable index of nasality measure.

 

Attention Deficit Hyperactivity Disorder

Barona-Lleo et al., 2016 in their prospective study aimed to establish specific vocal aerodynamic patterns in ADHD patients as a phenotypic feature of the disease. Children (5 to 13years) diagnosed with ADHD were evaluated for repeated sustained vowels, syllables, words, and sentences over several trials. The functional voice analysis revealed that the subglottal pressure is high and the transglottal airflow is low in ADHD children compared with the age and gender-matched control group.

Results and Data Analysis

The sustained phonation task allows data collection of the maximum sustained phonation, the pitch and the volume of the phonation all of which can be used for different purposes of functional voice assessment. The task also assesses the ease with which the voice can be produced and observation of certain mechanics of voice production.

The following graph depicts sample data for adjusted means of maximum phonation time as observed in healthy older adults based on their gender and age (Maslan et al., 2010).

Strengths and Limitations

Strength

The Sustained Phonation task is a frequently used clinical tool for assessing phonatory mechanics. The task is simple and easy to administer.

Limitations

Despite being a simple task, it must be used in combination with other tools and assessment to gather a more thorough insight of the vocal mechanics and dysfunctions.

Summary

  • Sustained Phonation is a simple and easy to implement test of glottic efficiency.
  • Phonation time can be a significant determinant of organic or functional dysphonia.
  • Sustain Phonation requires only a timer and audio recorder.
  • The participants are asked to sustain voicing of a vowel, usually /a/, at a comfortable pitch and loudness levels.
  • Apple ResearchKit’s Audio Active task allows administration of the test via the user’s iPhone device.
  • Sustained Phonation may be difficult to administer in patients that are unable to cooperate with the process.
  • Sustained Phonation cannot be used as standalone to identify all aspects of voice dysfunction.

References

Barona-Lleo L, Fernandez S (2016). Hyperfunctional Voice Disorder in Children With Attention Deficit Hyperactivity Disorder (ADHD). A Phenotypic Characteristic? J Voice. 2016 Jan;30(1):114-9. doi: 10.1016/j.jvoice.2015.03.002

Dodderi T, Narra M, Varghese SM, Deepak DT (2016). Spectral Analysis of Hypernasality in Cleft Palate Children: A Pre-Post Surgery Comparison. J Clin Diagn Res. 10(1):MC01-3. doi: 10.7860/JCDR/2016/15389.7055.

Jeffery T, Cunningham S, Whiteside SP (2017). Analyses of Sustained Vowels in Down Syndrome (DS): A Case Study Using Spectrograms and Perturbation Data to Investigate Voice Quality in Four Adults With DS. J Voice. pii: S0892-1997(17)30151-0. doi: 10.1016/j.jvoice.2017.08.004.

Maslan J, Leng X, Rees C, Blalock D, Butler SG (2010). Maximum phonation time in healthy older adults. J Voice. 25(6):709-13. doi: 10.1016/j.jvoice.2010.10.002.

Konstantopoulos K, Christou YP, Vogazianos P, Zamba-Papanicolaou E, Kleopa KA (2017). A quantitative method for the assessment of dysarthrophonia in myasthenia gravis. J Neurol Sci. 377:42-46. doi: 10.1016/j.jns.2017.03.045.

Vaiciukynas E, Verikas A, Gelzinis A, Bacauskiene M (2017). Detecting Parkinson’s disease from sustained phonation and speech signals. PLoS One. 12(10):e0185613. doi: 10.1371/journal.pone.0185613.

Ritter, S. (2014). Apples Research Kit Development Framework for iPhone Apps Enables Innovative Approaches to Medical Research Data Collection. Journal of Clinical Trials, 05(02). doi:10.4172/2167-0870.1000e120

Hemmerich AL, Finnegan EM, Hoffman HT (2017). The Distribution and Severity of Tremor in Speech Structures of Persons with Vocal Tremor. J Voice. 31(3):366-377. doi: 10.1016/j.jvoice.2016.05.004.