Voice Resonance Week 3: Acoustic Analysis of Voice

What is the pitch correlate?

Frequency

Mean Fundamental Frequency

Average number of vibrations per second

Frequency Range

Minimum and maximum 

Standard Deviation of Frequency

Variation seen from mean frequency; the accepted range from the mean

A clinician notices a patient’s fundamental frequency varies significantly from moment to moment. What specific frequency-related measure might they analyze, and what would a high value suggest?

They would analyze the Standard Deviation of Frequency; a high value suggests instability or inconsistency in pitch, which may indicate a voice disorder.

If a speaker's voice shows both a very low and very high frequency during speech, what measure does this relate to, and why is it important?

It relates to the Frequency Range. It’s important because it shows vocal flexibility and expressiveness; a narrow range may indicate vocal monotony or pathology.

What is the loudness correlate? 

Intensity 

What are the intensity-related measures?

Mean amplitude, intensity range, and standard deviation of amplitude

What would a higher intensity look like?

Higher peaks

You observe that a patient’s voice shows very little variation in loudness. What measure might be useful to evaluate this and what might it indicate?

Standard Deviation of Amplitude; low variation may suggest monotone speech or possible vocal fatigue or neurological issues.

A voice sample has unusually high peaks in its waveform. What does this indicate about the intensity and how might it be perceived?

It indicates high intensity (amplitude), which may be perceived as shouting or vocal strain.

What are the quality correlates? 

Noise, perturbation, and cepstral 

What is noise (in terms of quality)?

Extra signal in the voice sample

Noise to Harmonic Ratio (NHR)

Bad energy (noise) divided by good noise (harmonic); only for phonation 

If a patient's NHR is significantly elevated, what does this say about their voice quality?

It suggests that there is a lot of noise (bad energy) compared to harmonic content, indicating poor voice quality and possibly a vocal pathology.

Jitter (perturbation measure)

Cycle to cycle variation in frequency 

Shimmer (perturbation measure)

Cycle to cycle variation in intensity

When are perturbation measures used?

Only for phonation

What does higher jitter shimmer mean? Lower?

Higher jitter/shimmer indicates irregular frequency and amplitude cycles, suggesting unstable vocal fold vibration and poor voice quality, which relates to the mucosal wave; lower suggests stable, regular vocal fold vibration.

When can you use the cepstral measures? 

For both speech and phonation samples 

Waveforms

Illustrates amplitude over time

Spectrum

Illustrates amplitude and frequency over time

Cepstrum

The inverse of a spectrum 

Cepstral Peak Prominence (CPP)

Index of voice quality; gives a numerical score called Cepstral Spectral Index of Dysphonia (CSID)

When can CSID and CPP be used? 

For both running speech samples and sustained vowel phonations 

A patient receives a low CPP score. What does this indicate about their voice quality?

A low CPP indicates poor harmonic structure and breathy/hoarse voice quality, which can signal dysphonia.

Sensitivity

How well a test identifies someone with a disorder as having a disorder 

Specificity

How well a test identifies a person with normal voice as having a normal voice