Speech Acoustics 1

Clinical Application of Frequency and Intensity

Variables

• Frequency Variables• Amplitude and Intensity Variables

• Voice Disorders• Neurological Disorders

Speech Acoustics 2

Frequency Variables

• Average Fo.• Fo frequency Variability• Maximum Phonational Frequency Range

Speech Acoustics 3

Frequency Variables continued

• Average Fundamental Frequency– Variables

•Age and Gender– Infants (350 to 500 Hz)– Ages 3 through 10 (270 to 300 Hz)– Adults

» Males (120 Hz)» Females (220 Hz)

•Individual differences

Speech Acoustics 4

Frequency Variables continued

• Frequency Variability– Normal SD is plus/minus 20 to 35 dB– Variables that affect variablity

• Emotions• Fatigue• Different grammatical constructions• Individual differences• Age (decreases through lifetime)• Neuromuscular or other disorders

– Frequency variability can be used as a baseline when examining different voice disorders

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Frequency Variables continued

• Maximum Phonational Frequency Range (MPFR)

• Differs from Fo which refers to connected speech.

• MPFR is the range of frequency that you can produce (provide example).

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• Mean MPFR is around 2.5 octaves or 30 semitones.

• Not a great deal of variability for age and gender.

• Trained singers have higher MPFR.

• Poor physical condition regardless of age may signal a problem with the speaker.

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Amplitude and Intensity Variables

• Average Amplitude Level• Amplitude Variability• Dynamic Range• Voice Range Profile

Speech Acoustics 8

AmplitudeVariables continued

• Average Amplitude Level– Refers to normal conversational levels

– Usually around 65 to 80 dB SPL (or 45 to 60 dB HL)

– No major age or gender effects.– May increase in background noise (Lombard effect)

– Lower amplitude may be a result of a pathology.

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• Amplitude Variability– Changes in amplitude due to …

• Speaker’s mood and feeling• Message such as stress, duration, syllabic structure, etc.

– SD is around 10 dB, but varies depending upon level of excitement.

– Lack of amplitude variation = monotone, and may be difficult to understand.

Speech Acoustics 10

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• Dynamic Range– Intensity difference between soft speech and the loudest shout.

– Normally between (30 and 115 dB SPL)

– Tends to be greatest for people with a near normal Fo.

– Trained signers may have greater dynamic range.

Speech Acoustics 11

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• Voice Range Profile– AKA VRP, phonetogram or FoSPL profile.

– Subject sustains a vowel at different Fos, and increases/decreases voice amplitude.

– Insert page 59.

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AmplitudeVariables continued

• Voice Range Profile continued– VRP can be used to get an overall picture of amplitude and frequency.

– Can be used to…• Determine normal vocal function• Monitor treatment for vocal disorder

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Voice Disorders

• Subjective measures– Perceptual Scales

• Objective measures– Amplitude– Frequency

• Use in monitoring progress of treatment

• Objective measures are more sensitive to changes.

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Neurological Disorders

• Examples include Parkinson’s Disease, amyotrophic lateral sclerosis (ALS), MS, strokes, brain tumors, TBI, etc.

• Objective measures can be used to track course of disease or treatment.

Speech Acoustics 15

Summary