DIFFERENTIAL DIAGNOSIS Flashcards
Signs
Sign (can be observed or tested):
Hoarseness (low fundamental frequency, reduced variability of fundamental
frequency, increased frequency perturbation, increased spectral noise, and
large s/z ratio.
Provide objective information-how signs relate to each other and underlying
pathology will help SLP and otolaryngologist evaluate its significance
Acoustics
What do vocal acoustics give us ?
Acoustics is the study of sound, and voice acoustics gives us
information about the way our vocal folds move.
Acoustic signs tell us some aspect of the underlying pathology.
Acoustic parameters are easy to record and analyze
objectively.
Visi Pitch
Computerized Speech Laboratory
Dr. Speech
Praat
Fundamental frequency:
Vibrating frequency of the VF’S is known as fundamental frequency.
Mean Fundamental frequency:
Lots of normative data available
Frequency variability
Frequency variability
Standard deviation of fundamental frequency reflects
frequency variability for a time segment of passage.
The standard deviation of fundamental frequency for
the sentence of normal speaker in example was 27.97
Phonational range:
What’s a normal phonational range ?
Phonational range:
Is the range of frequencies that a person can produce.
Normal patients should have a phonational range of about 3 octaves. These
decrease with age and increase with singers
Frequency perturbation (jitter):
Frequency perturbation (jitter):
measures the variability of the fundamental frequency of the vocal fold tone
from one cycle to the next (Baken & Orlikoff, 2000).
Individuals with normal voice have a small amount of
Individuals with normal voice have a small amount of
perturbation.
Increased frequency perturbation is an acoustic correlate of
erratic vibratory patterns of the vocal folds, which is indicative
of a voice disorder (Beckett, 1969)
Amplitude
What does the amplitude tell us?
Amplitude
Strength of the tone
Overall sound pressure level
Average overall SPL (dB) gives us an idea of the strength of the vocal fold
vibration. Everyday speech has a range of 70-80 db (Baken & Orlikoff,
2000)
Amplitude Variability
Amplitude Variability
The amplitude varies depending on the sounds spoken and the message you want to convey.
Amplitude variability during speech is expressed as a standard deviation.
Dynamic range
Dynamic range
The range of vocal intensities that a person can produce (50-115dB). Males
intensity higher than female
Amplitude Perturbation(shimmer)
Amplitude Perturbation(shimmer)
o Measures how much the peak amplitude of the vocal fold tone will vary from one cycle to the next
(Titze, 1994).
o Similar to frequency perturbation values, amplitude perturbation values quantify short term
amplitude instability (Baken & Orlikoff, 2000). Vocal fold growths or neural control issues affect
stability of VF which is reflected in shimmer values.
Signal to noise ratio
5
Signal to noise ratio
Normal voices have low noise levels, while abnormal voices have higher
levels of noise
Voice tremor
Phonation time
Voice Stoppages
Frequency Breaks
Normal Acoustics
Perceptual signs of voice problems
Pitch
4
Monopitch (reduce pitch variability )
Inappropriate pitch
Pitch breaks
Reduce pitch range
Perceptual signs of voice problems
Loudness
3
Monoloudness (reduced loudness variability)
Loudness variation (soft, load or uncontrolled)
Reduce loudness range
Perceptual signs of voice problems
Quality
Hoarse or rough
Breathy
Tension
Tremor
Strain or struggle
Sudden interruption of voicing
Diplophonia
