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APRAXIA OF SPEECH

Variable errors, noticeable over repeated production of words

Self correction and awareness of errors

Intrusive schwas

Syllable segmentation and syllable lengthening

Slow rate and abnormal prosody

APRAXIA
DYSTONIA
HYPOKINETIC
ATAXIA
SPASTIC
FLACCID
BASICS
TREMOR

SPEECH BASICS

Pitch: Frequency of the fundamental harmonic. The pitch is determined by the vibration of vocal cords. The pitch of female speakers being on the average twice as high as that of male speakers.

 

Timbre: Relative height of the frequency of speech in the power spectrum

 

Loudness: Overall height of peeks in power spectrum.

 

Prosody: Variation in loudness, pitch, and timing accompanying natural speech. This is measured by F0 SD:  Standard deviation of fundamental frequency (F0), representing the variations of vibration rate of vocal folds.

 

Jitter: this is the measure of the variability of the speech fundamental frequency (pitch period) from one cycle to the next.

Shimmer: This is the measure of amplitude variability within each vocal cycle. Jitter and shimmer are measures for assessing the micro-instability of vocal fold vibration.

Formant: Formants distinguish one vowel from the other. Formants are produced by vocal tract resonances and their frequency depends on position of the tongue with respect to palate.

 

Consonant classification:

1. Plosive or stop (p, t, k) - produced by blocking the flow of air.

2. Fricative (f, s, sh, h, v) – These are produced by making the airflow constricted to create turbulence.

3. Nasal (m, n) – produced by lowering the soft palate

4. Liquid (l, r) – produced by raising tip of tongue.

 

Diadochokinetic (DDK) task:

  1. Alternating Motion Rate (AMR) involves a single syllable being repeated at maximum rate. Syllables pa, ta, ka are used individually for AMR.

  2. Sequential Motion Rate (SMR) involves a sequence of syllables is repeated at maximum rate. ‘pataka’  is used for SMR.

 

Syllables are repeated at a constant rate and long as possible (at least five times). They have been shown to correlate with perceptual ratings of severity and intelligibility in dysarthria. A single trial may be sufficient, as DDK tasks have high test-retest reliability.

Harmonic to noise ratio (HNR): HNR is a measure of quality of speech. Harmonics-to- noise (HNR) ratios are derived from the signal-to-noise estimates from the autocorrelation of each cycle and are used for assessing voice hoarseness. Low HNR (<20DB) is suggestive of a hoarse voice.

Pulse: Pulse is one opening and closing cycle of vocal cord.

Number of voice breaks: Over all count of voice breaks. Defined as distance between consecutive pulses longer than 1.25 divided by bottom of the pitch range. (if the pitch bottom is 100 hz then it would be 1.25 x 1/100 = 1.25 x 10 msec = 12.5 msec. ie the next pulse was delayed by  2.5 msec)

Degree of voicelessness (DUV): DUV is a measure of breaks in the sustained phonation. Spastic voice has a strained and strangled quality and is usually associated with effortful squeezing of air during passing through glottis. The strained-strangled voice is assumed to arise from over closure of vocal folds during the production of vowels and can be measured by the parameter DUV. Similarly in ataxic speech increased DUV or pitch breaks are commonly seen. DUV are the fraction of pitch frames that are analyzed as unvoiced. It is measured by sustained phonation

HYPOKINETIC SPEECH

Reduced Prosody (Monopitch)

Low volume

Tachyphemia: Delayed Auditory Feedback (DAF) and metronome may help in reducing he rate of speech

Speech analysis:

Airflow insufficiency (Maximum phonation time (MPT))

Harsh voice (Jitter, shimmer and HNR)

Rapid AMR (DDK rate)

Reduced loudness (Mean speech intensity in monologue)

Monopitch (F0 SD) in Monologue

F0 (Pitch) Curve: In PD there is loss of F0 rise and peaks and flatting of f0 curve.

DYSTONIA OF SPEECH

Adductor dystonia

85% of cases of vocal cord dystonia

breaks due to hyper-adduction of vocal cords resulting in a quick glottic closure interrupting airflow

Use sentences that have several glottal stops (rapid onset of voice) 

Use voiced sentences:

" We eat eels everyday'

"We mow our lawn all year"

"We eat eggs ever Easter" 

Abductor dystonia

Breathy effortful voice with abrupt breaks

whispering elements of speech due to prolonged abduction during voiceless consonants (/h/,/s/,/f/,/p/,/t/,/k/).

Use sentence:

"The puppy bit the tape"

ATAXIC SPEECH

Excess and equal stress on syllables

Irregular articulatory breakdown

Prolonged phonemes (Scanning speech)

Speech analysis:

Excess pitch fluctuations in sustained phonation (F0 SD)

Vocal tremor

Irregular AMR

Prolonged phonemes

Excess intensity variations in monologue (Intensity SD)
F0 (Pitch)Curve: Ataxic speech demonstrates breaks in F0 curve.

SPASTIC SPEECH

Bilateral UMN lesions

Strained-strangled voice

Slow AMR

Slow speech rate

Low pitch voice

Speech analysis:

Normal HNR (Harmonic to Noise Ratio)

High Jitter and Shimmer

High pitch variability

Strained-strangled voice (DUV)

Slow AMR (DDK rate)

Slow speech rate (words/ sec)

PHONATION_DIPLOPHONIA
00:00 / 00:10
ADD SPAS DYSPHONIA
00:00 / 00:22

FLACCID SPEECH

Breathy voice (Adductor weakness)

Breathiness is noise quantified by HNR

Audible respiration

Patient uses short phrases

Mono loudness and Mono pitch

May have Diplophonia ( Double pitch)

Usually seen in unilateral vocal cord palsy

AMR is usually normal to fast

Hyper nasal voice:

More low frequencies as high frequencies are filtered

PaPaPa or BaBaBa sound like NaNaNa or MaMaMA

Speech analysis:

High HNR (Harmonic to Noise Ratio)

Normal Jitter and Shimmer

Diplophonia

Airflow insufficiency (Maximum phonation time (MPT))

TREMOR

Vocal cord, jaw, tongue, lip or respiratory muscle tremor.

In a patient with diffuse cerebellar atrophy and presenting with audible voice tremor, Fundamental frequency contours during sustained phonation of vowels showed rhythmic oscillations at a rate of about 3 Hz. This may indicate an impairment of phonatory control by maintaining a constant isometric activity of the internal laryngeal muscles.

 

Method:

Speech testing included sustained phonation on /u/ and /a/ or sustained production of voiceless fricatives /f/, /sh/, /s/ as long as possible on a single breath

 

Vowel production tasks examine the patient's faculty of maintaining a stable laryngeal configuration

 

Fricative task requires the maintenance of stable articulatory configurations of lips and jaw (/f/), tongue blade and jaw (/s/), and tongue dorsum and jaw (/sh/), respectively.

 

In both tasks, a constant transglottal flow must be maintained through respiratory control. Respiratory muscle will be present in all above tasks.

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