Nasalance Nasalization 3 7 00 Velopharyngeal Function Nasality

Nasalance/ Nasalization 3/7/00

Velopharyngeal Function • Nasality & nasal emission of air are symptoms of many speech disorders – Cleft palate, dysarthria, dyspraxia, hearing impaired • Nasalization is the existence of significant communication between the nasal cavity and the rest of the vocal tract

Velopharyngeal Function • Inappropriate nasalization– Causes, 1) Nasal emission (abnormal escape of air via the nose); 2) Nasality (Hypernasality)unacceptable voice quality that results from inappropriate addition of the nasal resonance to the vocal tract – Nasality does not involve large nasal airflows or change intraoral air pressure like nasal emission

Nasality • Reliably perceived • Perceptual attribute- requires judgement of a listener • Mostly a function of velopharyngeal port opening size • Vowels have different levels of nasality (low vowels-high nasality; High vowelslow nasality) • So, don’t use an isolated vowel to judge nasality

Testing Decisions • Difficulty in determining differences between velar and pharyngeal function • No linear relationship between size of velopharyngeal opening and level of nasality • Nonspeech tasks are poor indicators of VP function- sucking and impounding intraoral air pressure can be accomplished by linguapalatal valving

Testing Decisions • Nonspeech functions cont. -Cleft palate patients who can’t achieve VP closure during speech, routinely do during swallowing • Measurement of static tasks (i. e. sustained vowels) differ from speaking tasks- timing is not being tested

Instrumentation- VP • Electromyography- not suitable for clinical use • X-Ray techniques- visualization of palatal activity • Sound Spectrography • Airflow measures

Ideal Measurement Criteria • Noninvasive • Assess VP function during speech • Nondisruptive of respiratory, ventilatory or articulatory function • Excellent correlation with perceived nasality • Low cost • Ease of interpretation

Visualization of Palatal Structures • Endoscopy- telescopic device to visualize velar function – Oral Panendoscope • Disadvantages: – Gagging – Articulation is compromised – Fiberoptic Endoscope • Viewing of VP from above • More invasive than panendoscope

Indirect Assessment Methods • Articulation tests – Distortion on high pressure consonants for inadequate closing – Distortion on nasal sound for inadequate opening – IPAT (Iowa pressure articulation test) • Disadvantages– Articulation problems may not be due to VPI

Indirect Assessment Methods • TONAR (oral nasal acoustic ratio): Nasometer – Two microphones (nasal and oral) – Nasal and oral amplitude – Ratio of nasal to oral output = nasalance – Nasalance has been found to correlate moderately with perceived nasality

Laboratory • Nasometer– Nasal sound pressure/oral sound pressure= nasalance – 0 -100% Nasality- more nasal airflow the higher the ratio becomes • Part I– Record amount of nasalance for /m/ – Normal? – What might give you low nasalance?

Laboratory • Part I cont. – Record amount of nasalance for /a/ – Normal? – What might give you high nasalance? – Measure nasalance from figure A for /m/ and /a/ and compare to your measures. – Now, produce /æ/, /i/ and /u/ in time history display- describe differences in mean nasalance – Why might mean nasalance differ between vowels?

Laboratory • Part II- Use Nasometer! – Repeat /ma/ syllable at moderate • • Mark the vowels and consonants Mean and SD nasalance for the whole sample Mean nasalance for vowel and for consonant How do they compare to the isolated production of /m/ and /a/ earlier?

Laboratory • Part II- Use Figure B – Resonance disorder (hyper or hyponasality) repeated sample of /ma/ syllable at comfortable rate • Compare to previous sample of syllable train • Mean and SD nasalance for entire sample • Mean of vowel and consonant productions – Compare to previous speaker – Consistent of variable nasalance record compared to other speaker

Laboratory • Part II- Use Nasometer! – Normal speaker repeating /ba/ syllable at comfortable rate • Mark each vowel and consonant • Mean and SD nasalance for entire sample • Mean of vowel and consonant productions – Compare to previous speaker – Why might you see different vowel nasalance when compared to /ma/

Laboratory • Part II- Use Nasometer!! – Normal speaker mean nasalance for sentences • “Mama made some lemon jam” • “Please put the five cupcakes back” – Use Figure C: Take same two sentences and repeat by a person with a resonance disorder • Assess differences between patients

Laboratory • Part II- Use Figure D – Locate each phone • /a. I/, /t/, /a. I/, /dð/ /e/, /b/, /e. I/, /I/ – Regions of nasal flow – Fill in table of nasal flow during each phone – From the record what is the relationship of nasal flow during high Pio?

Laboratory • Part II- Use Figure E – Use sample- “I tend the mail” • • • Mark each phone Areas of significant flow Measure nasal flow and Pio during each phone Is nasalization limited to the nasal phones /n/ & /m/? Why might their be hypernasality in the normal speaker?

Laboratory • Part III- Use Figure F – Velopharyngeal timing – Relationship between nasal flow & Pio-describe this child’s VP function