Introduction:
Nasality is a voice upset that is most normally met by the address linguisticcommunicationdiagnostician in topics with repaired cleft roof of the mouth, which affects the address intelligibility. The perceptual appraisal of nasality constitutes an of import facet of a comprehensive appraisal of the address of persons with repaired cleft roof of the mouth and/or velopharyngeal disfunction ( Kuehn & A ; Moller, 2000 ) . The perceptual appraisal in complex populations like cleft roof of the mouth is made more ambitious by the many-sided nature of voice ( Bzoch, 1979 ) . The comparative impact of changing constituents of the voice ( e. g. , pitch, volume, resonance ) can farther act upon the signal perceived by a hearer ( Zraich, 1999 ) . In add-on the diverse array of perceptual appraisal of nasality has some troubles including the definition of footings, dependability and the usage of different types of graduated tables ( Kreiman, Gerratt, Kempster, Erman, & A ; Berke, 1993 ) .
Several invasive techniques are used clinically to image velopharyngeal port. Inactive sidelong radiogram are used to see the velopharyngeal structures during sustained sounds ( Hirschberg, 1986 ) . Multiview videoflouroscopy allowsobservationof the constructions during connected address from several planes of infinite. Flexible fiberoptic nasoendoscopy allows direct observation of velopharyngeal motions during connected address. However, these techniques appear to hold more value as pre- or post-surgical appraisal, because the correlativity of the informations from these techniques with hypernasality is frequently hapless. The inclusion of quantitative measurings in a clinical appraisal battery would lend to the overall truth of an probe. Literature reveals several quantitative methods developed to mensurate facets of rhinal resonance, for illustration, the Nasometer ( KayPENTAX, Lincoln Park, NJ ) , the Oro-Nasal System ( Glottal Enterprises, Syracuse ) or the NasalView ( Tiger DRS, Inc. , Seattle, WA ; Bressmann, 2005 ) , Horii Oral-Nasal Coupling Index ( Horii, 1980 ) , Sonography ( Dillenschneider, Zaleski & A ; Greiner, 1973 ) , Palatal Efficiency Ratings Computed Instantaneously-Speech Aeromechanics Research System ( PERCI-SAR ; MicroTronics Corp. , Chapel Hill, NC ) . The application of these instruments is frequently limited by a combination of grounds, including a deficiency of comparative surveies straight contrasting each technique, clinical uncertainity associating to the sensitiveness and specificity of viing methodological analysiss, the popularity of imaging surveies ( typically, nasoendoscopy and videoflouroscopy ) that provide direct information on velopharyngeal inadequacy ( Bekir et al., 2008 ; Rowe & A ; D’antonio, 2005 ) and the demand of specific device and/or detector, such as the helmet required for nasalence, the accelerometers required for HONC, the aerophonoscope required for rhinal emanation sensing and frequent standardization of the instruments.
Nasality can besides be evaluated utilizing non-invasive and simple processs like, spectral analysis of speech signal. Acoustic techniques frequently entail arduous analysis governments that can necessitate extended user expertness ; the rightness of selected stimulation has non been strictly evaluated ( Watterson et al, 2007 ) . Acoustic techniques do offer some possible, as small expertness is required to enter address samples, and repeated samples can be easy obtained, doing acoustic techniques appropriate for curative pattern.
Some of the spectral features associated with hypernasality are reduced strength of the first format ( F1 ) , the presence of excess resonance, displacements of the Centre of the low-frequency spectral prominence, increased amplitudes of the sets between first formant ( F1 ) and the 2nd formant ( F2 ) , and a lessening of the F2 amplitude ( Curtis, 1968 ; Hawkins & A ; Stevens, 1985 ; Kataoka et Al, 2001 ) , increased continuances of acoustic phonic sections in CVC vocalizations ( D’Antonia, 1982 ) ; prolonged VOT ( Gamiz, Fernandez-Valades, 2006 ) and decreased burst continuance ( Vasanthi, 2000 ) , decrease in volume ( Mc Williams & A ; Philip, 1979 ; Vasanthi, 2000 ; Peterson-Falzone et al. , 2001 ) . In recent old ages, nasality is evaluated utilizing spectral analysis of the address signal. The two common methods which are reported in the nasality measuring literature are one-third octave spectra analysis ( Yoshida et al, 2000 ; Kataoka et Al, 2001 ; Lee et Al, 2009 ; Vogel et Al, 2009 ) and the Voice Low Tone to HHhhhhhhhhhhhhhhhhhjjkiuigh Tone Ratio ( Lee, Wang, Yang & A ; Kuo, 2006 ) . Both methods focus on strength fluctuation around the first, 2nd and 3rd frequence formants, an acoustic form normally seen in hypernasal address ( Chen, 1996 ; Huffman, 1990 ; Kent, Weismer, Kent, Vorperian & A ; Duffy, 1999 ) .
The Voice Low Tone to HHhhhhhhhhhhhhhhhhhjjkiuigh Tone Ratio ( VLHR ) was developed as a quantitative acoustic step based on the strength spectrum to measure rhinal resonance. Lee et Al ( 2009 ) defined the voice low tone to high tone ratio as the power ratio of the low frequence to high frequence energy obtained by spliting the voice spectrum with a specific cutoff frequence. Lee et Al, ( 2003 ) measured VLHR in topics with rhinal obstruction before and after intervention for rhinal congestion. Results revealed increased VLHR values significantly after decongested intervention. In the follow survey by same writers in 2006, obtained sustained vowels ( /a: / ) and a nasalized ( /a : / ) vowel from eight hypernasal grownups. The writers observed higher VLHR values in nasalized sounds than unwritten sounds, supplying farther grounds in support to the VLHR technique for measuring hypernasality.
Lee et Al ( 2009 ) measured VLHR in topics with hypernasality caused by palatine fistulous withers and velopharyngeal inadequacy for sustained vowels. The consequences of their survey revealed important differences between VLHR values, hypernasality tonss and nasalence steps. In contrast to the old surveies, Vogel et Al ( 2009 ) compared VLHR and one 3rd octave analysis in cleft roof of the mouth kids to mensurate hypernasality. Consequences revealed that merely one 3rd octave spectra analysis differentiated hypernasal address between cleft roof of the mouth and normal kids. The difference obtained between these two surveies ( Lee et al, 2009 ; Vogel et al. , 2009 ) may be because of the methodological analysis employed to pull out VLHR and the pathological status and age of the topics participated in their survey. Sing all these factors the efficaciousness of non-invasive technique, like VLHR to measure hypernasality remains inconclusive in clinical population like Cleft lip/palate.
Need FOR THE PRESENT STUDY:
Very few surveies have been conducted to mensurate the nasality in cleft roof of the mouth topics utilizing VLHR. But, the consequences of these surveies are inconclusive and necessitate farther probe in other linguistic communications besides. Hence, the present survey was aimed to observe the differences in VLHR between cleft roof of the mouth and normal topics utilizing address samples collected in Malayalam linguistic communication.
AIM OF THE PRESENT STUDY:
The present survey was aimed to observe the differences in VLHR between cleft roof of the mouth and normal persons for voice undertaking, word list undertaking and transition reading undertaking.
Methodology
Subjects: A sum of 40 immature grownups within the age scope of 17 to 26 old ages participated in the survey. They were divided into two groups. Group I consisted of 20 cleft roof of the mouth persons ( 10 males and 10 females, average = 19 old ages ) . They were included in the survey if they had a diagnosing of inborn cleft roof of the mouth, undergone primary surgery to mend the cleft roof of the mouth, and go toing or had been referred for address therapy. Group II consisted of 20 normal, age and gender matched control topics.
The topics were screened for address, linguistic communication and hearing by speech linguistic communication diagnostician. All the topics were native talkers of Malayalam linguistic communication. Subjects with a upper respiratory piece of land infections, blocked nose or with rhinal congestion as assessed during the oro-motor scrutiny were excluded from the survey.
Test Material: The stuffs involved three different assortments of address samples ( 1 ) sustained voice samples ( /a: / , /i: / and /u: / ) ; ( 2 ) six meaningful words selected from Malayalam Articulation Test ( Mayadevi, 1990 ) which consisted of force per unit area consonants and ; ( 3 ) a standard Malayalam Reading Passage ( Anita, 1999 ) were used.
Instrumentality: The recordings were carried out at address scientific discipline research lab of the infirmary. The address samples for the survey were recorded utilizing Sony digital recording equipment ICD-U60 placed 10 centimeters off from the talker ‘s oral cavity. This recorded address samples were fed into the Praat package ( Version 5. 1. 43 ) digitally and sampled at 16K Hz, 12 spot quantisation and Praat book was used to pull out the VLHR parametric quantity.
Procedure: All participants were instructed to bring forth three tests of sustained vowels ( /a: / , /i: / and /u: / ) for a minimal continuance of 5 sec ; six selected word list from Malayalam Articulation Test ( Mayadevi, 1990 ) and to read a standard Malayalam Reading Passage ( Anita, 1999 ) at their comfy pitch and loudness degree. A sum of 720 ( 3 vowels*6 words*1 sentence*40 topics ) items were acoustically analyzed to pull out VLHR parametric quantity.
The voice spectra was derived utilizing fast fourier transform ( FFT ) with Praat package for all the address samples recorded and averaged for farther analysis. Acoustic information was analyzed in conformity with the prescribed protocols for VLHR ( Lee et al. , 2006 ; 2003 ) . VLHR was calculated by spliting the spectrum into a low frequence power subdivision ( LFP ) and a high frequence power subdivision ( HFP ) . The mean spectrum was divided into low frequence and high frequence parts utilizing a cutoff frequence of 600 Hz by utilizing Praat book ( Lee et al, 2009 ) . The equation for VLHR is as follows: VLHR= 10 A- log10 ( LFP/HFP ) . VLHR was used to cipher values on sustained vowel undertakings ( /a: / , /i: / , /u: / ) , six meaningful words and a sentence from standard transition were used and it was expressed in dubnium.
Statistical analysis: The information was subjected to statistical analysis utilizing SPSS ( Version 17 ) . The mean and standard divergence values of VLHR for address samples were calculated and tabulated for each topic. Analysis of Variance was used on the information to find the important difference between the groups and address samples.
Consequence:
VLHR for voice undertaking: For voice undertaking, the average VLHR values for /a/ , /i/ & A ; /u/ was 12. 79 dubnium, 16. 79 dubnium and 16. 81 dubnium for topics with cleft roof of the mouth and for normal topics it was 4. 14 dubnium, 9. 59 dubnium and 6. 93 dubnium severally. Consequences showed that high forepart vowel /i/ had the highest VLHR value followed by high back vowel /u/ and low mid vowel /a/ for both the groups. Table 1 and Graph 1 depicts the mean and SD of VLHR. Results of ANOVA indicated important difference between group I and group II subjects for all the vowels ( F= 50. 389 ; p= 0. 000 ) .
Voice undertaking
Group I
Group II
F value
Mean
South dakota
Mean
South dakota
/a/
12. 79
2. 15
4. 14
2. 86
F= 50. 389
P & lt ; 0. 005
/i/
16. 7
3. 61
9. 59
2. 51
/u/
16. 81
4. 83
6. 93
4. 32
Table 1: Mean and SD VLHR values for group I and group II subjects for voice undertaking.
Graph 1: Represents the average values of voice undertaking for /a/ , /i/ and /u/ for Group I and Group II subjects.
VLHR for word list: Table 2 represents the mean and SD values of VLHR for words for cleft roof of the mouth and normal topics. In word list undertaking, the mean VLHR value for dissected roof of the mouth topics was 10. 21 dubnium and for normal topics it was 3. 53 dubnium. Consequences showed higher average VLHR values for cleft roof of the mouth topics than the normal capable values for all the words selected for the survey. On statistical analysis, consequences revealed a important difference between groups ( F= 60. 34 ; p= 0. 000 ) .
Word List
Group I
Group II
F value
Mean
South dakota
Mean
South dakota
Word 1
11. 70
4. 20
5. 47
3. 5
F= 60. 34
P & lt ; 0. 005
Word 2
9. 422
4. 56
3. 55
1. 84
Word 3
10. 69
4. 86
2. 70
1. 82
Word 4
11. 26
5. 01
2. 94
1. 30
Word 5
9. 14
4. 92
2. 55
2. 02
Word 6
8. 88
3. 29
3. 96
2. 38
Overall Mean
10. 21
4. 58
3. 53
2. 47
Table 2: Mean and SD VLHR values in dubnium for group I and group II persons for word list undertaking.
Graph 2: Represents the average values of word list undertaking for group I and group II subjects.
VLHR for transition reading: For transition reading undertaking, the mean VLHR value for dissected roof of the mouth topics was 9. 68 dubnium and for normal topics it was 2. 31 dubnium. Table 3 and Graph 3 shows the VLHR values for transition reading undertaking for group I and group II subjects. Consequences showed important differences for groups ( F= 48. 54 ; p= 0. 000 ) for transition reading.
Passage reading
Group I
Group II
F value
Mean
South dakota
Mean
South dakota
9. 68
2. 31
F= 48. 54 ; P & lt ; 0. 005
Table 3: Mean and SD VLHR values in dubnium for group I and group II persons for transition reading undertaking.
Graph 3: Represents the average values of transition reading undertaking for group I and group II subjects.
Discussion:
Vowel /a/ had important lower VLHR values compared to vowel /i/ and /u/ . This consequence of the present survey supports the findings of Neumann & A ; Dalston, 2001 and Lewis et Al, 2000. The higher VLHR values obtained may be due to the articulatory positions assumed during the production of these vowels. The low mid vowel /a/ is a unfastened vowel which creates comparatively small opposition to airflow out of the oral cavity. Therefore the maximal energy is transmitted through the unwritten pit and therefore comparatively lower VLHR values compared to vowel /i/ and /u/ values ( Lee et al. , 2009 ) . Whereas in instance of cleft roof of the mouth persons because of velopharyngeal insufficiency there might be more of nasal energy flight which is indicated through the higher VLHR values than normal topics for voice undertaking. The consequences besides support the findings of Moore & A ; Sommers ( 1973 ) who reported the greater grade of nasality on high vowels as the high vowels make greater demand upon the valving map i. e. , higher points of posterior guttural wall/ velar contacts, tighter velopharyngeal seals and greater velar jaunt.
Higher VLHR values obtained in dissected roof of the mouth topics were similar to other surveies. Similar consequences were obtained in topics with rhinal obstruction after intervention for rhinal congestion ( Lee et al, ( 2003 ) , in palatine fistulous withers and velopharyngeal inadequacy topics ( Lee et Al ( 2009 ) . The consequences of their survey revealed higher VLHR values and important differences between VLHR values, hypernasality tonss and nasalence steps. In contrast to the old surveies, Vogel et Al ( 2009 ) compared VLHR and one 3rd octave analysis in cleft roof of the mouth kids to mensurate hypernasality. Consequences concluded that merely one 3rd octave spectra analysis differentiated hypernasal address between cleft roof of the mouth and normal kids. The major difference obtained between these two surveies ( Lee et al, 2009 ; Vogel et al. , 2009 ) may be because of the methodological analysis employed to pull out VLHR and the pathological status and age of the topics participated in their survey.
The ground attributed for higher VLHR values for word list and transition reading undertaking may be due to the acoustic characteristics of the pharyngeal topographic point of articulation, notably low frequence noise energy chiefly in the chief formant part ( i. e. , the part of F1 and F2 ) . The form of the vowels was non good defined, peculiarly because nasaliztion has greatly reduced the amplitude of F2 so that this formant is hardly apparent in the spectrograph. Another common site of articulative compensations, the voice box, besides tends to be associated with acoustic energy in the chief formant part. Thus both guttural and laryngeal compensation contribute to comparatively low-frequency acoustic construction for consonants. These speech compensations hence are characterized by diminished or absent cues in some spectral parts but by extra cues in other spectral parts.
Overall survey consequences showed statistical important difference between the groups for all the address samples collected. The average VLHR values in dubnium were higher for cleft roof of the mouth topics compared to that of normal topics. The consequences are in consonant rhyme with the findings of Lee et al. , ( 2003 ; 2009 ) whereas in disagreement with Vogel et al. , ( 2009 ) . The higher VLHR values obtained in the present survey may be attributed to the belongingss of increased low frequence energy i. e. , rhinal formant and reduced high frequence energy i. e. , anti resonance of rhinal voices in cleft roof of the mouth topics because of velopharyngeal insufficiency which was absent in normal topics ( Chen, 1996 ; Kent, Weismer & A ; Duffy, 1999 ) . Thus addition in the amplitude of frequences between F1 and F2 every bit good as lessening in the amplitude above F2 have been linked to hypernasality and these alterations were thought to be captured via VLHR ( Lee et al, 2009 ) .
Decision:
The purpose of the present survey was to observe the differences in VLHR for address samples between cleft roof of the mouth and normal topics. Consequences revealed that the VLHR values were higher for cleft roof of the mouth topics for all the address samples analyzed. The important difference obtained may be because of the belongingss of increased low frequence energy and reduced high frequence energy of rhinal voices in cleft roof of the mouth topics. Hence, we conclude that VLHR parametric quantity is sensitive plenty to observe rhinal voices in cleft roof of the mouth topics and can be implemented as a everyday clinical tool for nasality measuring. And besides the sensed success of surgical or curative intercession in dissected palate topics can be measured quantitatively with the VLHR parametric quantity extraction. Further surveies can be carried out with more figure of participants and besides in other Indian linguistic communications to set up normative.
