The Challenges Faced by People with Cochlear Implants as It Relates to Prosody - Research Paper Example

Prosody in speech perception and speech production (cochlear implants) In the field of speech and language pathology, children who have received a cochlear implants have been studied extensively . In recent years, prosody as it relates to speech perception and production, has been looked upon, and the consensus among the researchers is that more research is necessary on prosody. Some of the critical challenges faced by these researchers are as follows: Sample size Previous researches have used 5-8 participants in their research. With a sample as small as this, it is hard to fully observe the patterns and the trends and does not ensure the inclusion of the various regions of the U.S.A. Length of study: The other critical issue faced by researchers is the length of time needed to conduct these studies. Some of the studies have been over a long period of time because children take great amount of time to get comfortable with the device and to start benefiting from it. This paper will attempt to explain some of the challenges faced by children fitted with cochlear implants as regards to prosody, which impacts their ability to perceive as well as to produce speech. More challenges faced by Researchers Before a child/adult gets implanted with the device, the first stage is where the child has to wear a hearing aid and then he is implanted with cochlear implants. In case of a deaf child, the hearing aid proves ineffective and does not help the child hear better. Furthermore, with cochlear implants an essential issue that researchers focused on is the issue of the critical period. When referring to the critical period, there are two key words to consider: One is pre-lingual implantation and the other is post-lingual. In essence, the term pre-lingual refers to the period before the child acquires the language. The term post-lingual refers to the period after the child acquires language. Various researchers agreed that the earlier the child gets cochlear implants (CI), the better as it helps the child to learn the language more effectively. Another key component that requires further research is the area of prosody. Over the years, various researchers looked at prosody and concluded that device was not designed properly enough to perceive certain aspects of prosody such as pitch, intonation, loudness etc. It is not until researchers started closely examining speech patterns of individuals with the device that they realized that prosody is greatly affected. The other key argument that was also made is whether or not sufficient linguistic exposure with the device can improve prosody. Prosody In the field of communication disorders , prosody refers to rhythm, stress and intonation of connected speech. Sometimes, prosody reflects the speaker’s emotional state. For e.g. if a person is sad or upset, it affects the way the message is conveyed. (Lenden & Flipser Jr., 2006, p. 67). Other times it may reflect a focus point such as an interjection, a question or a command. (Lenden & Flipser Jr., 2006, p. 67). It is important to mention that prosody is not involved in writing. That is one of the reasons why a text message can be misunderstood or can be perceived as ambiguous at times. In reference to acoustic features , changes in any of them such as fundamental frequency , intensity, duration, and spectral characteristics can affect how the message is perceived, which in turn can affect speech production. (Lenden & Flipser Jr., 2006, p. 67). Prosody in speech production Lenden and her colleague compared prosody and voice characteristics of children suffering from hearing impairment with children fitted with cochlear implants. In 1990, Shriberg, Kwiatkoski, and Ramussen identified seven broad dimensions of speech that have been observed to contribute to a speaker’s severity of involvement (p.22). They studies the essential facts that affect the degree of prosody (phrasing, rate, stress) and voice (loudness, pitch, laryngeal quality, resonance quality). These factors proved to pose various challenges for individuals with hearing impairment who have not yet had the benefit of cochlear implants (as cited in Allen & Arndorfer, 2000; Boone 1996, 1971; Calvert, 1962). The conversational pattern of a person with cochlear implants does not follow a rhythmic pattern. Lack of linguistic exposure can be one of the causes that affects the flow of speech (as cited in Shriberg, 1990). In their study, they also noted that individuals with hearing impairment tend to produce each word separately and not in a continuum as people with normal hearing produce (as cited in Boone, 1966). These findings are consistent with studies that explained that co-articulation posed a serious problem for people with a hearing impairment (as cited by Okalidou & Harris, 1999). Other researchers have long reached similar conclusions by reporting poorly blended sounds in words with this population (p. 68). Another area of prosody that peaked their interest is a stress . Lenden & Flipser Jr. (2006) studied stress and pointed out that a stress refers to the lexical, phrasal, as manifested using changes in pitch, loudness or intensity (as cited in Shriberg, 1990). Individuals with hearing impairment were observed to use unrelated stress patterns (as cited in Hargrove, 1997; Subtelny et al., 1980). They noted that it is almost as if individuals with hearing impairment only produce stress syllables (p. 68). Lenden and & Flipster Jr.(2006) described the speech of individuals with hearing impairment as monotonous because of a lot of changes in pitch. (as cited by Nickerson, 1975). Another component that is looked at is voice parameters ; loudness is also a main source of problem for individuals with hearing impairments (as cited in Smith, 1975). Lenden & Flipster Jr. also observed that deaf individuals may simply not be unable to speak loud enough in a given situation ( as cited in Silver, 1983). The other aspect that is addressed is pitch. They noticed that there is not much vocal pitch variation in individuals with hearing impairments. They perceived them to be monotonous and observed excessive changes in their speech such as diplophonia (as cited in Monsen, 1978; Parkhurst & Levit, 1978; Smith, 1975; Subtelny et al., 1980). Also abnormal pitch has also been noted in the speech of hearing impaired (as cited in Boone, 1966; Stathopoulos et al., 1986). Lenden and Flipster Jr. Also have noted that severity of hearing impairment appear to play a relative role in pitch (as cited in McGarr and Osberger 1978).Another key component that was studies is the overall vocal quality (along with loudness, pitch and resonance quality) (as cited in Shriberg 1990). The authors described the speech of individuals with hearing impairment as tense, flat, breathy, harsh and throaty(as cited in Calvert, 1962). Also, much force on stops before a vowel is common in the speech of a person with hearing problem. It can also result in a breathy voice quality (as cited in Calvert & Silverman, 1983, p.169). Consequently, Lenden & Flipster Jr. explained that a breathy/weak voice could be a result of poor adduction, and a lot of strain from over-adduction, which can result in an overall tense/strained voice quality (as cited in Subtelny et al. 1990). Finally, the quality of resonance plays an important role in the speech of hearing impaired individuals. Lenden and Flipster Jr. A (2006) characterized production by a pharyngeal focus resonance; terms as a hollow (as cited in Boone, 1971), cul-de-sac resonance or a hot potato voice (as cited in Finkelstein et al., 1993) have been applied. Lenden & Flipster (2006) observed a hyper- and hyponasality in hearing impaired people’s speech (p. 68). They also explained that hearing impaired people have more nasal quality in their speech than normal hearing speakers. (as cited in Fletcher et al. 1999). As explained throughout the paper much is known about the prosody as it relates to speech production of hearing impaired children. However, the research is a bit more limited with cochlear implants. Lenden and Flipster Jr.(2006) have compared the voice characteristics of hearing impaired individuals with the hearing impaired population who have been implanted with cochlear implants. However more research is warranted. It is important to point that children with cochlear implants with single channel appears to perceive intonation patterns more readily than the number of syllables or syllable stress in a word (as cited in Carney et al., 1990). A Lenden & Flipster Jr. (2006) noted that after 1 year of cochlear implant experience, speakers were better able to imitate the prosodic features of speech as tested by the Phonetic Level Speech Evaluation (as cited in Fletcher et al. 1999; Ling et al. 1966).A It is important to mention here that previous studies have not focused directly on prosody and voice characteristics but on brief mention findings that are related to speech perception and production. Lenden & Flipster Jr. (2006) in their study raised two prominent questions. They first considered whether or not children with cochlear implants have difficulties with suprasegmentals measured on the Prosody-Voice screening Profile (PVSP). Secondly, they considered the developmental trends on any of the suprasegmental measured on the PSVP (p.70). They set some guidelines for children participation and they are as follows: a) Prelingually deaf (defined as onset of hearing loss before age 3), b) Fitted with a multichannel cochlear implant by age 3 , c) Use of the cochlear implant for at least 18 months at the onset of testing d ) Use of speech only as their primary communication mode , and e) Receptive vocabulary as measured by the Peabody Picture Vocabulary Test-Third Edition (PPVT-III; Dunn & Dunn, 1997) within two standard deviations of their age group mean (i.e., a standard score at least 70). Only six children (five girls and one boy) satisfied their requirements and participated in the study. Some of the findings are very encouraging and some follow the same trends as previously anticipated by hearing impaired population who have not been fitted with cochlear implants . It is encouraging to know that children who have been fitted with cochlear implants did not experience significant delay as it relates to phrasing and pitch (Lenden & Flipster Jr., 2006). On the other hand, similar with hearing impaired w/out cochlear implants, resonance, quality and use of stress were clearly an issue for the children in the study ( Lenden & Flipster Jr., 2006). The findings also indicated that prosody and voice characteristics of the conversational speech of children with cochlear implants are not of greater issue than initially predicted. The current study is very encouraging and stresses the benefits of cochlear implantation for children. It is important to point that all the children in the current study received their implants by age 3 and the case can be made with no hesitation for early identification and implantation. As previously mentioned, there are clearly some limitations to the study as the sample size and the sample diversity. Due to these limitations, Lenden & Flipster (2006) could not offer broad conclusions about the age of mastery of the prosody and voice variables. Whereas Lenden and Flipster Jr. (2006) looked at prosody and voice characteristics and Svirsky et al. focused more on the development of language. While most of the studies done on children with cochlear implants focused greatly on perception, it is important to point out that cochlear implants provide critical sensory input important for the development of speech and language production (Svirsky et al., 2004). Also, CI improved children’s anility to improve speech intelligibility and expressive language (Svirsky et al., 2004). In 2004, Svirsky, Teoh, Neurburger agreed that children who undergo cochlear implant at early age may benefit from early exposure to sound before the end of critical/sensitive periods for the development of speech and language (as cited Hurford, 1991; Pickett and Stark, 1987; Ruben, 1996). In the study, Svirsky et al. supported the hypothesis that implantation in the second year of life results in a better speech perception and language development than cochlear implantation done in later. These findings also explain that congenitally deaf children may be able to develop expressive and receptive language skills at a normal pace with some delay, if they only received CIs early enough in life ( Svirsky et al. 2004). As it relates to speech production, speech intelligibility plays a very important role in conversational pattern of children with cochlear implants. In the article, ‘Intelligibility of conversational speech produced by children with cochlear implants’, Flipsen and colleagues discussed the conversational intelligibility of children with cochlear implants. They found that intelligibility scores tend to improve as a function of the length of implant use (e.g., Allen, Nikolopoulos, & Donoghue, 1998; Calmels et al., 2004 etc¦). Flipsen and colleagues (2006), explained that results show that intelligibility of speech tends to be superior in those who receive their implants earlier compared to those who receive it later( as cited in Lohle et al., 1999; Busquet, Roger, Moatti, & Garabedian, 2000; Miyamoto, Iler Kirk, Svirsky, & Sehgal, 1999; Tye-Murray, Spencer, & Wodsworth, 1995). The study done by Filpsen and colleagues (2006) was one of a kind because it apparently is the first to use transcription to quantify conversational intelligibility in this population (with the possible exception of the study by Lohle et al., 1999, in which the analysis method is unclear). Conversational intelligibility for the six participants with cochlear implants was measured in two ways, the utterance-by-utterance approach of original and the overall sample approach of II-AN. The findings are astounding, all six participants developed conversational speech that was more than 65% intelligible. According to the authors, this indicates that cochlear implants may yield much more consistent and better outcomes than have previously been expected for children with severe and profound hearing impairments. Also the authors went on to make the case that it is indeed possible to use transcription to document intelligibility of the conversational speech produced by children fitted with cochlear implants. Prosody in Speech perception As prosody refers to speech perception, there are various areas that have been studied by researchers. In 2007, Clive Frankish in his article, ‘Precategorical acoustic storage and the perception of speech’, established a link between short-term memory and speech perception. Perceptual analysis begins with encoding of acoustic features which are then translated into phonetic and then lexical representations (p.). One important requirement for it to happen is for signal to persist long enough to create patterns that can be mapped onto higher order units at the next level (This type of persisted pattern that Frankish talked about can be perceived as memory. Furthermore Frankish mentioned that those patterns of continued activation will also function as an episodic record in situations where directed retrieval is required. His research suggested that a dialogue should be maintained between researches on speech perception and researches on short term memory (p. 815). Over the years, various researchers have come up with different scenarios that can contribute to speech perception. Frankisha’s research was quite innovative due to the fact that it had established a relationship between short term memory and speech perception. In the case of prosody, speech perception was looked upon on a different angle by Chatterje and colleagues. In 2007, Chatterjee and Peng, made the argument that fundamental frequency contributes to our ability to hear and appreciate musical quality of sounds (p. 143). He and his colleagues went to say that contour in speech provides important information for the processing of prosodic information , e.g. in lexical recognition (p.143). In English, prosody is important because it marks contrasts between various units such as words, sentences and intonation. (as cited in Ladd, 1996; Lehiste, 1970, 1976). For example, F0 will depend on whether or not a sentence is a question or a statement. For e.g The girl is on the school bus vs. The girl is on the school bus? Chatterjee, & Peng, 2007, p.144).It is important to explain the role of F0 as it relates to speech perception. F0 provides primary cues to listener’s speech intonation recognition (Chatterjee, & Peng, 2007, p.144). Chatterjee & Peng (2007) explained that in normal hearing listeners are able to use F0 intensity and duration characteristics of utterances. All of these components serve as a group to identify speech intonation. (as cited in Fry, 1955, 1958; Lehiste,, 1970, 1976). They further explained: Present-day CIs are not designed to specifically deliver F0 information to the listener (p.144).The information provided by F0 is derived from the periodic cues in the time pattern of the acoustic signal. The signals are then transmitted to individual electrodes via the temporal envelope (Chatterjee, & Peng, 2007, p.144). If listeners attempt to get F0 information from temporal envelope cues in spectrally reduced speech , their performance in tasks that require F0 detection can deteriorate (as cited in Green et al., 2002; Fu et al., 2004; Qin and Oxenham, 2005; Sticknney et al., 2004). Chatterjee & Peng (2007) explained enhancing temporal fluctuation of spectrally degraded speech may produce small improvements in F0 processing. It is equally important to say that while CI listeners can process intonation or lexical tone information , it does not necessarily mean that F0 can detect changes (Chatterjee, & Peng, 2007, p.144). It is hard for people with cochlear implants to engage in speaker recognition , gender and tone recognition, all of which involve F0 processing. Although Chatterjee & Peng talked about some of the limitations of cochlear implants as it relates to prosody, Sue-Chen Peng & colleagues explicitly study the acquisition of speech intonation in children with cochlear implants. In 2004, acquisition of rising intonation in pediatric cochlear implant recipients longitudinal study , Peng & colleagues discussed how rising intonation is physiological and requires a great deal of effort (p.337). They go on to explain that intonation is not automatic, but requires purpose and depends on linguistic experience, which requires learning ( Peng et.al, 2004, p.337). They report that as it relates to intonation people with cochlear implants tend to have a harder time with intonation as opposed to hearing impaired people without the device. (Peng et al., 2004, p.338). Some of the challenges that they face are as follows : vowel height, place, and consonant and syllable length. (Peng et al., p.339). Peng & colleagues also report that following implantation they showed some improvements in their production of suprasegmental components. However, this improvement stops after 1 year. This paper has attempted to explain some of the challenges faced by people with cochlear implants as it relates to prosody. The focus has been on two main aspects, which are speech perception and speech . As it relates to speech production , individuals with the device tend to have issues with stress, intonation, loudness and intensity. Confronted with all these challenges, some of the researchers are encouraged over the fact that people with the device seem to acquire language at a faster pace. Researchers are also encouraged in the area of speech perception. Individuals with the device tend to perceive speech 65% of the time. However, as prosody relates t o speech perception, individuals have problems with variation of pitch, F0 loudness, syllable duration and intonation. Throughout the paper, researchers have talked about the limitations of the device. As stated in the introduction, the research is also very limited and the findings are mostly inconclusive. More in-depth research needs to be done, which will give speech pathologists more insights that can be valuable in the aural rehabilitation process. Reference lists. 1. Blamey, P. J. (2001). Relationships among speech perception, production, language, Hearing loss, and age in children with impaired hearing. Journal of Speech, Language, and Hearing Research, 44, 264-285. 2. Bow et al., 2002 C. Bow, P. Blamey, L. Paatsch and J. Sarant, Comparison of methods in speech acquisition research, Clinical Linguistics and Phon etics 16 (2002), pp. 135aˆ“147. 3. Boone, D.R.(1966). The voice and voice therapy. The Volta Review . 68, 686-689. 4. Chatterjee, M., & Peng, S. (2008). Processing F0 with cochlear implants: Modulation frequency discrimination and speech intonation recognition. Hearing Research, 235(1-2) 5. Fletcher et al., 1999 S.G. Fletcher, F. Mahfuzh and H. Hendarmin, Nasalence in the speech of children with normal hearing and children with hearing loss, American Journal of Speech Language Pathology 8 (1999), pp. 241aˆ“248. 6. Flipsen Jr., P., & Parker, R. G. (2008). Phonological patterns in the conversational speech of children with cochlear implants. Journal of Communication Disorders, 41(4), 337-357. 7. Flipsen, J., Peter, & Colvard, L. G. (2005). Intelligibility of conversational speech produced by children with cochlear implants. Journal of Communication Disorders, 39(2), 93-108. 8. Frankish, F., (2007). Precategorical acoustic storage and the perception of speech. Journal of Memory and Language, 58, 815-836. 9. Lenden, J. M., & Flipsen Jr., P. (2007). Prosody and voice characteristics of children with cochlear implants. Journal of Communication Disorders, 40(1), 66-81. 10. A Peng, S., Tomblin, J. B., Spencer, L. J., & Hurtig, R. R. (2004). Acquisition of risi ng intonation in pediatric cochlear implant recipientsaˆ”a longitudinal study. International Congress, 336-339. 11. Svirsky,M.A., Teoh, S.W., & Neuburger, H. (2004). Development of language and speech perception in congenitally, profoundly deaf children as a function of age at cochlear implantation, Audiology & Neurology, 9(4), 225-232. 13. Subtelny et al., 1980 J. Subtelny, R. Whitehead and N. Orlando, Description and evaluation of an instructional program to improve speech and voice diagnosis of the hearing impaired, The Volta Review 82 (1980), pp. 85aˆ“95. 14. A Paatsch, L.E., Blamey, P.J., Sarant, J.Z., Martin, L.F.A., & Bow, C.P.(2004). Separating contributions of hearing, lexical, knowledge, and speech production to speech perception scores in children with hearing impairments, Journal of Speech, Language, and Hearing Research, 47, 738-750. 15. Shriberg et al., 1990 L.D. Shriberg, J. Kwiatkowski and C. Rasmussen, Prosody-Voice Screening Profile(PVSP) Communication Skill Builders, Tucson, AZ (1990). 16. Shriberg et al., 1997 L.D. Shriberg, D.M. Aram and J. Kwiatkowski, Developmental apraxia of speech II: Toward a diagnostic marker, Journal of Speech, Language, and Hearing Research 40 (1997), pp. 286aˆ“312. 17. Tobey,E.A.,A Angelette, C. Murchison, J. Nicosia, S. SpragueA & . Staller, S.J.(1991).Speech production performance in children with multichannel cochlear implants, American Journal of Otology 12 (1991), pp. 165aˆ“173 Read More