Verbal learning and memory in prelingually deaf children with cochlear implants

Abstract

Objective: Deaf children with cochlear implants (CIs) show poorer verbal working memory compared to normal-hearing (NH) peers, but little is known about their verbal learning and memory (VLM) processes involving multi-trial free recall.

Design: Children with CIs were compared to NH peers using the California Verbal Learning Test for Children (CVLT-C).

Study sample: Participants were 21 deaf (before age 6?months) children (6–16?years old) implanted prior to age 3?years, and 21 age-IQ matched NH peers.

Results: Results revealed no differences between groups in number of words recalled. However, CI users showed a pattern of increasing use of serial clustering strategies across learning trials, whereas NH peers decreased their use of serial clustering strategies. In the CI sample (but not in the NH sample), verbal working memory test scores were related to resistance to the build-up of proactive interference, and sentence recognition was associated with performance on the first exposure to the word list and to the use of recency recall strategies.

Conclusions: Children with CIs showed robust evidence of VLM comparable to NH peers. However, their VLM processing (especially recency and proactive interference) was related to speech perception outcomes and verbal WM in different ways from NH peers.     

Speech perception performance in prelingually deaf children with cochlear implants

The goals of this study were to report on mean values of speech perception performance in prelingually deaf children implanted with a Combi 40/40 + cochlear implant. A total of 31 patients were included in the study. The time span ranged over 3 years, during which time the Evaluation of Auditory Responses to Speech (EARS) test battery was used with the children. The EARS battery contains four measures of closed-set speech perception and three open-set tests. The mean test results exhibited steady improvement on all parts of the EARS test battery, even up to 3 years post-implantation. The preoperative scores for the Listening Progress Profile (LiP) were 4%, rising to 93% at 36 months post-implantation. Results for the open-set testing measures were most encouraging, with some children reaching fairly high levels of speech perception, receiving scores as high as 100%, by the 36-month evaluation. The congenitally and prelingually deaf children in our study showed continuous improvement in both closed and open set speech perception following cochlear implantation, although variability in individual performance among the children was noted.     

Changes of the late acoustically evoked potentials in postlingually deaf patients with cochlear implants

BACKGROUND: The speech recognition performances in postlingually deaf patients, which had a long duration of deafness, seem to be poorer than in patients with a short duration of deafness. The reason could be a functional reorganization in the auditory cortex. A long time of auditory deprivation may decrease neuronal activity in the auditory related cortices. As the late acoustically evoked potentials are generated in this region, we compared the speech recognition performances and also the late acoustically evoked potentials with the individual duration of deafness in a series of postlingually deaf patients. METHODS: In 9 patients (cochlear implant (CI), MED EL) with postlingual deafness the late acoustically evoked potentials and the HSM-set-test on the quiet were measured. Additionally 1 patient with prelingual deafness was examined. The CI-operation was done, when he was 14 years old. The relations between the late acoustically evoked potentials and the speech recognition performances in dependence of the duration of deafness were examined. RESULTS: Typical late acoustically evoked potentials could be measured in 3 patients only. The speech recognition in these patients was very good. The longest time of deafness in these patients was 6 years. In 6 patients the minimum duration of deafness was 12 years. Here were measured the N1-potentials only, the P2- and the N2-potentials were absent. In these patients the scores of the HSM-set-test were lower than in the others. In the 15-years old patient with prelingual deafness the speech recognition was absent. The late acoustically evoked potentials of this patient showed an atypical form. CONCLUSIONS: The results of this study showed a correlation between the duration of deafness, the forms of the late acoustically evoked potentials and the speech perception. The duration of deafness preceding CI-implantation should be very small in deaf children and in postlingually deaf patients.     

Objective methods in postlingually and prelingually deafened adults for programming cochlear implants: ESR and NRT

This study compared responses of prelingually and postlingually deafened adult Nucleus 24 cochlear implant users on two objective measures employed to predict programming levels: neural response telemetry (NRT) and electrically evoked stapedial reflexes (eSR). Thirty experienced postlingually and prelingually deafened adult implant users underwent standard behavioural judgements of maximum comfortable loudness levels (C levels) and thresholds (Ts) followed by eSR and NRT measurements. Two different programs were created based on both the subjective judgement and the objective estimates of C levels (eSR thresholds) and these were compared. Relationships between the subjective and the objective measures were statistically analysed. Maximum stimulation levels estimated by both eSR and NRT were highly correlated with C levels. Variability of NRT results was higher than for eSR results. Mean NRT thresholds for postlingually deafened patients were higher than for prelingually deafened patients. A number of prelingually deafened users could distinguish no difference between programs; however, the majority of postlingually deafened users were sensitive to the difference and many reported preference for the program with eSR-estimated C levels. Neural response telemetry thresholds and eSRTs obtained in Nucleus 24 patients are highly correlated with C levels and Ts. Results suggest that estimation of C levels and Ts using NRT or eSR requires different correction factors for prelingually versus postlingually deafened adult subjects.     

Development of audiovisual comprehension skills in prelingually deaf children with cochlear implants

OBJECTIVE: The present study investigated the development of audiovisual comprehension skills in prelingually deaf children who received cochlear implants. DESIGN: We analyzed results obtained with the Common Phrases (Robbins et al., 1995) test of sentence comprehension from 80 prelingually deaf children with cochlear implants who were enrolled in a longitudinal study, from pre-implantation to 5 years after implantation. RESULTS: The results revealed that prelingually deaf children with cochlear implants performed better under audiovisual (AV) presentation compared with auditory-alone (A-alone) or visual-alone (V-alone) conditions. AV sentence comprehension skills were found to be strongly correlated with several clinical outcome measures of speech perception, speech intelligibility, and language. Finally, pre-implantation V-alone performance on the Common Phrases test was strongly correlated with 3-year postimplantation performance on clinical outcome measures of speech perception, speech intelligibility, and language skills. CONCLUSIONS: The results suggest that lipreading skills and AV speech perception reflect a common source of variance associated with the development of phonological processing skills that is shared among a wide range of speech and language outcome measures.     

Perception and production of mandarin tones in prelingually deaf children with cochlear implants

OBJECTIVE: Mandarin is a lexical tone language in which four tones are crucial for determining lexical meanings. Acquisition of such a tone system may be challenging to prelingually deaf children with cochlear implants because, as recent studies have shown, cochlear implant devices are ineffective in encoding voice pitch information required for tone recognition. This study aimed to investigate Mandarin tone production and perception skills of children with cochlear implants. DESIGN: Thirty prelingually deaf children with cochlear implants, ages 6;0 (yr;mo) to 12;6, participated. These children received their implants at an average age of 5;8, with a range from 2;3 to 10;3. The average length of their cochlear implant experience was 3;7, with a range from 1;7 to 6;5. Tasks of tone production and tone identification involved a pictorial protocol of 48 words containing the targeted tones in either monosyllabic or disyllabic forms. RESULTS: The average scores for tone production was 53.09% (SD = 15.42), and for tone identification was 72.88% (SD = 19.68; chance level = 50%). Significant differences were found in the percentages across the production or identification of tone types or tone pairs. The children with exceptional performance in tone production tended to also perform well in tone identification. The children's performance levels in tone identification and production were also discussed in relation to the factors of age at implantation and length of cochlear implant experience. CONCLUSIONS: The present results suggest that the majority of prelingually deaf children with cochlear implants did not master Mandarin tone production. However, a small group of participants demonstrated nearly perfect skills of Mandarin tone production in addition to tone perception. Thus, it is necessary to consider factors other than the device's limitations to explain these high levels of performance in the perception and production of Mandarin lexical tones.     

Quality of life in postlingually deaf patients following cochlear implantation

Most cochlear implant studies are focused on improvement of speech perception associated with implantation. The goal of this study was to assess the impact of cochlear implantation on quality of life changes in Spanish users. Thirty postlingually deaf patients fitted with a cochlear implant completed the Glasgow Benefit Inventory, a questionnaire dealing with communication abilities, and an open-ended questionnaire. The Glasgow Benefit Inventory revealed a positive effect in 93% of patients. The use of a cochlear implant significantly enhanced discrimination ability, telephone use and self-confidence. A high degree of satisfaction was achieved in all situations except with background noise. Ninety-six percent of patients would recommend the operation to a friend. A dramatic improvement in quality of life following cochlear implantation is revealed by a great majority of patients. The results cannot only be explained by enhancements to auditory perception.     

Development of visual attention skills in prelingually deaf children who use cochlear implants

OBJECTIVE: To determine the effects of length of cochlear implant use and other demographic factors on the development of sustained visual attention in prelingually deaf children and to examine the relations between performance on a test of sustained visual attention and audiological outcome measures in this population. DESIGN: A retrospective analysis of data collected before cochlear implantation and over several years after implantation. Two groups of prelingually deaf children, one >6 years old (N = 41) and one <6 years old (N = 47) at testing, were given an age-appropriate Continuous Performance Task (CPT). In both groups, children monitored visually presented numbers for several minutes and responded whenever a designated number appeared. Hit rate, false alarm rate, and signal detection parameters were dependent measures of sustained visual attention. We tested for effects of a number of patient variables on CPT performance. Multiple regression analyses were conducted to determine if CPT scores were related to performance on several audiological outcome measures. RESULTS: In both groups of children, mean CPT performance was low compared with published norms for normal-hearing children, and performance improved as a function of length of cochlear implant use and chronological age. The improvement in performance was manifested as an increase in hit rate and perceptual sensitivity over time. In the younger age group, a greater number of active electrodes predicted better CPT performance. Results from regression analyses indicated a relationship between CPT response criterion and receptive language in the younger age group. However, we failed to uncover any other relations between CPT performance and speech and language outcome measures. CONCLUSIONS: Our findings suggest that cochlear implantation in prelingually deaf children leads to improved performance on a test of sustained visual processing of numbers over 2 or more years of cochlear implant use. In preschool-age children who use cochlear implants, individuals who are more conservative responders on the CPT show higher receptive language scores than do individuals with more impulsive response patterns. Theoretical accounts of these findings are discussed, including cross-modal reorganization of visual attention and enhanced phonological encoding of visually presented numbers.     

Performance over time of congenitally deaf and postlingually deafened children using a multichannel cochlear implant.

The speech perception performance of 10 congenitally deaf and 3 postlingually deafened children who received the Cochlear Corporation multichannel cochlear implant was examined and compared. The children were tested preimplant and at 6-month intervals up to 2 years using the Monosyllable-Trochee-Spondee test (MTS), the Word Intelligibility by Picture Identification test (WIPI), and Phonetically Balanced Kindergarten (PB-K) or Northwestern University List 6 (NU-6) word lists. The postlingually deafened children exhibited significantly improved performance on open- and closed-set tests of word recognition after 6 months of implant use, a pattern similar to that of postlingually deafened adult implant users. In contrast, the congenitally deaf children did not exhibit measurably improved performance on speech perception tests until after 12 months or more of implant use. With as much as 18-24 months of use, however, some congenitally deaf children demonstrated limited open-set word recognition.     

Long-term language levels and reading skills in mandarin-speaking prelingually deaf children with cochlear implants

The aim of this study was to document receptive and expressive language levels and reading skills achieved by Mandarin-speaking children who had received cochlear implants (CIs) and used them for 4.75-7.42 years. The effects of possible associated factors were also analyzed. Standardized Mandarin language and reading tests were administered to 39 prelingually deaf children with Nucleus 24 devices. The Mandarin Chinese version of the Peabody Picture Vocabulary Test was used to assess their receptive vocabulary knowledge and the Revised Primary School Language Assessment Test for their receptive and expressive language skills. The Graded Chinese Character Recognition Test was used to test their written word recognition ability and the Reading Comprehension Test for their reading comprehension ability. Raw scores from both language and reading measurements were compared to normative data of nor- mal-hearing children to obtain standard scores. The results showed that the mean standard score for receptive vocabulary measurement and the mean T scores for the receptive language, expressive language and total language measurement were all in the low-average range in comparison to the normative sample. In contrast, the mean T scores for word and text reading comprehension were almost the same as for their age-matched hearing counterparts. Among all children with CIs, 75.7% scored within or above the normal range of their age-matched hearing peers on receptive vocabulary measurement. For total language, Chinese word recognition and reading scores, 71.8, 77 and 82% of children with CIs were age appropriate, respectively. A strong correlation was found between language and reading skills. Age at implantation and sentence perception scores account for 37% of variance for total language outcome. Sentence perception scores and preimplantation residual hearing were revealed to be associated with the outcome of reading comprehension. We concluded that by using standard tests, the language development and reading skill of Mandarin-speaking children who use CIs from a young age appear to fall within the normal range of their hearing age mates, at least after 4.8-7.4 years of experience. However, to fully evaluate the fine linguistic skills of these subjects, a more detailed study and longer follow-up period are needed.     

Behavioral assessment of prelingually deaf children before cochlear implantation

Objectives/Hypothesis: To determine whether scores from a behavioral assessment of prelingually deafened children who present for cochlear implant surgery are predictive of audiological outcomes Study Design: Retrospective review of longitudinal data collected from 42 children with prelingual hearing loss who presented for a cochlear implant before age 5 years. Methods: The Vineland Adaptive Behavioral Scales (VABS) was administered during the preimplant workup. Standardized scores reflect daily living skills, socialization, and motor development compared with a normative sample. Regression analyses were conducted to determine whether any subject variables were related to VABS scores. Mixed‐model analyses were computed to determine whether preimplant VABS scores were predictive of longitudinal spoken‐language data obtained after cochlear implant surgery. Results: Motor scores tended to be higher than nonmotor scores. Nonmotor scores were significantly lower than the normative mean and decreased with testing age. Children with acquired deafness demonstrated lower motor scores than children with congenital causes. Children with higher motor scores demonstrated significantly higher performance on language, vocabulary, and word recognition tests than children with lower motor scores. Nonmotor domains were not as robustly related to spoken‐language measures, although similar trends were observed Conclusion: Profound deafness and language delay may confound the assessment of daily living skills and socialization in the population studied. Motor development appears to proceed normally in prelingually deafened children and is a preimplant predictor of spoken‐language outcome in young infants and children with cochlear implants, a finding consistent with the large body of work establishing links between perceptual‐motor and language development.     

成人语后聋患者人工耳蜗植入适应证探讨

目的:探讨语后聋患者人工耳蜗植入的手术适应证及人工耳蜗在语后聋患者言语康复和社会活动中的作用.方法:5例语后聋患者手术年龄为19～58岁(中位年龄26岁).5例患者均手术植入Cochlear 24R人工耳蜗.术后4周开机,随访1年,调查采用听觉行为分级标准(CAP)和言语识别率分级标准(SIR),由1名研究者完成随访,随访涉及听力水平、言语交流能力2个方面的内容.结果:5例患者术后1年0.5、1.0、2.0、4.0 kHz助听听阈均在25～45 dB;CAP平均3.4,SIR平均2.4.2例患者言语分辨能力及情感交流能力无明显提高,其余3例患者交流能力均有不同程度提高.结论:对于不同原因所致的语后聋患者,正确选择手术适应证,均能使之从人工耳蜗植入术中不同程度获益,提高其独立生活能力及自信心.     

Verbal self-monitoring in deaf subjects using cochlear implants

Cortical activation during vocalization was studied in an attempt to elucidate verbal self-monitoring mechanisms in cochlear implant users. Six post-lingually deafened subjects using cochlear implants were included in this study. Significant activation was observed in the bilateral temporal cortices during reading sentences aloud, which was not found in normal subjects in our previous study. The activation patterns in the temporal cortex were similar for reading aloud and for listening to the examiner's speech, and the activation foci in the middle temporal gyri for the two tasks were almost identical. Cochlear implant users may monitor their own speech during speech production, and their verbal self-monitoring mechanisms are thought to depend on similar mechanisms that are used to monitor externally generated speech.     

The case for earlier cochlear implantation in postlingually deaf adults

Abstract

Objective: This paper aimed to estimate the difference in speech perception outcomes that may occur due to timing of cochlear implantation in relation to the progression of hearing loss. Design: Data from a large population-based sample of adults with acquired hearing loss using cochlear implants (CIs) was used to estimate the effects of duration of hearing loss, age, and pre-implant auditory skills on outcomes for a hypothetical standard patient. Study sample: A total of 310 adults with acquired severe/profound bilateral hearing loss who received a CI in Melbourne, Australia between 1994 and 2006 provided the speech perception data and demographic information to derive regression equations for estimating CI outcomes. Results: For a hypothetical CI candidate with progressive sensorineural hearing loss, the estimates of speech perception scores following cochlear implantation are significantly better if implantation occurs relatively soon after onset of severe hearing loss and before the loss of all functional auditory skills. Conclusions: Improved CI outcomes and quality of life benefit may be achieved for adults with progressive severe hearing loss if they are implanted earlier in the progression of the pathology.     

Neuroelectrical imaging investigation of cortical activity during listening to music in prelingually deaf children with cochlear implants

Objective

To date, no objective measure of the pleasantness of music perception by children with cochlear implants has been reported. The EEG alpha asymmetries of pre-frontal cortex activation are known to relate to emotional/affective engagement in a perceived stimulus. More specifically, according to the “withdrawal/approach” model, an unbalanced de-synchronization of the alpha activity in the left prefrontal cortex has been associated with a positive affective state/approach toward a stimulus, and an unbalanced de-synchronization of the same activity in the right prefrontal cortex with a negative affective state/withdrawal from a stimulus. In the present study, High-Resolution EEG with Source Reconstruction was used to compare the music-induced alpha asymmetries of the prefrontal cortex in a group of prelingually deaf implanted children and in a control group of normal-hearing children.

Methods

Six normal-hearing and six age-matched deaf children using a unilateral cochlear implants underwent High-Resolution EEG recordings as they were listening to a musical cartoon. Musical stimuli were delivered in three versions: Normal, Distort (reverse audio flow) and Mute. The EEG alpha rhythm asymmetry was analyzed: Power Spectral Density was calculated for each Region of Interest, together with a right-left imbalance index. A map of cortical activation was then reconstructed on a realistic cortical model.

Results

Asymmetries of EEG alpha rhythm in the prefrontal cortices were observed in both groups. In the normal-hearing children, the asymmetries were consistent with the withdrawal/approach model, whereas in cochlear implant users they were not. Moreover, in implanted children a different pattern of alpha asymmetries in extrafrontal cortical areas was noticed as compared to normal-hearing subjects.

Conclusions

The peculiar pattern of alpha asymmetries in implanted children's prefrontal cortex in response to musical stimuli suggests an inability by these subjects to discriminate normal from dissonant music and to appreciate the pleasantness of normal music. High-Resolution EEG may prove to be a promising tool for objectively measuring prefrontal cortex alpha asymmetries in child cochlear implant users.     

语前聋儿童人工耳蜗植入效果的评估

目的探索语前聋儿童人工耳蜗植入效果的评估方法.方法受试者为18名接受人工耳蜗植入的语前聋儿童,耳蜗植入时平均年龄6岁.按人工耳蜗使用时间长短分为四个阶段进行评估:第一阶段18名患儿,使用人工耳蜗1～12个月;第二阶段12名,使用人工耳蜗13～24个月;第三阶段8名,使用人工耳蜗25～36个月;第四阶段6名,使用人工耳蜗在36个月以上.描述性分析,以问卷的形式了解儿童在人工耳蜗植入后声音接受、言语表达及行为等方面的变化;言语测试,进行言语识别能力和发声能力测试.结果第一阶段患儿,能够感知和辨别来自家庭和环境中的声音;第二阶段患儿,封闭项词识别率是51%,开放项词识别开始启动;第三阶段患儿,封闭项词识别率达到72%,开放项词识别率是40%,能正确发出的单词数是42%;第四阶段患儿,封闭项词识别率和开放项词识别率分别达到84%和53%,能正确发出的单词数达62%,部分患儿已有自发的口语表达.结论人工耳蜗植入对语前聋患儿的言语发育有帮助,患儿的言语能力随着人工耳蜗使用时间的推移不断进步.     

Results of speech perception and speech production training for three prelingually deaf patients using a multiple-electrode cochlear implant.

Five studies were conducted to measure changes in the perception and production of selected speech targets, with training, in three prelingually deaf patients. The two adults and one adolescent were implanted with the Cochlear (Nucleus) multiple-electrode prosthesis. The studies were perception and production of nasal consonants; perception of syllable-final consonants; perception and production of alveolar consonants; auditory-visual perception of alveolar consonants; and perception and production of vowels. Perceptual data were collected in the audition (implant)-alone condition, except for the auditory-visual perception of alveolar consonants where the audition-alone, vision-alone, and auditory-visual conditions were used. Speech perception data in the audition-alone condition were also collected from four postlingually deaf adult implant patients, without training, to indicate differences between the two classes of patients. The three prelingually deaf patients generally showed some improvements in speech production. In perception, improvements were recorded only for individual patients in some studies. The performance of the adolescent was better than that of the two adults in all cases. The perceptual performance of the postlingually deaf patients was superior to that of the prelingually deaf patients in all cases.     

Variables affecting speech perception in postlingually deaf adults following cochlear implantation

OBJECTIVE: To evaluate the time span over which there is greatest improvement in postlingually deaf adults undergoing cochlear implantation. Additionally, to quantify potential patient and device factors that may predict the postoperative results. MATERIAL AND METHODS: A longitudinal study was conducted. Numbers, monosyllables and sentence test results were collected for 66 cochlear implant subjects [Combi 40/40 +, n = 60; Clarion HF2, n = 2; Nucleus 24m/k, n = 4] at regular intervals for up to 6 years following cochlear implantation. RESULTS: All patients showed a steady improvement over time on all tests. Progress during the first 12 months was statistically significant, with further improvements being recorded after the 12-month testing period. The duration of deafness and the number of electrodes (8 for the Combi 40, 12 for the Combi 40 + ) appeared to be weakly correlated with postoperative performance. Re-implantation after device failure had no negative effect on speech reception. Subjects who were "upgraded" from an analogue to a digital cochlear implant improved their test results almost twofold. CONCLUSION: All the patients in our study gained substantial benefit from their cochlear implants. It is encouraging to note that the factors examined were not deemed to be relevant predictors of performance. Even long-term deaf subjects and re-implantees are able to achieve an excellent level of speech perception.     

Preliminary results for the cochlear corporation multielectrode intracochlear implant in six prelingually deaf patients

The preliminary results from this study indicate that some prelingually deaf patients may get worthwhile help from a multiple-electrode cochlear implant that uses a formant-based speech processing strategy. It is encouraging that these improvements can occur in young adults and teenagers. The results for two children are also encouraging. A 10-year-old child obtained significant improvement on some speech perception tests. It was easy to set thresholds and comfortable listening levels on a 5-year-old child, and he is now a regular user of the device. There are, however, considerable variations in performance among the prelingual patients, which may be related to the following factors: whether they have had some hearing after birth, the method of education used, the motivation of the patient, and age at implantation.     

语后聋成人人工耳蜗植入后言语感知能力的测评

目的通过对植入人工耳蜗的语后聋成人听力言语感知能力的测评,探讨人工耳蜗对语后聋成人言语康复的作用.方法受试者为14名语后聋成人患者,男性9例,女性5例;耳蜗植入年龄22岁～67岁,平均46岁;耳聋时间6年-42年,平均16年.在人工耳蜗植入6个月、12个月及24个月时,进行开放性单词和短句言语感知测试.分别在三种模式下进行:只听模式(开放人工耳蜗)、听觉加视觉模式(开放人工耳蜗加唇读)及视觉模式(关闭人工耳蜗只用唇读).结果在听觉模式及听觉加视觉模式下,患者对单词和句子的正确感知随人工耳蜗使用时间而不断改善.术后6个月,听觉模式下的开放性单词和短句的正确感知率分别是38%和54%;听觉加视觉模式下的开放性单词和短句的正确感知率分别是70%和76%.术后24个月,听觉模式下的开放性单词和短句的正确感知率分别是65%和72%;听觉加视觉模式下的开放性单词和短句的正确感知率分别是84%和88%.结论人工耳蜗植入能显著改善语后聋成人的言语感知能力,并随着人工耳蜗使用时间的增加,言语感知能力逐渐得到提高.