Effects of frontal-executive dysfunction on self-perceived hearing handicap in the elderly with mild cognitive impairment.

It is increasingly agreed upon that cognitive and audiological factors are associated with self-perceived hearing handicap in old adults. This study aimed to compare self-perceived hearing handicap among mild cognitive impairment (MCI) subgroups and a cognitively normal elderly (CNE) group and determine which factors (i.e., demographic, audiometric, or neuropsychological factors) are correlated with self-perceived hearing handicap in each group. A total of 46 MCI patients and 39 hearing threshold-matched CNE subjects participated in this study, and their age ranged from 55 to 80 years. The MCI patients were reclassified into two groups: 16 with frontal-executive dysfunction (FED) and 30 without FED. All subjects underwent audiometric, neuropsychological, and self-perceived hearing handicap assessments. The Korean version of the Hearing Handicap Inventory for the Elderly (K-HHIE) was administered to obtain the hearing handicap scores for each subject. After controlling for age, years of education, and depression levels, we found no significant differences in the K-HHIE scores between the MCI and the CNE groups. However, after we classified the MCI patients into the MCI with FED and MCI without FED groups, the MCI with FED group scored significantly higher than did both the MCI without FED and the CNE groups. In addition, after controlling for depression levels, significant partial correlations of hearing handicap scores with frontal-executive function scores and speech-in-noise perception performance were found in the MCI groups. In the CNE group, the hearing handicap scores were related to peripheral hearing sensitivity and years of education. In summary, MCI patients with FED are more likely to experience everyday hearing handicap than those without FED and cognitively normal old adults. Although educational level and peripheral hearing function are related to self-perceived hearing handicap in cognitively normal old adults, speech-in-noise perception and frontal-executive function are mainly associated with hearing handicap in patients with MCI.

Association between Frontal-Executive Dysfunction and Speech-in-Noise Perception Deficits in Mild Cognitive Impairment.

BACKGROUND AND PURPOSE: Speech-in-noise perception deficits have been demonstrated in patients with mild cognitive impairment (MCI). However, it remains unclear whether the impairment of speech perception varies between MCI subtypes. The purpose of this study was twofold: 1) to compare speech perception performance among MCI subgroups, and 2) to identify the cognitive domains specifically related to speech-in-noise perception. METHODS: We studied 46 patients with MCI and 39 hearing-threshold-matched cognitively normal elderly (CNE) subjects. Two different patient classifications were used: 1) patients with amnestic mild cognitive impairment (aMCI) (n=21) or nonamnestic mild cognitive impairment (naMCI) (n=25), and 2) patients with frontal-executive dysfunction (FED) (n=16) or without FED (n=30). All of the subjects underwent audiometric, neuropsychological, and speech perception assessments. Speech-in-noise perception was measured using sentence recognition tests in the presence of two types of background noise at four levels. RESULTS: First, as the level of background noise increased, the MCI with FED group scored lower than both the MCI without FED and CNE groups under both types of noise. Second, both the naMCI and aMCI groups scored lower than the CNE group, but there were no differences between the naMCI and aMCI groups in sentence recognition under any noise conditions. Third, significant correlations were found between sentence recognition and executive function scores both in the MCI groups and in the CNE group. CONCLUSIONS: Our findings suggest that frontal-executive function is strongly related to speech-in-noise perception and that MCI patients with FED have greater deficits in speech-in-noise perception compared to other subgroups of MCI.

P1 cortical auditory evoked potential in children with unilateral or bilateral cochlear implants; implication for the timing of second cochlear implantation.

OBJECTIVE: To examine maturation of the central auditory pathway, using P1 cortical auditory evoked potential (CAEP), in children who had received unilateral or bilateral cochlear implantation (CI). STUDY DESIGN: Prospective study. SETTING: Tertiary referral hospital. METHODS: Twenty children who had received CI due to congenital, or prelingual, deafness participated in the study. Participants had received the 1st implant at a mean age of 3.4 ± 0.7 years; 16 had also received a 2nd CI for the contralateral ear, at a mean age of 11.1 ± 2.1 years. P1 CAEP was recorded while using the 1st implant and, for those who received contralateral CI, within 2 weeks of switching on the 2nd implant. Relations between P1 latency and duration with the 1st implant, and between age at 1st CI and P1 latency, were investigated. Relations between P1 latency with the 1st and 2nd implants, and between the interstage interval and difference between P1 latencies with the 1st and 2nd implants, were also examined. RESULTS: P1 CAEP with the 1st implant was present in 16 of the 20 children. Mean P1 latency was shorter in the early CI group compared with the late CI group, but this difference was not statistically significant (p = 0.154). There was a significant negative correlation between the duration with the 1st implant and P1 latency (r = - 0.783, p < 0.001). Among the 16 children with sequential bilateral CI, P1 CAEP with the 2nd implant was present in 10. There was a significant negative correlation between the duration with the 1st implant before receiving the 2nd implant and P1 latency with the 2nd implant (r = - 0.710, p = 0.021); there was also a significant positive correlation between P1 latency with the 1st and 2nd implants (r = 0.722, p = 0.018). There was not a significant correlation between interstage interval and the difference between the two P1 latencies (r = - 0.430, p = 0.248). CONCLUSION: Longer cochlear implant use is associated with shorter P1 latency. Unilateral hearing with the 1st implant may positively affect P1 latency with the 2nd CI ear. These findings imply that increased auditory experience may influence central auditory pathway maturation and that the degree of central auditory pathway maturation before the 2nd CI, rather than the timing when the surgery is received, may influence 2nd CI outcome in children with sequential bilateral cochlear implants.

A Case of Auditory Neuropathy Caused by Pontine Hemorrhage in an Adult.

A pontine hemorrhage can evoke several neurological symptoms because the pons contains various nuclei and nerve fibers. Hearing loss can develop as a result of a pontine hemorrhage because there is an auditory conduction pathway in the cochlear nucleus of the pons. However, very few cases of hearing loss caused by pontine lesions have been reported, and there have been no reports of auditory neuropathy that developed following a pontine hemorrhage. Recently we had a patient who experienced a nontraumatic pontine hemorrhage who was diagnosed with auditory neuropathy. The 34-year-old male patient was admitted to the emergency department with sudden alteration of mental status. His brain computed tomographic imaging revealed a hemorrhage in the central pons. He complained of hearing difficulties after his mental status recovered through conservative treatment, but a pure-tone audiogram showed very mild hearing loss in both ears. Further hearing tests using otoacoustic emissions, which showed normal responses, and auditory brainstem responses, which showed no waveforms at maximum stimulus intensity, revealed that his hearing difficulties were caused by auditory neuropathy. This case implies that the threshold of sound detection can be preserved in patients with pontine hemorrhage who complain of hearing difficulties. Auditory neuropathy should be considered as a possible cause of hearing difficulties in these patients and appropriate hearing tests should be performed.

Effects of Noise Level and Cognitive Function on Speech Perception in Normal Elderly and Elderly with Amnestic Mild Cognitive Impairment.

OBJECTIVE AND BACKGROUND: Along with auditory function, cognitive function contributes to speech perception in the presence of background noise. Older adults with cognitive impairment might, therefore, have more difficulty perceiving speech-in-noise than their peers who have normal cognitive function. We compared the effects of noise level and cognitive function on speech perception in patients with amnestic mild cognitive impairment (aMCI), cognitively normal older adults, and cognitively normal younger adults. METHODS: We studied 14 patients with aMCI and 14 age-, education-, and hearing threshold-matched cognitively intact older adults as experimental groups, and 14 younger adults as a control group. We assessed speech perception with monosyllabic word and sentence recognition tests at four noise levels: quiet condition and signal-to-noise ratio +5 dB, 0 dB, and -5 dB. We also evaluated the aMCI group with a neuropsychological assessment. RESULTS: Controlling for hearing thresholds, we found that the aMCI group scored significantly lower than both the older adults and the younger adults only when the noise level was high (signal-to-noise ratio -5 dB). At signal-to-noise ratio -5 dB, both older groups had significantly lower scores than the younger adults on the sentence recognition test. The aMCI group's sentence recognition performance was related to their executive function scores. CONCLUSIONS: Our findings suggest that patients with aMCI have more problems communicating in noisy situations in daily life than do their cognitively healthy peers and that older listeners with more difficulties understanding speech in noise should be considered for testing of neuropsychological function as well as hearing.

Delayed-onset hearing loss in pediatric candidates for cochlear implantation.

The objective of this study was to evaluate the clinical significance of delayed-onset hearing loss in children. Seventy-three children who underwent cochlear implantation (CI) were included. They were divided into a congenital hearing loss group (n = 50) and a delayed-onset hearing loss group (n = 23). The age at diagnosis of hearing loss, age at the beginning of auditory habilitation, the age at CI, and the postimplant speech perception abilities were compared between the two groups. Children in the congenital hearing loss group were confirmed to have hearing loss at a mean age of 0.3 years, and those in the delayed-onset hearing loss group were diagnosed with hearing loss at a mean age of 2.0 years. Auditory habilitation began at a mean age of 0.4 and 2.0 years, and CI was performed at a mean age of 1.4 and 2.6 years, respectively. Children in the congenital hearing loss group had better scores on speech perception tests than those in the delayed-onset hearing loss group, but the differences were not significant. About half of the children with delayed-onset hearing loss (57 %) had risk factors associated with delayed-onset hearing loss. A high prevalence of delayed-onset hearing loss was noted in the group of children who underwent CI. Risk factors for hearing loss were not found in 43 % of children with delayed-onset hearing loss. Universal screening for delayed-onset hearing loss needs to be performed during early childhood.

Criteria for Selecting an Optimal Device for the Contralateral Ear of Children with a Unilateral Cochlear Implant.

OBJECTIVE: To identify clinical criteria for selecting the aiding device for the contralateral ear of children with a unilateral cochlear implant (CI). METHODS: Sixty-five children, including 36 bilateral CI users and 29 bimodal users, participated in the study. A speech perception test (monosyllabic word test) in noise was administered. The target speech (65 dB sound pressure level) was presented from the front loudspeaker, and noise (10 dB signal-to-noise ratio) was presented from 3 directions: from in front of the child and 90° to the child's right and left sides. The test was performed using the first CI alone and under bilateral CI or bimodal conditions. The bilateral benefits to speech perception in noise were compared between bilateral CI users and bimodal users. RESULTS: Significant benefits in speech perception in noise were evident in bilateral CI users in all 3 noise conditions. In bimodal users, the hearing threshold at low frequencies of ≤1 kHz in the nonimplanted ear affected the bilateral benefit. Bimodal users with a low-frequency hearing threshold ≤90 dB hearing level (HL) showed a significant bilateral benefit in various noise conditions. By contrast, bimodal users with a low-frequency hearing threshold >90 dB HL showed no significant bilateral benefits in all 3 noise conditions. CONCLUSIONS: Bilateral CI and bimodal listening provide better speech perception in noise than unilateral CI alone in children. The contralateral CI is better than bimodal listening for children with a low-frequency hearing threshold >90 dB HL. A hearing threshold at low frequencies of ≤1 kHz may be a good criterion for deciding on the type of device for the contralateral ear of children with a unilateral CI.

A new classification of cochleovestibular malformations and implications for predicting speech perception ability after cochlear implantation.

OBJECTIVES: The aims of this study were to introduce a new classification of cochleovestibular malformation (CVM) and to investigate how well this classification can predict speech perception ability after cochlear implantation in children with CVM. METHODS: Fifty-nine children with CVM who had used a cochlear implant for more than 3 years were included. CVM was classified into 4 subtypes based on the morphology of the cochlea and the modiolus on temporal bone computed tomography (TBCT): normal cochlea and normal modiolus (type A, n = 16), malformed cochlea and partial modiolus (type B, n = 31), malformed cochlea and no modiolus (type C, n = 6), and no cochlea and no modiolus (type D, n = 6). Speech perception test scores were compared between the subtypes of CVM using analysis of covariance with post hoc Bonferroni test. Univariate and multivariate regression analyses were used to identify the significant predictors of the speech perception test scores. RESULTS: The speech perception test scores after implantation were significantly better in children with CVM type A or type B than in children with CVM type C or type D. The test scores did not differ significantly between the implanted children with CVM type A or type B and those without CVM. In univariate regression analysis, the type of CVM was a significant predictor of the speech perception test scores in implanted children with CVM. Multivariate regression analysis revealed that the age at cochlear implantation, cochlear nerve size and preimplantation speech perception test scores were significant predictors of the postimplantation speech perception test scores. The chance of cochlear nerve deficiency increased progressively from CVM type A to type D. CONCLUSION: The new classification of CVM based on the morphology of the cochlea and the modiolus is simple and easy to use, and correlated well with postimplantation speech perception ability and cochlear nerve status. This simple classification of CVM using TBCT with cochlear nerve assessment by magnetic resonance imaging is helpful in the preoperative evaluation of children with CVM.

Long-term outcomes in children with swallowing dysfunction.

PURPOSE: To evaluate swallowing function using a videofluoroscopic swallow study (VFSS), and to identify factors related to long-term swallowing function in children with swallowing dysfunction. METHODS: Ninety children, aged 1-120 months (mean 27.5 months) were randomly selected from among children referred for the evaluation of swallowing dysfunction. We retrospectively reviewed the charts, and long-term outcomes were tracked up to 5 years. RESULTS: Baseline American Speech-Language-Hearing Association National Outcome Measurement System (ASHA NOMS) scale was 3.4 ± 2.5. Supraglottic penetration and subglottic aspiration comfirmed by VFSS were detected in 30 children. After follow-up, oral feeding was possible in 74 patients, and the ASHA NOMS swallowing scale improved significantly, from 3.4 ± 2.5 to 5.8 ± 2.0. Baseline VFSS severity, serum albumin concentration, baseline weight percentile and neurologic conditions were significantly correlated with long-term swallowing function. CONCLUSIONS: The long-term outcomes in children with swallowing dysfunction were favorable, and baseline videofluoroscopic severity was significantly correlated with long-term swallowing function.

AAC intervention using a VOCA for deaf children with multiple disabilities who received cochlear implantation.

OBJECTIVES: The aim of this study was to examine the efficacy of a new habilitation approach, augmentative and alternative communication (AAC) intervention using a voice output communication aid (VOCA), in improving speech perception, speech production, receptive vocabulary skills, and communicative behaviors in children with cochlear implants (CIs) who had multiple disabilities. METHODS: Five children with mental retardation and/or cerebral palsy who had used CIs over two years were included in this study. Five children in the control group were matched to children who had AAC intervention on the basis of the type/severity of their additional disabilities and chronological age. They had limited oral communication skills after cochlear implantation because of their limited cognition and oromotor function. The children attended the AAC intervention with parents once a week for 6 months. We evaluated their performance using formal tests, including the monosyllabic word tests, the articulation test, and the receptive vocabulary test. We also assessed parent-child interactions. We analyzed the data using a one-group pretest and posttest design. RESULTS: The mean scores of the formal tests performed in these children improved from 26% to 48% in the phoneme scores of the monosyllabic word tests, from 17% to 35% in the articulation test, and from 11 to 18.4 in the receptive vocabulary test after AAC intervention (all p < .05). Some children in the control group showed improvement in the speech perception, speech production, and receptive vocabulary tests for 6 months, but the differences did not achieve statistical significance (all p > .05). The frequency of spontaneous communicative behaviors (i.e., vocalization, gestures, and words) and imitative words significantly increased after AAC intervention (p < .05). CONCLUSIONS: AAC intervention using a VOCA was very useful and effective on improving communicative skills in children with multiple disabilities who had very limited oral communication skills after cochlear implantation.

Auditory neuropathy spectrum disorder: predictive value of radiologic studies and electrophysiologic tests on cochlear implant outcomes and its radiologic classification.

CONCLUSION: The width of the bony cochlear nerve canal (BCNC) and the size of the cochlear nerve are reliable predictors of long-term speech perception abilities for children with auditory neuropathy spectrum disorder (ANSD) after cochlear implantation (CI). In addition, electrical stapedial reflex (ESR) and electrical compound action potential (ECAP) also have considerable value in predicting postoperative speech perception abilities in these children. OBJECTIVES: To assess whether speech perception abilities after CI in children with ANSD can be predicted from the results of radiologic studies and electrophysiologic tests. METHODS: Fifteen children with ANSD underwent CI. The width of the BCNC and the size of the cochlear nerve were measured using preoperative CT and MRI. The results of early postoperative ESR, ECAP, and implant evoked electrical auditory brainstem response were reviewed. The latest speech perception test scores were also reviewed. RESULTS: Radiologic findings of normal BCNC and normal cochlear nerve correlated with excellent speech perception abilities after CI. A narrow or obliterated BCNC and a deficient cochlear nerve correlated with poor speech perception abilities. Children with good speech perception abilities showed robust responses on ESR and ECAP, but there were no responses from any of the children with poor speech perception abilities.

Functional benefits of sequential bilateral cochlear implantation in children with long inter-stage interval between two implants.

OBJECTIVES: Older children are increasingly deriving binaural benefits from sequential bilateral cochlear implantation, and this procedure should be considered by experienced cochlear implant centers. This study aimed to identify the influence of a long inter-stage interval between two implants in older children. Speech perception and everyday listening performance were investigated and analyzed according to the length of the inter-stage interval. STUDY DESIGN AND SETTINGS: Forty-two children who received sequential bilateral cochlear implantation participated in this study. Their average ages at the first and second implantation were 4.2 and 9.7 years, respectively. All subjects acquired excellent speech performance from their first implant, and the mean inter-stage interval was 5.5 years. Speech perception in quiet was assessed by formal speech measures, and postoperative performance using the second implant only was compared with the preoperative performance. Speech perception in noise test was administered using three noise directions with noise (+10 dB signal-to-noise ratio) from front and 90° to each side, and the change in performance using the first implant only and both implants were analyzed across the three noise directions. Subjects were divided into three groups according to their inter-stage interval (group I, 3-4.9 years; group II, 5-6.9 years; and group III, 7-9.9 years), and the test results were compared between the groups. Functional hearing benefits in daily life were measured by a questionnaire before and after bilateral cochlear implantation. RESULTS: The speech perception abilities in quiet using the second implant only improved quickly and were similar to those using the first implant only within 1 year after the second implantation. The scores for the monosyllabic word test (phoneme: p=0.052; word: p=0.125) and common phrases sentence test (p=0.062) 6 month after the second implantation, and the Categories of Auditory Performance score (p=1.000) 1 year after the second implantation using the second implant only did not differ significantly from those using the first implant only. Speech perception was significantly better using both implants than using the first implant in all three noise conditions (speech and noise in front: p=0.004; speech in front and noise to the first implant: p=0.003; speech in front and noise to the second implant: p<0.001), and the effect of noise direction was negligibly small. No salient influence of inter-stage interval was observed in both quiet and noise tests. The second and third groups with longer inter-stage intervals (>5 years) achieved performance close to the level of the first group with a shorter interval. These subjects obtained significantly better functional hearing benefits in the everyday environment with bilateral implants compared with the first implant (p=0.018). CONCLUSION: The subjects in this study showed rapid postoperative progression within 6 months after the second implantation, and more listening benefits in noise and daily life with bilateral implants. This group of older children, who were good performers with the first implant, developed auditory perceptual competence in the second ear and achieved functional binaural benefits with their two implants. Sequential bilateral cochlear implantation should be recommended to this group of older children despite a long inter-stage interval between two implants.

Cortical auditory evoked potential in aging: effects of stimulus intensity and noise.

OBJECTIVE: Older adults often have more difficulty understanding speech than younger adults do, particularly in the presence of noise. Such age-related speech perception difficulties may be related to declines in central auditory processing. Additionally, it has been hypothesized that impaired auditory processing might be related to neural dysynchrony. The purpose of this study was to examine the effects of stimulus intensity and noise on the N1-P2 response in younger and older normal-hearing adults. METHODS: Eight younger and 8 older normal-hearing adults participated in this study. Brief 100-ms tones (1.0 kHz, 100-60 dB SPL) in quiet and in continuous broadband noise (70 dB SPL) were used to evoke the N1-P2 responses. The N1-P2 components were analyzed as a function of stimulus intensity in both groups. RESULTS: N1 latencies to tones in quiet for older adults were delayed only at 60 dB SPL compared with those for younger adults. Additionally, N1 latencies to tones in noise were prolonged in older adults compared with those in younger adults even at 70 dB SPL (SNR = 0). No significant age effects were observed for the P2 latencies and N1-P2 amplitudes between the groups. CONCLUSION: N1 latency to tones with lower intensity and noise were delayed in older adults compared with those in younger adults. These stimulus intensity and noise issues can affect synchronized neural activity underlying the auditory processing and may provide a partial explanation for the difficulties shown by older adults in understanding speech.

MAP optimization as a predictor of cochlear implant outcomes in children with narrow internal auditory canal.

OBJECTIVES: The purposes of this study were to investigate the auditory performance and MAP characteristics of implanted children with narrow internal auditory canal (IAC), and to examine the clinical usefulness of MAP optimization as a predictor of their cochlear implant (CI) outcomes by analyzing their auditory performance and habilitation methods in relation to MAP optimization. METHODS: Eight children with narrow IAC who had used a CI over 3 years were included. We retrospectively examined their auditory performance and MAPs. Auditory performance was measured by the Categories of Auditory Performance (CAP) and monosyllabic word tests before and after implantation. The relationship between auditory performance and MAP parameters was explored, and their habilitation methods were analyzed. RESULTS: Mean CAP scores improved from .25 preoperatively to 3.5 3 years postoperatively. Mean scores for monosyllabic word tests improved from 0% preoperatively to 27.8% 3 years postoperatively. The children used MAPs with a wider pulse width than the default setting. Four children using optimal MAPs achieved open-set speech perception, so were trained in the oral approach. The other four using suboptimal MAPs because of non-auditory stimulation achieved no open-set speech perception, so were trained in the total communication approach. CONCLUSIONS: MAP optimization had a predictable value in determining the postoperative performance of children with narrow IAC who received a CI. The most suitable habilitation method can be determined early after implantation by identifying the presence of MAP optimization.

Cochlear implantation in children with cochlear aplasia.

CONCLUSION: Children with cochlear aplasia can achieve favorable speech perception abilities from cochlear implantation (CI) by inserting an electrode array into the vestibule if an audiological response is reliably demonstrated before surgery by behavioral audiometry and objective measures. OBJECTIVES: The purpose of this study was to evaluate the surgical outcome of CI in children with cochlear aplasia. METHODS: The medical records of 454 children who underwent CI at the Dong-A University Hospital between January 1994 and September 2011 were reviewed. The prevalence of cochlear aplasia and the preoperative evaluations, operative findings, and postoperative speech perception abilities of implanted children with cochlear aplasia were evaluated. RESULTS: The implanted children with cochlear aplasia accounted for 2% of those with inner ear malformations and 0.4% of all pediatric cochlear implantees. They showed audiological responses in preoperative electrophysiologic tests, and the eighth nerve was present in magnetic resonance imaging. The electrode array was inserted into the vestibule through an oval window after removing the stapes or through a transmastoid labyrinthotomy site. Electrical compound action potential and electrical auditory brainstem response tests showed clear neural responses after implantation. The hearing thresholds of the implanted ear improved to 25 dB HL and the children achieved significant open set speech perception abilities.

Changes in the hearing thresholds of infants who failed the newborn hearing screening test and in infants treated in the neonatal intensive care unit.

OBJECTIVES: The aim of this study was to investigate changes in the hearing thresholds during the first year of life in infants who failed the newborn hearing screening (NHS) test and of infants treated in the neonatal intensive care unit (NICU). METHODS: From March 2007 to November 2010, 193 healthy infants who failed the NHS test and 51 infants who were treated in the NICU were referred for evaluation of hearing acuity. Their hearing was evaluated using impedance audiometry, auditory brainstem response (ABR), and otoacoustic emission before 6 months of age, and follow-up hearing tests were administered before 12 months of age. Changes in their hearing thresholds were then analyzed. RESULTS: Of the 193 healthy infants who failed the NHS test, 60 infants (31%) had normal hearing acuity, 126 infants (65%) had sensorineural hearing loss (SNHL, ABR threshold ≥40 dB) and 7 infants (4%) had auditory neuropathy (AN). On the follow-up hearing tests, which were conducted in 65 infants, 6 infants showed a hearing threshold deterioration of more than 20 dB, and 19 infants showed a hearing threshold improvement of more than 20 dB. Of the 51 infants who were treated in the NICU, 38 infants (75%) had normal hearing acuity, 12 infants (24%) had SNHL, and one infant (2%) had AN. In the follow-up hearing tests, which were performed in 13 infants, one infant with normal hearing progressed to severe hearing loss. Five infants who had SNHL showed a hearing threshold improvement of more than 20 dB, and 4 infants recovered to normal hearing. CONCLUSION: The hearing thresholds of infants with congenital SNHL can change during the first year of life; therefore, the importance of administration of follow-up hearing tests is emphasized. Irreversible intervention such as cochlear implantation should be considered with great caution within the first year after birth.

Modulation of cortical activity after anodal transcranial direct current stimulation of the lower limb motor cortex: a functional MRI study.

BACKGROUND AND OBJECTIVES: Functional magnetic resonance imaging (fMRI) has shown that transcranial direct current stimulation (tDCS) of the hand motor cortex modulates cortical activity of the healthy human brain. However, few studies have assessed the effects of tDCS on the leg motor cortex. We therefore used fMRI to examine the modulating effects of tDCS on lower limb motor cortex responses. METHODS: In this sham-controlled case-control study, 11 subjects were exposed to active anodal (n = 6) or sham (n = 5) stimulation, with the anode being positioned on the leg motor cortex of the right hemisphere. Each tDCS was delivered for 15 minutes at 2 mA, with each subject receiving a total of four stimulatory sessions on consecutive days. Cortical activity was measured before the first and after the fourth session by fMRI, and changes in cortical activity were calculated. RESULTS: Anodal tDCS increased activation of the ipsilateral supplementary motor area and lowered the extent of activation of both anterior cingulate gyri, the right middle and superior temporal gyri, the middle and superior frontal gyri, and the primary and secondary somatosensory cortices. CONCLUSIONS: Anodal tDCS increased corticospinal excitability of the lower limb motor cortex in healthy subjects, suggesting that multiple brain cortical areas may be associated with leg motor performance via involvement of variable corticocortical connections.

Recovery function of electrically evoked compound action potential in implanted children with auditory neuropathy: preliminary results.

CONCLUSION: The results of this study show that the temporal processing ability in children with auditory neuropathy (AN) can be restored to some degree by electrical stimulation through a cochlear implant. In addition, the electrically evoked compound action potential (ECAP) may be a useful index to predict outcomes in implanted children with AN. OBJECTIVES: The purpose of this study was to evaluate restoration of the temporal processing abilities in implanted children with AN using ECAP recovery function and speech perception. METHODS: Ten children who had received cochlear implantations participated in this study, including six with AN and four with sensorineural hearing loss (SNHL). ECAP recovery functions were measured, and the slopes of ECAP recovery functions in implanted children with AN were compared with those of implanted children with SNHL. Open-set speech perception test scores of implanted children with AN were compared with those of 78 implanted children with SNHL. RESULTS: The slopes of the ECAP recovery function in children with AN did not differ significantly from those in children with SNHL. The group of children with robust ECAPs showed good postoperative performance. However, the group with no ECAPs showed poor performance.

Effect of virtual reality on cognition in stroke patients.

OBJECTIVE: To investigate the effect of virtual reality on the recovery of cognitive impairment in stroke patients. METHOD: Twenty-eight patients (11 males and 17 females, mean age 64.2) with cognitive impairment following stroke were recruited for this study. All patients were randomly assigned to one of two groups, the virtual reality (VR) group (n=15) or the control group (n=13). The VR group received both virtual reality training and computer-based cognitive rehabilitation, whereas the control group received only computer-based cognitive rehabilitation. To measure, activity of daily living cognitive and motor functions, the following assessment tools were used: computerized neuropsychological test and the Tower of London (TOL) test for cognitive function assessment, Korean-Modified Barthel index (K-MBI) for functional status evaluation, and the motricity index (MI) for motor function assessment. All recruited patients underwent these evaluations before rehabilitation and four weeks after rehabilitation. RESULTS: The VR group showed significant improvement in the K-MMSE, visual and auditory continuous performance tests (CPT), forward digit span test (DST), forward and backward visual span tests (VST), visual and verbal learning tests, TOL, K-MBI, and MI scores, while the control group showed significant improvement in the K-MMSE, forward DST, visual and verbal learning tests, trail-making test-type A, TOL, K-MBI, and MI scores after rehabilitation. The changes in the visual CPT and backward VST in the VR group after rehabilitation were significantly higher than those in the control group. CONCLUSION: Our findings suggest that virtual reality training combined with computer-based cognitive rehabilitation may be of additional benefit for treating cognitive impairment in stroke patients.

The relationship between electrically evoked compound action potential and speech perception: a study in cochlear implant users with short electrode array.

OBJECTIVES: To determine the extent to which electrically evoked compound action potential (ECAP) measurements were related with speech perception performance in implant users with a short electrode array and to investigate the relationship between ECAP measures and performance according to specific devices. DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS: Seventeen Hybrid cochlear implant users were tested in this study. Subjects were divided into 2 groups: 8 using the Nucleus Hybrid M and 9 using the Nucleus Hybrid RE. In addition, 21 Nucleus Freedom long electrode implant (CI24RE) users also were tested to compare with the results of the old device (CI24M). MAIN OUTCOME MEASURES: ECAP growth functions were recorded using either an interphase gap (IPG) of 8 or 45 mus. We then calculated the slope of the growth function and changes in sensitivity with IPG. For each subject, these measures were compared with performance on tests of word recognition. RESULTS: The changes in sensitivity using 2 IPGs showed no correlation with the results of word recognition test in Hybrid cochlear implant users. In contrast, relatively strong correlations have been found between the slope of ECAP growth functions and performance on word recognition test. Additionally, when we separate the results of Hybrid M and RE, the slopes of ECAP growth functions from only Hybrid RE CI recipients were significantly correlated with speech performance. The slopes of ECAP growth function in CI24RE users with long electrode also were significantly correlated with performance. However, comparing between 2 independent correlations in RE devices, correlation was higher in Hybrid RE group. CONCLUSION: The results presented in this article support the view that slope of the ECAP growth can show significant correlation to performance with a cochlear implant. Furthermore, these results suggest that the strength of the correlation may be related to the specific device. These results suggest that ECAP measures may be useful in developing a test to predict outcomes with the implant.