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Latency of auditory evoked potential monitoring the effects of general anesthetics on nerve fibers and synapses. Sci Rep 2015; 5:12730. [PMID: 26246365 PMCID: PMC4526847 DOI: 10.1038/srep12730] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 07/06/2015] [Indexed: 11/24/2022] Open
Abstract
Auditory evoked potential (AEP) is an effective index for the effects of general anesthetics. However, it’s unknown if AEP can differentiate the effects of general anesthetics on nerve fibers and synapses. Presently, we investigated AEP latency and amplitude changes to different acoustic intensities during pentobarbital anesthesia. Latency more regularly changed than amplitude during anesthesia. AEP Latency monotonically decreased with acoustic intensity increase (i.e., latency-intensity curve) and could be fitted to an exponential decay equation, which showed two components, the theoretical minimum latency and stimulus-dependent delay. From the latency-intensity curves, the changes of these two components (∆L and ∆I) were extracted during anesthesia. ∆L and ∆I monitored the effect of pentobarbital on nerve fibers and synapses. Pentobarbital can induce anesthesia, and two side effects, hypoxemia and hypothermia. The hypoxemia was not related with ∆L and ∆I. However, ∆L was changed by the hypothermia, whereas ∆I was changed by the hypothermia and anesthesia. Therefore, we conclude that, AEP latency is superior to amplitude for the effects of general anesthetics, ∆L monitors the effect of hypothermia on nerve fibers, and ∆I monitors a combined effect of anesthesia and hypothermia on synapses. When eliminating the temperature factor, ∆I monitors the anesthesia effect on synapses.
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Developmental study of the distribution of hypoxia-induced factor-1 alpha and microtubule-associated protein 2 in children’s brainstem: Comparison between controls and cases with signs of perinatal hypoxia. Neuroscience 2014; 271:77-98. [DOI: 10.1016/j.neuroscience.2014.04.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/21/2014] [Accepted: 04/08/2014] [Indexed: 11/20/2022]
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Smit AL, Seehase M, Stokroos RJ, Jellema RK, Felipe L, Chenault MN, Anteunis LJC, Kremer B, Kramer BW. Functional impairment of the auditory pathway after perinatal asphyxia and the short-term effect of perinatal propofol anesthesia in lambs. Pediatr Res 2013; 74:34-8. [PMID: 23575875 DOI: 10.1038/pr.2013.64] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 12/14/2012] [Indexed: 11/09/2022]
Abstract
BACKGROUND Sensorineural hearing loss (SNHL) is a common feature in the postasphyxial syndrome in newborns. Several anesthetic drugs have been proposed to attenuate secondary neuronal injury elicited by hypoxia-ischemia. We hypothesized that propofol anesthesia reduces auditory impairment after perinatal asphyxia in comparison with isoflurane. METHODS Twenty-three pregnant ewes were randomized to propofol or isoflurane anesthesia and sedation. The lambs underwent in utero umbilical cord occlusion (isoflurane n = 5; propofol n = 7) and were compared with sham-treated animals (isoflurane n = 5; propofol n = 6) at a gestational age of 133 d. For 8 h after delivery by cesarean section, repeated auditory brainstem responses (ABRs) were recorded to obtain hearing thresholds, peak amplitudes, latencies, and interpeak latencies. RESULTS Significantly elevated mean thresholds, diminished amplitudes, and elevated latencies were observed in the asphyxia group relative to the control group through the observation period. Comparison of anesthetic treatment in the asphyxia group revealed a significantly lower elevation in threshold and less impairment in the ABR amplitudes and latencies during propofol anesthesia as compared with isoflurane anesthesia. CONCLUSION Our results support the hypothesis that anesthesia with propofol has a preventive effect on the functional changes to the auditory pathway in the event of perinatal asphyxia.
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Affiliation(s)
- Adriana L Smit
- Department of Otorhinolaryngology/Head and Neck Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands.
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Jiang ZD, Wilkinson AR. Relationship between brainstem auditory function during the neonatal period and depressed Apgar score. J Matern Fetal Neonatal Med 2010; 23:973-9. [PMID: 19903110 DOI: 10.3109/14767050903410672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To understand whether infants with depressed Apgar scores are at high risk of brainstem auditory impairment, we examined the relationship between brainstem auditory function during the neonatal period and depressed Apgar score. METHODS Brainstem auditory evoked responses (BAERs) were recorded from day 1 to day 30 in 145 term infants with Apgar scores < or = 6. RESULTS For 1-min Apgar score none of BAER response wave latencies and interpeak intervals during the first 15 days correlated significantly with the score. On day 30, all wave latencies but no intervals correlated negatively with the score (all p < 0.05). For 5-min Apgar score, only on day 3 wave V latency and I-V and III-V intervals correlated negatively with the score (all p < 0.05). For 10-min Apgar score, only III-V interval correlated negatively with the score (p < 0.05). No correlation was found between BAER variables on any other days and 5 and 10-min Apgar scores. Wave V latency and I-V and III-V intervals on day 3 were all significantly longer in infants with 5-min Apgar scores < or = 6 than in those with scores > 6. CONCLUSIONS During the neonatal period, only on day 3 after birth a depressed 5-min Apgar score is an indicator associated with central auditory impairment. A depressed 1-min score may be associated with later peripheral auditory impairment.
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Affiliation(s)
- Ze Dong Jiang
- Neonatal Unit, Department of Paediatrics, John Radcliffe Hospital, Headington, University of Oxford, Oxford, UK.
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Differences in impaired brainstem conduction between neonatal chronic lung disease and perinatal asphyxia. Clin Neurophysiol 2010; 121:725-33. [PMID: 20097607 DOI: 10.1016/j.clinph.2009.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 11/06/2009] [Accepted: 12/08/2009] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To explore any differences in impaired brainstem function between preterm infants with neonatal chronic lung disease (CLD) and term infants after perinatal asphyxia. METHODS Brainstem auditory evoked responses (BAERs) collected using maximum length sequence (MLS) technique were compared at term equivalent age between 43 CLD infants and 117 asphyxiated infants. RESULTS In both CLD and asphyxiated infants there was a significant increase in wave V latency and I-V interval in MLS BAER. CLD infants showed a significant increased III-V interval but a normal I-III interval at all click rates. However, asphyxiated infants showed a significant increase in both III-V and I-III intervals. I-III interval was shorter and III-V/I-III interval ratio was greater in CLD infants than in asphyxiated infants. The slope of I-III interval-rate function was steeper in asphyxiated infants than in CLD infants, while the slope of III-V/I-III interval ratio-rate function was the other way around. CONCLUSIONS CLD infants had a major increase in more central components of MLS BAER, without appreciable abnormality in more peripheral components. However, asphyxiated infants had a significant increase in both central and peripheral components. SIGNIFICANCE Neonatal CLD affects more central regions of the brainstem, whereas perinatal asphyxia affects both peripheral and central regions. This difference, which is likely related to the different nature of hypoxia in CLD and asphyxia, may have some significance for neuroprotective interventions for the two problems.
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Jiang ZD, Brosi DM, Chen C, Wilkinson AR. Brainstem response amplitudes in neonatal chronic lung disease and differences from perinatal asphyxia. Clin Neurophysiol 2009; 120:967-73. [DOI: 10.1016/j.clinph.2009.02.166] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 01/24/2009] [Accepted: 02/16/2009] [Indexed: 11/16/2022]
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Jiang ZD, Brosi DM, Shao XM, Wilkinson AR. Sustained depression of brainstem auditory electrophysiology during the first months in term infants after perinatal asphyxia. Clin Neurophysiol 2008; 119:1496-505. [PMID: 18479964 DOI: 10.1016/j.clinph.2008.03.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 03/10/2008] [Accepted: 03/17/2008] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To gain further insights into the pathophysiological processes of neuronal impairment in neonatal brainstem after perinatal asphyxia. METHODS Maximum-length sequence brainstem auditory-evoked response (MLS BAER) was recorded with clicks at 91, 227, 455 and 910/s on days 1, 3, 5, 7, 10, 15 and 30 after birth in 108 term infants who suffered perinatal asphyxia. Wave amplitude variables in the MLS BAER were analysed in detail at 40 dB above BAER threshold in 86 infants who had no peripheral hearing impairment. RESULTS On day 1 the amplitudes of MLS BAER waves I, III and V were all reduced significantly at all click rates, especially at higher ones (91-910/s, ANOVA P<0.05-0.001). On day 3 these amplitudes were reduced further. On days 5 and 7, the amplitude reduction persisted and did not show any significant further changes. On days 10 and 15 the reduced amplitudes were increased slightly. On day 30 all amplitudes were still reduced significantly (P<0.05-0.0001). During the first month, the reduction of wave amplitudes was more significant for the later MLS BAER components than for the earlier ones, and occurred most significantly at 455 and 910/s clicks. By comparison, the amplitude reduction in conventional BAER was much less significant. CONCLUSIONS During the first month after perinatal asphyxia the amplitudes of MLS BAER waves were reduced significantly and persistently, which was more significant at higher rates of clicks than at lower rates. The reduction is much more persistent than the increase in wave latencies and intervals we previously reported. SIGNIFICANCE There is sustained depression of brainstem auditory electrophysiology, indicating neuronal damage of the auditory brainstem, in infants after perinatal asphyxia. This may have important clinical implications.
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Affiliation(s)
- Ze D Jiang
- Children's Hospital, Fudan University, Shanghai, China.
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8
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Ball KK, Gandhi GK, Thrash J, Cruz NF, Dienel GA. Astrocytic connexin distributions and rapid, extensive dye transfer via gap junctions in the inferior colliculus: implications for [(14)C]glucose metabolite trafficking. J Neurosci Res 2008; 85:3267-83. [PMID: 17600824 PMCID: PMC2819729 DOI: 10.1002/jnr.21376] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The inferior colliculus has the highest rates of blood flow and metabolism in brain, and functional metabolic activity increases markedly in response to acoustic stimulation. However, brain imaging with [1- and 6-(14)C]glucose greatly underestimates focal metabolic activation that is readily detected with [(14)C]deoxyglucose, suggesting that labeled glucose metabolites are quickly dispersed and released from highly activated zones of the inferior colliculus. To evaluate the role of coupling of astrocytes via gap junctions in dispersal of molecules within the inferior colliculus, the present study assessed the distribution of connexin (Cx) proteins in the inferior colliculus and spreading of Lucifer yellow from single microinjected astrocytes in slices of adult rat brain. Immunoreactive Cx43, Cx30, and Cx26 were heterogeneously distributed; the patterns for Cx43 and Cx 30 differed and were similar to those of immunoreactive GFAP and S100beta, respectively. Most Cx43 was phosphorylated in resting and acoustically stimulated rats. Dye spreading revealed an extensive syncytial network that included thousands of cells and perivasculature endfeet; with 8% Lucifer yellow VS and a 5-min diffusion duration, about 6,100 astrocytes (range 2,068-11,939) were labeled as far as 1-1.5 mm from the injected cell. The relative concentration of Lucifer yellow fell by 50% within 0.3-0.8 mm from the injected cell with a 5-min diffusion interval. Perivascular dye labeling was readily detectable and often exceeded dye levels in nearby neuropil. Thus, astrocytes have the capability to distribute intracellular molecules quickly from activated regions throughout the large, heterogeneous syncytial volume of the inferior colliculus, and rapid trafficking of labeled metabolites would degrade resolution of focal metabolic activation.
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Affiliation(s)
- Kelly K. Ball
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Gautam K. Gandhi
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Jarrod Thrash
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Nancy F. Cruz
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Gerald A. Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Correspondence to: Gerald A. Dienel, PhD, Department of Neurology, Slot 830, University of Arkansas for Medical Sciences, 4301 W. Markham St., Shorey Bldg., Room 715, Little Rock, AR 72205.
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Wilkinson AR, Brosi DM, Jiang ZD. Functional impairment of the brainstem in infants with bronchopulmonary dysplasia. Pediatrics 2007; 120:362-71. [PMID: 17671063 DOI: 10.1542/peds.2006-3685] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES To gain new insights into the influence of bronchopulmonary dysplasia on the immature brain and to detect abnormalities, we studied the functional integrity of the brainstem in infants with bronchopulmonary dysplasia. METHODS Forty-one very preterm infants with bronchopulmonary dysplasia were studied at postconceptional ages of 37 to 42 weeks. Brainstem auditory evoked responses were recorded and analyzed by using the maximal length sequence technique. RESULTS Compared with term control subjects, wave V latency in the maximal length sequence brainstem auditory evoked response of the infants with bronchopulmonary dysplasia increased significantly at all 91 to 910 clicks per second rates. Similarly, I-V and particularly III-V interpeak intervals increased significantly. The III-V/I-III interval ratio also increased significantly at all click rates. All of these abnormalities became more significant as the click rate was increased. Compared with healthy, very preterm control subjects, all of these maximal length sequence brainstem auditory evoked response variables increased significantly at all click rates, although the differences between the 2 groups were slightly smaller than those between the infants with bronchopulmonary dysplasia and the term control subjects. The wave I and III latencies and I-III interval in the infants with bronchopulmonary dysplasia did not show any abnormalities. The slopes of the wave V latency-rate function and I-V and particularly III-V interval-rate functions for the infants with bronchopulmonary dysplasia were significantly steeper than those for both term and healthy, very preterm control subjects. The slope of the III-V/I-III interval ratio-rate function for the infants with bronchopulmonary dysplasia was also significantly steeper than those for the 2 control groups. CONCLUSIONS The results suggest poor myelination and synaptic function of the brainstem in infants with bronchopulmonary dysplasia, resulting in impaired functional integrity. In comparison, peripheral neural function was relatively intact.
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Affiliation(s)
- Andrew R Wilkinson
- Neonatal Unit, Department of Paediatrics, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom
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Jiang ZD, Yin R, Wilkinson AR. Brainstem auditory evoked responses in very low birthweight infants with chronic lung disease. Eur J Paediatr Neurol 2007; 11:153-9. [PMID: 17276109 DOI: 10.1016/j.ejpn.2006.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 09/25/2006] [Accepted: 12/05/2006] [Indexed: 11/19/2022]
Abstract
UNLABELLED Very low birthweight (VLBW) infants who had prolonged oxygen dependence due to chronic respiratory problems, typically neonatal chronic lung disease (CLD), are at high risk of neurodevelopmental impairment. To assess the effect of CLD on neonatal auditory function we studied brainstem auditory evoked response (BAER) in VLBW infants who suffered CLD but no other major perinatal complications or problems. At 37-42 week postconceptional age, the latencies of waves I, III and V in CLD infants were all significantly longer than in normal term infants (all p<0.001). The differences between CLD infants and the term controls were greater for the later waves than for the earlier waves. Abnormally prolonged wave latency (>2.5 SD of the mean measurement) was seen in 7 (21.2%) CLD infants for wave I, suggesting peripheral auditory impairment, 8 (24.2%) for wave III and 14 (42.4%) for wave V. I-V interval in CLD infants was significantly longer than in the term controls (p<0.001). Seven (21.2%) infants had abnormally prolonged I-V interval, suggesting brainstem or central auditory impairment. Of these infants, 2 had both prolonged wave latencies and prolonged I-V interval, suggesting both peripheral and central auditory impairment. Similar abnormalities were found in CLD infants when compared with the BAER in birthweight- and age-matched healthy VLBW infants without CLD. CONCLUSION Neonatal auditory function is impaired, both peripherally and centrally, at term age in VLBW infants who suffer neonatal CLD.
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Affiliation(s)
- Ze D Jiang
- Children's Hospital, Shanghai Medical University, Shanghai, China.
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Jiang ZD, Shao XM, Wilkinson AR. Changes in BAER amplitudes after perinatal asphyxia during the neonatal period in term infants. Brain Dev 2006; 28:554-9. [PMID: 16647830 DOI: 10.1016/j.braindev.2006.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Revised: 03/14/2006] [Accepted: 03/14/2006] [Indexed: 10/24/2022]
Abstract
We recorded serially brainstem auditory evoked response (BAER) during the neonatal period in term infants who suffered perinatal asphyxia. The amplitudes of BAER components was analysed at 40 dB above BAER threshold of each subject who had a threshold<or=25 dB nHL. No apparent changes in the amplitudes of waves I and III during the first 5 days after birth. The two wave amplitudes were slightly reduced thereafter. On day 30, the amplitudes were slightly smaller than in normal controls. No statistical significant differences were found in the two amplitudes between the infants after asphyxia and the controls on any days studied. In contrast, wave V amplitude showed a trend of reduction during the whole neonatal period. The amplitude was reduced slightly on the first day after birth, but reduced further on day 3 (ANOVA, P<0.01). Thereafter, the reduction persisted without any significant change. On day 30, wave V amplitude remained significantly smaller than in the controls (P<0.001). Compared to the controls, V/I amplitude ratio was slightly smaller during the neonatal period, but V/III amplitude ratio was significantly smaller on most of the days studied (P<0.05-0.01). The persistent reduction of wave V amplitude suggests a sustained neuronal damage of the auditory brainstem in infants after perinatal asphyxia.
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Affiliation(s)
- Ze D Jiang
- Children's Hospital, Fudan University, Shanghai, China.
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Jiang ZD, Brosi DM, Wilkinson AR. Brain-stem auditory function in very preterm infants with chronic lung disease: Delayed neural conduction. Clin Neurophysiol 2006; 117:1551-9. [PMID: 16759903 DOI: 10.1016/j.clinph.2006.04.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 04/21/2006] [Accepted: 04/25/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To examine brain-stem auditory function at term in very preterm infants who suffered chronic lung disease (CLD). METHODS Brain-stem auditory evoked response (BAER) was recorded at term with clicks in 25 very preterm infants with CLD and no concomitant other major perinatal problems. RESULTS Compared to those in normal term controls, BAER wave V latency and I-V and III-V interpeak intervals in the CLD infants increased significantly (ANOVA P<0.01-0.001). III-V/I-III interval ratio also increased significantly (P<0.01). The latencies of waves I and III did not differ significantly from the controls. However, no abnormalities were found in BAER wave amplitudes. These BAER findings, obtained at 21/s clicks, were also seen at the rates 51 and 91/s, although the increase in III-V interval tended to be more significant. Click rate-dependent changes in BAER variables in the CLD infants were generally similar to the controls, with slight differences. CONCLUSIONS BAER components, mainly reflecting central auditory function, increased significantly. The increase in wave V latency and I-V interval is due to the increase in III-V interval. SIGNIFICANCE Neural conduction in the more central portion of the brain-stem auditory pathway is delayed and thus brain-stem auditory function is impaired in CLD infants.
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Affiliation(s)
- Ze D Jiang
- Children's Hospital, Shanghai Medical University, Shanghai, China.
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Jiang ZD, Shao XM, Wilkinson AR. Brainstem auditory-evoked responses in full-term newborn infants with temporary low Apgar score. Acta Otolaryngol 2005; 125:163-8. [PMID: 15880947 DOI: 10.1080/00016480410017684] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
CONCLUSIONS No abnormalities, with the exception of maturational changes, in BAER were found during the neonatal period. The results suggest that a temporary low Apgar score is not accompanied by any significant auditory impairment. OBJECTIVE To examine brainstem auditory function in newborn infants with a temporary low Apgar score but no clinical signs of hypoxic-ischaemic encephalopathy (HIE). MATERIAL AND METHODS The subjects were 36 full-term infants with Apgar scores of < or =7 at 1 and/or 5 min and > or =8 at 10 min but without HIE. The brainstem auditory-evoked response (BAER) was serially recorded at click rates of 21, 51 and 91/s on Days 1, 3, 5, 7 and 30 after birth. RESULTS On Day 1 and Days 3-5, the latencies of waves I, III and V tended to increase slightly at all click rates but did not differ significantly from normal control values. Thereafter, all latencies tended to decrease, reaching control values on Day 30. The I-V interval was similar to the control values at all click rates during the first 5 days, tended to decrease from Day 7 and did not differ from the control values on Day 30. There were no significant changes in BAER wave amplitudes at any of the click rates on any day.
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Affiliation(s)
- Ze D Jiang
- Children's Hospital, Shanghai Medical University, Shanghai, People's Republic of China.
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Jiang ZD, Yin R, Shao XM, Wilkinson AR. Brain-stem auditory impairment during the neonatal period in term infants after asphyxia: dynamic changes in brain-stem auditory evoked response to clicks of different rates. Clin Neurophysiol 2004; 115:1605-15. [PMID: 15203061 DOI: 10.1016/j.clinph.2004.02.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2004] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To explore dynamic changes in brain-stem auditory electrophysiology during the neonatal period in term infants after perinatal asphyxia. METHODS Sixty-eight term newborn infants who suffered asphyxia were studied on days 1, 3, 5, 7, 14 and 30 after birth. Brain-stem auditory evoked response (BAER) was recorded with clicks, delivered at 21, 51 and 91 s(-1) and > or =40 dB above BAER threshold of each subject. RESULTS During the neonatal period wave I latency in the infants after asphyxia increased slightly while later BAER components changed more significantly. On the first day after birth wave III and V latencies and I-V and III-V intervals increased significantly at all rates of clicks (ANOVA P<0.01-0.001). On day 3, the latencies and intervals increased further. III-V/I-III interval ratio increased at 51 and 91 s(-1), suggesting a relatively more significant increase in III-V interval than in I-III interval at higher rates. Thereafter, wave III and V latencies and all intervals decreased progressively, although these BAER variables were still significantly longer than in normal controls on days 5 and 7 (P<0.05-0.001) On day 30, all latencies and intervals approached near normal values, with a slight increase in wave V latency and I-V and III-V intervals at 51 and 91 s(-1). CONCLUSIONS Perinatal asphyxia has a major effect on central auditory function, resulting in acute impairment. The impairment progresses during the first 3 days and then tends towards recovery. By 1 month the impaired auditory function has largely returned to normal. Significant increase in click rates can moderately improve the detection of auditory impairment. SIGNIFICANCE After perinatal asphyxia early detection of hypoxic-ischaemic damage to the central auditory system and initialisation of neuroprotective and therapeutic measures during the first hours after birth are critical to prevent or reduce deterioration of central impairment.
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Affiliation(s)
- Ze D Jiang
- Children's Hospital, Shanghai Medical University, Shanghai, China.
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Jiang ZD, Brosi DM, Wang J, Xu X, Chen GQ, Shao XM, Wilkinson AR. Time course of brainstem pathophysiology during first month in term infants after perinatal asphyxia, revealed by MLS BAER latencies and intervals. Pediatr Res 2003; 54:680-7. [PMID: 12869665 DOI: 10.1203/01.pdr.0000084084.62571.12] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Dynamic changes in electrophysiology of brainstem auditory neurons during the first month after birth were studied in 51 term infants after perinatal asphyxia using maximum length sequence brainstem auditory evoked responses. The responses were recorded on d 1, 3, 5, 7, 10, 15, and 30 after birth. On d 1, wave III and V latencies and all interpeak intervals increased significantly at all repetition rates of clicks used (91-910/s), especially the higher rates (ANOVA, p < 0.05-0.0001). On d 3, all these latencies and intervals increased further and differed more significantly from the normal control subjects. Thereafter, the latencies and intervals decreased progressively. On d 7, wave V latency and all intervals still differed significantly from the control subjects. These dynamic changes were more significant at higher rates of clicks than at lower rates. On d 10 and 15, all intervals decreased significantly. On d 30, all wave latencies decreased to the values in the normal control subjects on the same day. The intervals also approached normal values, although the III-V and I-V intervals still increased slightly. These results indicate that hypoxic-ischemic brain damage persists during the first week, with a peak on d 3, and recovers progressively thereafter. By 1 mo, the damage has largely returned to normal. Maximum length sequence brainstem auditory evoked responses results correlated well with the stage of hypoxic-ischemic encephalopathy during the first week. The present study revealed a general time course of brainstem pathophysiology after asphyxia, although there were individual variations. Our findings can be used as a reference to monitor cerebral function and help judge the value of neuroprotective or therapeutic interventions. The first week, particularly the first 3 d, is a critical period of hypoxic-ischemic brain damage, and early intervention may prevent or reduce deterioration of the damage.
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Affiliation(s)
- Ze D Jiang
- Neonatal Unit, Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom.
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Nishioka N, Nishina H, Yoshida K, Kinoshita K, Ehara Y. Effect of hypoxia on the auditory system of goat fetuses during extrauterine incubation. J Obstet Gynaecol Res 2003; 29:109-14. [PMID: 12755532 DOI: 10.1046/j.1341-8076.2002.00080.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIM To investigate the effect of hypoxia on the auditory system in fetuses, we attempted to analyze the auditory brainstem response, the middle latency response, and changes of several physiological parameters of goat fetuses during extrauterine incubation. METHODS We conducted extrauterine incubation of five goat fetuses at around 127days of gestation (term = 148 days). Their physiological parameters, such as fetal heart rate, mean blood pressure, flow rate of carotid artery, as well as the auditory brainstem response and middle latency response, were recorded prior to and during hypoxia, and the two sets of data were compared with each other. RESULTS In all five cases, the fetal heart rate decreased from 178 +/- 12.2 b.p.m. to 144 +/- 15.2 b.p.m. during hypoxia, while mean blood pressure and flow rate of carotid artery increased from 37.3 +/- 3.7 mmHg to 43.2 +/- 5.1 mmHg, and from 38.5 +/- 5.5mL/min to 47.0 +/- 5.1 mL/min, respectively. The latency of the auditory brainstem response's wave V and of the middle latency response's Pa wave elongated from 5.24 +/- 0.24 ms to 5.69 +/- 0.20 ms, and from 19.2 +/- 1.6 ms to 20.9 +/- 1.4 ms, respectively. CONCLUSIONS Although fetal compensatory reactions, such as increases in mean blood pressure and flow rate of carotid artery during hypoxia were recognized, elongation of latency, and decrement of amplitude were observed in the auditory brainstem response and middle latency response. These results suggest that hypoxia itself influences the auditory system of the fetus.
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Affiliation(s)
- Nobuko Nishioka
- Department of Obstetrics and Gynecology, Juntendo University School of Medicine, Tokyo, Japan.
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Tomimatsu T, Fukuda H, Endoh M, Mu J, Kanagawa T, Hosono T, Kanzaki T, Doi K, Kubo T, Murata Y. Long-term neuroprotective effects of hypothermia on neonatal hypoxic-ischemic brain injury in rats, assessed by auditory brainstem response. Pediatr Res 2003; 53:57-61. [PMID: 12508082 DOI: 10.1203/00006450-200301000-00012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A method to assess long-term neurofunctional outcome of hypothermia on immature brains has not yet been clearly established. To investigate the effects of hypothermia on long-term neurofunctional outcome, we studied brainstem function using auditory brainstem response in adult rats after neonatal hypoxic-ischemic brain injury. Seven-day-old rats underwent a combination of left common carotid artery ligation and subsequent exposure to 8% O(2) for 1 h (n = 17). The rats were divided into three groups: hypothermia group (n = 6), normothermia group (n = 6), and sham control group (n = 5). During recovery from the hypoxic-ischemic insult, body temperature was reduced to 30 degrees C for 24 h in the hypothermia group, but was kept at 37 degrees C in the normothermia and sham control group. Three months later the rats were assessed by auditory brainstem response, then killed. The normothermia group showed increased III-V latencies and wave V abnormalities. Hypothermia significantly ameliorated wave V abnormalities. Injury to the ipsilateral inferior colliculus was also reduced in the hypothermia group compared with that in the normothermia group, and the degree of damage assessed histologically correlated well with auditory brainstem response findings. The current study demonstrates that postischemic hypothermia may provide effective and long-lasting neurofunctional as well as histopathologic protection to the immature brain.
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Affiliation(s)
- Takuji Tomimatsu
- Department of Obstetrics and Gynecology, Osaka University Faculty of Medicine, 2-2, Yamada-oka, Suita, Osaka, 565-0871, Japan.
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Tomimatsu T, Fukuda H, Endoh M, Mu J, Watanabe N, Kohzuki M, Fujii E, Kanzaki T, Oshima K, Doi K, Kubo T, Murata Y. Effects of neonatal hypoxic-ischemic brain injury on skilled motor tasks and brainstem function in adult rats. Brain Res 2002; 926:108-17. [PMID: 11814412 DOI: 10.1016/s0006-8993(01)03311-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In an attempt to establish more sensitive long-term neurofunctional measurements for neonatal hypoxic-ischemic brain injury, we examined skilled motor task and brainstem functions in adult rats after neonatal cerebral hypoxia-ischemia (H-I), using a staircase test and auditory brainstem response (ABR), respectively. Seven-day-old rats underwent a combination of left common carotid artery ligation and exposure to 8% O(2) for 1 h (n=16). The control animals only received sham operation (n=16). At 3 months of age, the staircase test and ABR were performed. In the staircase test, H-I animals showed marked impairment of skilled forelimb use in the side contralateral to the occluded artery, and the degree of brain damage correlated significantly to skilled forelimb use. In the ABR, H-I animals showed brainstem dysfunction assessed by measuring interpeak latencies for waves III-V and I-V. We also examined the brainstem with antibodies specific for activated caspase-3, a protein involved in initiation of apoptosis, and observed that caspase-3 was activated in the ipsilateral inferior colliculus at 24 h after H-I. The present study shows that both the staircase test and ABR are sensitive and objective long-term neurofunctional measurements that can be used in future studies to assess therapeutic intervention in this neonatal cerebral H-I model.
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Affiliation(s)
- Takuji Tomimatsu
- Department of Obstetrics and Gynecology, Faculty of Medicine, Osaka University School of Medicine, 2-2, Yamada-oka, Suita, Osaka, Japan.
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