Koehler J, Schwarz M, Boor R, Hölker C, Hopf HC, Voth D, Urban PP, Ermert A. Assessment of brainstem function in Chiari II malformation utilizing brainstem auditory evoked potentials (BAEP), blink reflex and masseter reflex. Brain Development. 2000 Oct;22(7):417-20.
Brainstem dysfunction was evaluated in 67 patients with myelomeningocele and Chiari II malformation using brainstem auditory evoked potentials (BAEP), blink reflex (BR) and masseter reflex (MR). Signs and symptoms related to Chiari II malformation were observed in 18 patients while 49 patients had normal brainstem findings. BAEP and BR showed a higher sensitivity of brainstem involvement than MR (BAEP=1.0, BR=0.83, MR=0.50). BR, and in particular, MR were of higher accuracy (BR=0.52, MR=0.72) than BAEP (0.39) in separating patients with brainstem signs and symptoms related to Chiari II malformation. We feel that this is due to anatomic and physiologic peculiarities of the brainstem structures mediating BR and MR. Our results suggest that brainstem reflexes can support the decision of further treatment.
PMID: 11102725
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Showing posts with label Brainstem auditory evoked potentials. Show all posts
Showing posts with label Brainstem auditory evoked potentials. Show all posts
Wednesday, January 30, 2008
Brain stem auditory-evoked potentials in meningomyelocele. Natural history of Chiari II malformations
Nishimura T, Mori K, Uchida Y, Ohira T, Tamura K. Brain stem auditory-evoked potentials in meningomyelocele. Natural history of Chiari II malformations. Child's Nervous System. 1991 Oct;7(6):316-26. Review.
Brain stem auditory-evoked potentials (BAEPs) were recorded in 30 patients with meningomyelocele and shunted hydrocephalus ranging in age from birth to 33 years. Twenty-two of them had Chiari II malformation, one of which was symptomatic. In 22 cases, including 15 with Chiari II malformation, BAEPs were recorded repeatedly after periods ranging from 18 months to 7 years. The results were as follows: (1) III-V interpeak latency (IPL) decreased progressively from prolonged to the normal range with growth until 25 years of age; (2) I-III IPL tended to prolong gradually from the normal range; (3) these findings may indicate that the natural history of Chiari II malformation is delayed maturation of the brain stem and intensification in the elongation and stretching of the hindbrain and lower cranial nerves.
PMID: 1764707
Brain stem auditory-evoked potentials (BAEPs) were recorded in 30 patients with meningomyelocele and shunted hydrocephalus ranging in age from birth to 33 years. Twenty-two of them had Chiari II malformation, one of which was symptomatic. In 22 cases, including 15 with Chiari II malformation, BAEPs were recorded repeatedly after periods ranging from 18 months to 7 years. The results were as follows: (1) III-V interpeak latency (IPL) decreased progressively from prolonged to the normal range with growth until 25 years of age; (2) I-III IPL tended to prolong gradually from the normal range; (3) these findings may indicate that the natural history of Chiari II malformation is delayed maturation of the brain stem and intensification in the elongation and stretching of the hindbrain and lower cranial nerves.
PMID: 1764707
Electrophysiological studies on brainstem function in patients with myelomeningocele
Mori K, Nishimura T. Electrophysiological studies on brainstem function in patients with myelomeningocele. Pediatric Neurosurgery. 1995;22(3):120-31.
We investigated the brainstem auditory evoked potentials (BAEPs), somatosensory evoked potentials (SEPs), and electrically elicited blink reflexes (BRs) to evaluate the brainstem function in 31 patients with meyelomeningocele (MMC) including 22 with Chiari type-II malformation. The I-III interpeak latency (IPL) of the BAEPs and the N9-N13 IPL of the SEPs tended to become gradually prolonged from the normal range with increasing age. The III-V IPL of the BAEPs and the N13-N20 IPL of the SEPs were initially prolonged and decreased progressively to the normal range. These findings indicated a gradual latency shortening of the brainstem components and latency prolongation of the peripheral components. Thus, while primary brainstem dysfunction may improve with age, secondary dysfunction due to stretching and elongation of the lower cranial nerves and cervical nerve roots may intensify. The BRs showed an abnormal R2 in 90% of the cases, disclosing subclinical lesions in the medulla oblongata which were not detected by BAEPs alone. BAEPs, SEPs and BRs were combined to yield a functional evaluation of the brainstem and lower cranial nerves that could not be done by magnetic resonance imaging alone. No close relation was found between electrophysiological abnormalities and the degree of hindbrain anomaly by neuroimaging.
PMID: 7786804
We investigated the brainstem auditory evoked potentials (BAEPs), somatosensory evoked potentials (SEPs), and electrically elicited blink reflexes (BRs) to evaluate the brainstem function in 31 patients with meyelomeningocele (MMC) including 22 with Chiari type-II malformation. The I-III interpeak latency (IPL) of the BAEPs and the N9-N13 IPL of the SEPs tended to become gradually prolonged from the normal range with increasing age. The III-V IPL of the BAEPs and the N13-N20 IPL of the SEPs were initially prolonged and decreased progressively to the normal range. These findings indicated a gradual latency shortening of the brainstem components and latency prolongation of the peripheral components. Thus, while primary brainstem dysfunction may improve with age, secondary dysfunction due to stretching and elongation of the lower cranial nerves and cervical nerve roots may intensify. The BRs showed an abnormal R2 in 90% of the cases, disclosing subclinical lesions in the medulla oblongata which were not detected by BAEPs alone. BAEPs, SEPs and BRs were combined to yield a functional evaluation of the brainstem and lower cranial nerves that could not be done by magnetic resonance imaging alone. No close relation was found between electrophysiological abnormalities and the degree of hindbrain anomaly by neuroimaging.
PMID: 7786804
Somatosensory evoked potentials to median nerve stimulation in meningomyelocele
Nishimura T, Mori K. Somatosensory evoked potentials to median nerve stimulation in meningomyelocele: what is occurring in the hindbrain and its connections during growth? Childs Nervous System. 1996 Jan;12(1):13-26. Review.
Twenty patients with meningomyelocele (MMC) and shunted hydrocephalus, ranging in age from 3 to 23 years old, underwent serial recording of short-latency somatosensory evoked potentials (SEPs) to median nerve stimulation, on the basis of which to assess the evolution of dysfunction in the brainstem and its connections (cervical spinal cord, cervical nerve roots, lower cranial nerves). Eighteen patients had Chiari type II malformations, none of which was symptomatic. In all 20 patients, serial SEP recordings were obtained repeatedly after periods ranging from 2 to 7 years. The results were as follows: (1) the ratio of EP-N13 interpeak latencies (IPLs) to body height (BH) tended to lengthen gradually after starting in the normal range with growth. (2) In contrast, the ratio N13-N20 IPLs/BH decreased continuously to the normal range with growth, after initial prolongation. These findings and our earlier studies of brainstem auditory evoked potentials suggest that compression and traction result in strangulation of the cervical spinal cord and kinked medulla as well as stretching of the cervical nerve roots and lower cranial nerves. However, primary intrinsic functional disorders of the brainstem appeared to improve gradually during growth. The natural history of Chiari type II malformations involves these opposing dynamic phenomena in the hindbrain and its connections.
PMID: 8869170
Twenty patients with meningomyelocele (MMC) and shunted hydrocephalus, ranging in age from 3 to 23 years old, underwent serial recording of short-latency somatosensory evoked potentials (SEPs) to median nerve stimulation, on the basis of which to assess the evolution of dysfunction in the brainstem and its connections (cervical spinal cord, cervical nerve roots, lower cranial nerves). Eighteen patients had Chiari type II malformations, none of which was symptomatic. In all 20 patients, serial SEP recordings were obtained repeatedly after periods ranging from 2 to 7 years. The results were as follows: (1) the ratio of EP-N13 interpeak latencies (IPLs) to body height (BH) tended to lengthen gradually after starting in the normal range with growth. (2) In contrast, the ratio N13-N20 IPLs/BH decreased continuously to the normal range with growth, after initial prolongation. These findings and our earlier studies of brainstem auditory evoked potentials suggest that compression and traction result in strangulation of the cervical spinal cord and kinked medulla as well as stretching of the cervical nerve roots and lower cranial nerves. However, primary intrinsic functional disorders of the brainstem appeared to improve gradually during growth. The natural history of Chiari type II malformations involves these opposing dynamic phenomena in the hindbrain and its connections.
PMID: 8869170
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