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BRIEF COMMUNICATIONS: Chun-Liang Pan, Meng-Fai Kuo, and Sung-Tsang Hsieh Auditory agnosia caused by a tectal germinoma Neurology 2004; 63: 2387-2389 [Abstract] [Full text] [PDF]

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Auditory agnosia caused by a tectal germinoma

Eileen Nicole Simon, PhD, RN   (8 March 2005)

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Sung-Tsang Hsieh, Chun-Liang Pan   (8 March 2005)

Auditory agnosia caused by a tectal germinoma 8 March 2005
Eileen Nicole Simon, PhD, RN, conradsimon.org 11 Hayes Avenue, Lexington MA 02420-3521 Send Correspondence to journal: Re: Auditory agnosia caused by a tectal germinoma eileen4brainresearch{at}yahoo.com Eileen Nicole Simon, PhD, RN	The report by Pan et al [1] and the five earlier reports they cite highlight the importance of subcortical processing of acoustic data for understanding of spoken language. The inferior colliculus was the primary site of injury in each report, and all of the patients had normal comprehension of spoken language before their affliction. The inferior colliculus was prominently damaged in experiments with monkeys subjected to asphyxia at birth. [2, 3] The importance of this finding has gone unrecognized because it was a surprise discovery during an attempt to create an animal model of cerebral palsy. Myers claimed that ischemic brainstem injury (most severe in the inferior colliculi) bore no relationship to brain pathology observed in human infants. [3] Windle proposed that brainstem impairments might underlie what was then referred to as "minimal cerebral dysfunction" or MCD. [2] Developmental language disorder is the most serious aspect of what is now known as pervasive developmental disorder (PDD). Involvement of the inferior colliculi as part of a brainstem pattern of damage in human infants can be found in at least eight case reports. [4] Natsume et al. also cited references in which the greatest blood flow and highest rate of aerobic metabolism in the brain were measured in the inferior colliculi. High metabolic activity in this small area of the brain can now be seen in fMRI scans [5]. The importance of the data from the mostly long-forgotten investigations of experimental asphyxia in newborn monkeys merits reconsideration. Ischemic brainstem injury at birth can be viewed as a variant of Wernicke's encephalopathy. MRI technology might be employed to focus on involvement of the inferior colliculi in developmental language disorders in the same way it is used to examine pathology involving the quadrigeminal plate in alcoholism. References [1] Pan CL, Kuo MF, Hsieh ST. Auditory agnosia caused by a tectal germinoma. Neurology. 2004 Dec 28;63(12):2387-9. [2] Windle WF. Brain damage by asphyxia at birth. Sci Am. 1969 Oct;221(4):76-84. [3] Myers RE. Two patterns of brain damage and their conditions of occurrence. Am J Obstet Gynecol 1972; 112:246-76. [4] Natsume J, Watanabe K, Kuno K, Hayakawa F, Hashizume Y. Clinical, neurophysiologic, and neuropathological features of an infant with brain damage of total asphyxia type (Myers). Pediatr Neurol. 1995 Jul;13(1):61- 4. [5] Budd TW, Hall DA, Goncalves MS, Akeroyd MA, Foster JR, Palmer AR, Head K, Summerfield AQ. Binaural specialisation in human auditory cortex: an fMRI investigation of interaural correlation sensitivity. Neuroimage. 2003 Nov;20(3):1783-94. No conflicts of interest to declare.
Reply to Simon 8 March 2005
Sung-Tsang Hsieh, Department of Anatomy and Cell biology, National Taiwan University College of Medicine; 1 Jen-Ai Road, Sec. 1, Taipei 10018, Taiwan, Chun-Liang Pan Send Correspondence to journal: Re: Reply to Simon shsieh{at}ntu.edu.tw Sung-Tsang Hsieh, et al.	We appreciate the interest of Dr. Simon in our report on auditory agnosia caused by a tumor in the inferior colliculi (IC). [1] She proposed an intriguing hypothesis that IC is one of the primary sites of pathology in language disorders accompanying certain developmental neurological diseases, such as pervasive developmental disorders or cerebral palsy, based on evidence from clinical observations and primate models of ischemic brain injury. [2,3] Despite the apparent differences between developmental language disorders and hearing disorders that occur after language acquisition is complete, IC is implicated in both situations. Unlike the latter, where the impact of IC lesion is more direct, the role of IC in language development remains unclear. One established function of IC is to resolve the frequency components of complex sound spectra, with speech as the most representative and sophisticated substrate. [4] This raises the question whether IC plays an important role in the development of language, probably by functioning as the first auditory integrator as well as the feedback rectifier for speech. Previous studies on structural abnormalities in pervasive developmental disorders were hampered by inadequate anatomical resolution of conventional imaging tools. Functional disturbances without obvious anatomical changes are likely to be overlooked in some of these conditions. With the advance of neuroimaging techniques, particularly the magnetic resonance imaging, these hypotheses are ready to be tested. References 1. Pan CL, Kuo MF, Hsieh ST. Auditory agnosia caused by a tectal germinoma. Neurology 2004; 63: 2387-9. 2. Windle WF. Brain damage by asphyxia at birth. Sci Am 1969; 221: 76-84. 3. Natsume J, Watanabe K, Kuno K, Hayakawa F, Hashizume Y. Clinical, neurophysiologic, and neuropathological features of an infant with brain damage of total asphyxia type (Myers). Pediatr Neurol 1995; 13: 61- 4. 4. Ehret G, Merzenich MM. Auditory midbrain responses parallel spectral integration phenomena. Science 1985; 227: 1245-7. The authors declare no conflicts of interest.