Journal of Neuro-Ophthalmology, June 1986, Volume 6, Issue 2

Central stem deafness of brunner.

Journal o{Clinical Nellro·(II'I1II",/nll1i<>xy 6(21: 133-1.16.1986. Editorial Comment Central Stem Deafness of Brunner c,) 1986 Raven Press. New York In this issue of the JournaL a most unusual case is reported by Toshniwal et al. which brought to mind the words of prophet Isaiah (6:9): "And he said, Go, and tell this people, Hear ye indeed, but understand not; and see ye indeed, but perceive not." Everyone can recall instances where we have seen, but not perceived, and have heard, but did not truly understand. Years ago, Dr. Frank B. Walsh and Dr. David Clark presented a patient at Hopkins to Sir Francis Walshe and asked the famous neurologist, "Sir Francis, have you ever seen a case of Kinnier Wilson's ectopic pupil sign in a pinealoma?" Sir Francis replied, " I have seen this several times before, but this is the first time I have ever perceived it." However, Toshniwal and associates provide us with an even more basic sit­uation, in which an 8-year-old previously healthy girl began to develop progressive hearing loss over a 4-month period, and within 1 month became totally deaf in both ears. The patient was alert and cooperative, but showed bilateral papill­edema, abnormal vertical eye movements, and a gait disturbance; after appropriate neuroradiologic study, she was found to have a mass lesion com­pressing the dorsal midbrain. Subsequently, this was proven histologically to be a pinealoblastoma. The patient was treated appropriately and the ab­normal eye movements vanished; however, the patient was left with the hearing loss. This paper was submitted to this journal with emphasis on the eye movements which were called "ocular dipping." The authors stated with regard to the deafness, "Though described with other brain­stem neurological disorders, as well as a false lo­calizing sign with raised intracranial pressure, this symptom remains distinctly unusual and has not been described with pinealoma." Now, please bear with me, gentle reader, be­cause I think that if you do, you will appreciate the behind-the-scenes communications that transpire between editorial board members, and that these will, in this particular case, only serve to heighten your interest, perhaps even to fever pitch. The ar­ticle was submitted to two noted reviewers who were unhappy with the comments about the eye movements. One stated, "The eye movement ex- /33 aminations were cursory and not quantified. There is a long discursive confusing discussion about the control of vertical gaze which has little to do with the case and will be incomprehensible to most readers. The materials on hearing loss was interesting but no vestibular function tests were performed." Another reviewer commented, "Their clinical eye movement description is too brief and recordings are not available. As re­ported, the patient appears to have the rather common pretectal sign of downgaze preference requiring voluntary efforts to maintain horizontal gaze. Upgaze effort is the presumptive cause of pretectallid retraction and is usually accompanied by difficulty in full voluntary elevation of the eyes. A specific comment about the absence of retrac­tion and the ease of full upward saccades would be helpful. ... I'm not sure it's helpful to single out individual voluntary refixations and equate them with ocular dipping. To diagnose dipping in an awake patient probably stretches that term beyond any practical usefulness." This reviewer then began to wax eloquent and added, "The patient's deafness, also described in insufficient detail, is unusual and potentially more interesting-if the etiology can be established. The obvious localization to the inferior colliculus fails to account for auditory-evoked potential wave I absence, and the authors' speculations about co­chlear damage aren't very convincing. While there are indeed several studies that purport to show moderate hearing loss with increased intracranial pressure, isolated increase in benign intracranial hypertension does not cause symptomatic hearing loss, transient plateau waves and venous hum masking aside." Now while all this was going on, one day an outstanding neuroradiologist walked through my office and saw Toshniwal's Fig. 2 on my desk. When told that this was an 8-year-old totally deaf girl, he replied, "What a beautiful picture-note that the tumor is pushing right on the inferior col­liculi- I'll bet that's why she's deaf!" The pathogenesis of the deafness in this little girl then really began to eat into my brain! The paper was then submitted to one of the world's 134 J. L. SMITH most renowned senior neuro-ophthalmologists for another opinion. After again commenting on the discussion on the eye movements that "much of the discussion with brainstem centers for gaze that are related to the present case only with an over­dose of speculation," then came the bombshell! "The deafness is presumably attributable to the increased intracranial pressure and does not war­rant further discussion. I am not familiar with the syndrome which you refer to as Blummer's" [ac­tually I should have called it Brunner's], "but I do not recall deafness with any of the many cases of pinealomas which I have seen. Moreover, if the inferior colliculus is analogous for hearing to what the superior colliculus is for vision, I would be surprised if deafness would result in this area." Now, your editor began to sweat a bit. He re­called reading somewhere about "central stem deaf­ness of Brunner," but could not immediately put his finger on the reference! However, in Dr. Walsh's second edition (the red single volume) on page 1064 in the section on pineal tumors, the statement was made: "Deafness is commonly present, as a result of involvement of the inferior colliculi. High tones are the first to be lost." Beady fingers then reached for the third edition (now Walsh and Hoyt), and on page 2242 the same statement appeared about pineal tumors: "Deaf­ness is commonly present, as a result of involve­ment of the inferior colliculi. High tones are the first to be lost." To my mind, the point about this case that really was of interest was the sudden de­velopment of bilateral total deafness in this young girl. It was obvious from the above communica­tions that the neuro-ophthalmic community of today was not really overwhelmed with informa­tion about that specific point. It was decided then that it would be an appropriate time to call the west coast! Immediately the following came back: "There is absolutely nothing new about collicular deafness. See Arch Psychiatr Nervenkr 1894;26:363­80, and Z Ohrenheilkunde 1896;29:28-91. If you want a recent article, see: Luxon LM. Hearing loss in brainstem disorders. J Neurol Neurosurg Psychi­atry 1980;43:510-5." Further investigation turned up some very inter­esting facts from the literature. Dr. Gilbert Horrax, in Arch Neurol Psychiatry 1927;17(Feb):179, re­viewed 30 autopsied cases of brainstem tumors from Dr. Cushing's records at Hopkins and Peter Bent Brigham Hospitals. Fifteen were tumors orig­inating from the pineal body, and the other 15 tumors were largely or wholly within the pons. On page lBO, Dr. Horrax stated: "Hearing. A second subjective symptom of differential value was the reference to deafness on the part of patients in the I Clill Nl'lIro-ophthalmol. Vol. 6. No.2. 1986 two groups. Eleven of the 30 patients complained of some acoustic difficulty, and rather unex­pectedly this was true of only four in the pineal group, whereas it was recognized by se~en of the 15 patients with pontile lesions. The Important feature was the way in which such difficulties were manifested, because the pineal patients did not refer the trouble to either side, while in the pontile group the acoustic loss was always defi­nitely referred to one ear or the other. This, of course, is what would be expected from a rela­tively symmetrical pressure on the superior col­liculi by a tumor arising from a midline structure (pineal) in the former that might arise at any point in the pons." In a subsequent paper, Posner and Horrax (Eye signs in pineal tumors. J Neurosurg 1946;3:15-24), in discussing the most frequent signs and symptoms from pineal tumors, listed in­creased intracranial pressure and pressure on the corpora quadrigemina as giving rise to eye signs (e.g., impaired pupillary reactions, limitations of extraocular movements, especially conjugate movements upward, nystagmus, strabismus) and central deafness. "This is now believed to be due not entirely to pressure on the inferior colliculi but also to involvement of the lateral lemnisci." One may consider the original cases of Horrax and Cushing as arising from such antiquity that diagnosis was delayed much, much longer than would be the case in more modern days, and that perhaps that explained why pineal tumors pre­sented at times complaining of deafness. How­ever, a paper so tremendously interesting that it prompted this long editorial now must be cited: "Midbrain deafness-tumor of the midbrain pro­ducing sudden and complete deafness," by P. Sloane, A. Persky, and M. Saltzman, in Arch Neurol Psychiatry 1943;49:237-43. In that instance, a 55-year-old man was being followed for im­paired hearing for about 18 months. The patient later developed sudden complete deafness and nystagmoid movements of the eyes, became quite somnolent, and was admitted to hospital. Audi­ometry revealed complete loss of hearing in both ears. Later, pupils became unequal and reacted abnormally. Lumbar puncture revealed a pressure 130 mm of water. Patient deteriorated in hospital but had normal fundi, had no increase of intra­cranial pressure on repeating the spinal tap, and went into coma and died 17 days after admission to hospital. Autopsy showed a neoplasm in the brainstem, but otherwise the brain showed no abnormalities. The tumor extended from the pos­terior part of hypothalamus, infiltrated the mid­brain and pons, with its tail projecting between cerebellar hemispheres. The tumor involved the EDITORIAL: CENTRAL STEM DEAFNESS OF BRUNNER /35 entire tegmentum of midbrain and pons, particu­larly on the left side. The aqueduct was displaced to the right without being blocked, so that it was possible to pass a probe through its entire length. The tumor was histologically an astrocytoma or astroblastoma. The discussion of this paper is really excellent reading. The authors point out the outstanding feature of the case as the sudden onset of deafness in a man who previously had shown mild impairment of hearing. After otogenic causes had been ruled out, it was thought initially to be due to involvement of the acoustic nerve. Fixed pupils, absent knee jerks, and deafness sug­gested tabes, but the results of serologic studies were negative. A lesion of the pons with both trap­ezoid bodies also was suggested, but it was only after he began to show other signs of cerebral in­volvement that the cause of the deafness was sought elsewhere. "As is well known, lesions which produce deafness as a rule involve the eighth nerve or its terminal filaments. It is less well known, however, that impairment of hearing may occur with lesions of the brainstem. In the pons, for instance, it may result from involvement of the trapezoid bodies. The impairment in cases of such a lesion is more likely to be unilateral and incom­plete, because the size of the pons enables many fibers to escape compression. Horrax, in a study of 15 cases of pontile tumor, found severe bilat­eral impairment in three, unilateral deafness in four, and questionable impairment in one case." In contrast to these observations, Brunner in his monograph (Brunner H. Otologische Diagnostik der Hirntumoren. Berlin: Urban & Schwarzenberg, 1936, chapters 8 and 9) described the syndrome of midbrain deafness in considerable detail and con­cluded that tumors of the tegmentum of the mid­brain are more likely to give rise to sudden and complete deafness. This is because the auditory pathways in this region (namely, lateral lemnisci, inferior colliculi, brachia of posterior quadri­geminate bodies and the medial geniculate bodies) are placed closely together in what has been de­scribed as the "isthmus acusticus." Such lesions usually are associated with descending degenera­tion in the cochlear system down to the spiral nerve of the cochlea. Moreover, the small size of the midbrain and the compactness of its tissues enable a tumor of moderate size to compress the auditory pathways on both sides, as well as to produce widespread functional disorder of other systems. According to Brunner, deafness due to a lesion in the midbrain is usually a late symptom and therefore has an unfavorable prognostic sig­nificance. As a rule, it shows an unusually rapid, almost apoplectiform progression and is asso-ciated with marked shortening of bone conduction and labyrinthine hyperexcitability. He expressed the opinion that the latter change is important in the differential diagnosis of tumors of the mid­brain and those occurring lower in the brainstem or cerebellum. In the latter areas, there is early de­struction of the secondary pathways of the vestib­ular nerves, so that diminished excitability of the labyrinth may be observed before there is any defi­nite impairment of hearing. One-sided lesions give rise to contralateral deafness, since the pathways on each side are connected with the opposite ear. Brunner classified the various condi­tions which give rise to the syndrome as follows: (a) tumors of the tegmentum of the midbrain, caudal to the red nucleus; (b) tumors of the transi­tion zone between the thalamus and the midbrain; (c) pinealomas; (d) suprasellar tumors; and (e) tumors of the quadrigeminate plate." A final paper that should be reviewed is L. M. Luxon's "Hearing loss in brainstem disorders," in J Neurol NeUrOSUrg Psychiatry 1980;43:510-5. This was a review of 309 unselected patients with brainstem disorders; the study was carried out to establish the incidence and degree of hearing loss in the group as a whole, and in each of three sepa­rate groups: patients with multiple sclerosis, ver­tebrobasilar ischemia, or brainstem tumors. Pure tone audiograms were corrected for age and sex; 59% of the patients had hearing thresholds in ex­cess of 10 dB and 26% of patients in excess of 30 dB. The mildest losses were in the multiple scle­rosis group and the most severe in the tumor group. This author stated (p. 514), "Two-thirds of all patients with malignant tumors of the brain stem suffered hearing loss (more than 10 dB) in the present study. Deafness has been reported in association with brainstem tumors, contrary to the views of Liden and Korsan-Bengsten that fatal symptoms supervene before the development of audiological symptoms. Moreover, in the present study 11% of the patients with brainstem malig­nancies complained of deafness, temporarily re­lated to their illness. In about 75% of patients af­fected, the deficit was bilateral, and indeed in 62% of these the deficit was symmetrical. Twenty-five percent of patients with a hearing loss were af­fected unilaterally, suggesting destruction of ipsi­lateral cochlear nuclei or involvement of eighth nerve. Reviewing the distribution of hearing loss, the high frequency levels were most commonly af­fected and indeed the "high tone" loss configura­tion was most commonly seen in bilateral hearing loss. In unilateral deficit, the "island" loss config­uration (again usually affecting the high frequency range) was seen most commonly." I Gill Neuro-ophtllolmol, Vol. 6, No.2, 1986