Ann Otol 87 :1978
DELAYED ENDOLYMPHATIC HYDROPS HAROLD
F.
SCHUKNECHT,
MD
BOSTON, MASSACHUSETTS
Delayed endolymphatic hydrops is a disease entity that can be differentiated from Meniere's disease. Typically it occurs in patients who have sustained a profound hearing loss in one ear, usually from infection or trauma, and then after a prolonged period of time develop either episodic vertigo from the same ear (ipsilateral delayed endolymphatic hydrops) or fluctuating hearing loss, also sometimes with episodic vertigo, in the opposite ear (contralateral delayed endolymphatic hydrops). The ipsilateral form of the disease may be treated by labyrinthectomy but no satisfactory therapy is available for the contralateral form of the disease.
The purpose of this paper is to desscribe the clinical manifestations of delayed endolymphatic hydrops, an entity which can be differentiated from Meniere's disease. The ipsilateral type of this disorder was described by Nadal et all and by Wolfson and Leiberrnan" in almost simultaneous publications. It is characterized by the delayed onset of episodic vertigo of the Meniere's type caused by ears having preexisting profound hearing losses. Meniere's type vertigo may be defined as attacks of spinning type vertigo of sudden onset and prolonged duration (one or more hours), and of sufficient severity to cause nausea and vomiting. Most patients with this disorder retain normal hearing and vestibular function in their opposite ears, however it may also occur in patients with bilateral profound hearing losses. The contralateral type of delayed endolymphatic hydrops also occurs in patients who have had a profound unilateral hearing loss, but differs from the ipsilateral type in that they subsequently develop fluctuating hearing loss in the opposite ear, also occasionally with vertigo. IPSILATERAL HYDROPS
DELAYED
ENDOLYMPHATIC
Twelve patients have been encountered who satisfy the criteria for the ipsilateral delayed hydrops syndrome
(Table 1). Seven of these were previously reported by Nadal et al.' The criteria for inclusion in the group are: 1) profound hearing loss in one or both ears discovered incidentally in childhood or related to some specific disease or trauma, and 2) subsequent onset of episodic vertigo of the Meniere's type. Hearing losses were unilateral in ten and bilateral in two and equally distributed between right and left ears. The hearing losses were discovered incidentally in childhood in six, and were believed to be caused by head trauma in two, viral labyrinthitis or upper respiratory infection in two, mumps in one and influenza in one. Table 2 shows a tabulation of alleged causes of unilateral deafness in the cases reported to date. The time span from the discovery of deafness to the onset of episodic vertigo was one year for the patient having mumps and two years for one of the patients in which the etiology of the hydrops was head blow. Although the head blows were severe there was no clear history of skull fracture and it is not known whether radiologic studies were done. In the remaining ten patients the time spans ranged from 11 to 45 years with an average of 26.8 years. Two of the patients had spontaneous subsidence of episodic vertigo, one after four years and another after one year
From the Harvard Medical School and the Massachusetts Eye and Ear Infirmary. Boston, Massachusetts. Presented at the meeting of the American Otological Society, Inc., Palm Beach Florida April 23-24. 1978. ' ,
743
Downloaded from aor.sagepub.com at UNIV OF NEW HAMPSHIRE on February 18, 2015
HAROLD F. SCHUKNECHT
744
TABLE 1. IPSILATERAL DELAYED ENDOLYMPHATIC HYDROPS Early History Profound Hearing Loss
1 2 3 4 5 6 7 8 9 10 11 12
CEo LP CWo RDo JC A La A Lo o McN° FS CD o RM VVo
L R L L R R R L R L Bilat. Bilat.
Late History
Age
Onset of Episodic Vertigo
+ + + + + + + + + + + +
6 - mumps 9 - flu 8 - trauma 4 - trauma Childhood Childhood Childhood Childhood Childhood Childhood Childhood Childhood
At Age
Caloric Responses Right Left
7 53 10 27 18 16-20 42 25 25-26 32 33 48
N DVR N N N DVR 0 N DVR N DVR 0
Labyrinthectomy Age Year
N N DVR N N N N DVR N DVR N N
1966-L
10
1970-R 1973-L 1976-R
22 27 21
1966-R 1970-L
42 28
1964-L
34
1973-R
51
'Previously reported by Nadol et al. DVR - Decreased vestibular response. R - Right; L - Left; N - Normal.
of symptoms. At the time of the original examination, the remaining ten had experienced episodic vertigo for periods of time ranging from less than 1 year to 14 years with an average of about 3)~ years. Caloric tests were performed by the Kobrak minimal technique using 5 cc of water at 26.6 C and, if no response occurred, with 5 cc of ice water. By this method the responses were judged to be normal in the opposite ears of all ten patients with unilateral hearing loss. The deaf ears in this group showed normal responses in three, decreased vestibular responses in six, and no response
in one. The fistula test was performed on two of them and was positive (Hennebert's sign) 3 in the deaf ear in one. Most of the patients also had a full battery of vestibular tests with ENG recording but this generally added little to the information acquired by the method described above. Serological tests for syphilis were performed on two patients and both were nonreactive. Radiologic studies of the temporal bones were done on seven patients, all of which were normal. Labyrinthectomy was performed in the deaf ear of seven patients with unilateral hearing loss and in one ear of a
TABLE 2. ALLEGED CAUSES OF PRIOR HEARING LOSSES IN PATIENTS WITH DELAYED HYDROPS Nadol et al
Wolfson and Leiberman
[psilateral
I psilateral
t psilateral
2
4 (2) (2) (2) (1)
Early childhood, causes unknown Head trauma Viral labyrinthitis URI Mumps Mastoiditis and labyrinthitis Influenza Meningitis Diphtheria Total
2 3 3
2
1 2
Schuknecht Contralateral
5
1 1 1 1 12
5
5
() Previously reported by Nadal et al.
Downloaded from aor.sagepub.com at UNIV OF NEW HAMPSHIRE on February 18, 2015
6
Total
13 3 4 4 1 1 1 1 28
745
DELAYED ENDOLYMPHATIC HYDROPS 12~
2!lO
!lOO
0 10
....
--.r
20 30
IK
2K
4K
8K
16K 0
-----
10 20
R-O
DISCRIM L -100 S
30 40
40 ~O
60 70 80 90 100 110
I I I I f ~
JC 2-3-76
~O
60 70 80 90 100 110
Fig. 1. (Case JC) Audiogram at age 21. He was found to have a profound right hearing loss at the age of six. Vertigo was first experienced at the age of 18.
patient with bilateral hearing loss. This ear was chosen on the basis of a positive Hennebert's sign and absent caloric response to ice water. Postoperatively he had vertigo and nystagmus for several weeks and unsteadiness for two years after which he had no further complaints of vertigo. The method employed was the trans tympanic route through the oval window with removal of the utricle and saccule and maceration of the cristae.' No perilymph gushers were encountered. A classical example of ipsilateral delayed endolymphatic hydrops is the following case: Case [C. At age six, the patient noticed that he could not hear in the right ear. He did not know how long the loss had existed. There had been no illnesses or traumas which could be related to the hearing loss. He was healthy without other symptoms of otological disease until the age of 18 when he felt slightly unsteady for a few days. Six months later he began having episodic vertigo with associated
nausea and vomiting. During the next six months, he had five severe attacks and an almost constant sensation of unsteadiness. At the age of 20, he stated that he was somewhat disabled by the unsteadiness but the attacks of vertigo were less severe. At that time, audiometry revealed profound hearing loss on the right and normal hearing on the left. ENG showed a left directional preponderance. Polytornographic radiological studies of the temporal bones were normal. He was advised that a right labyrinthectomy would probably relieve his vertigo, but he declined to have surgery. At the age of 21, he continued to complain of unsteadiness and occasional episodes of vertigo but he had no nausea or vomiting. He noticed that changes in altitude and digital pressure on his right ear caused momentary vertigo. Examination revealed a positive Hennebert's sign on the right ear. Audiometry again showed a profound hearing loss in the right and normal hearing on the left (Fig. 1). He submitted to a right labyrinthectomy. The operation was performed by the transtympanic route. After removal of the incus and stapes, the utricle and saccule were removed through the oval window and the ampulated ends of the semicircular canals were probed with a 3 rnm hook. Postoperatively he experienced severe vertigo and had spontaneous nystagmus to the left. Over a period of several weeks the vertigo improved steadily. Two years later (age 23), he still had slight unsteadiness with quick head movements but no further episodes of episodic vertigo. He had no further symptoms of vertigo with altitude changes or on digital pressure on the ear, and the fistula test was negative. There continued to be a fine spontaneous nystagmus to the left. Ice water caloric test gave no responses on the right. Hearing and caloric responses were normal on the left. Polytomographic radiologic studies were normal. CONTRALATERAL DELAYED ENDOLYMPHATIC HYDROPS
Six patients have been encountered who meet the criteria for contralateral delayed endolymphatic hydrops (Table 3). The criteria for inclusion in this
TABLE 3. CONTRALATERAL DELAYED ENDOLYMPHAT1C HYDROPS Late History Fluetuating EpiProfound Hearing sadie Caloric Responses Hearing Age Age Right Left Loss Loss Vertigo Childhood 14 DVR DVR DR L + + 0 DVR Childhood 10 KL L + + Childhood 30 0 DVR 0 SP R + 0 Childhood 18 0 0 DB L + Childhood 21 R 0 0 0 DP + 0 0 15 49 0 AY R + DVR - Decreased vestibular response; R - Right; L - Left. Early History
1 2 3 4 5 6
Downloaded from aor.sagepub.com at UNIV OF NEW HAMPSHIRE on February 18, 2015
Therapies Steroid Steroid Miscel. med. Miscel. med. Miscel. med. Steroid
HAROLD F. SCHUKNECHT
746 12S 250
SOO
IK
2K
4K
8K
16K
1----------------j0 10 20 30 40 SO
60 70 80 '0 1I-1!J~7~
90
2.2-27-76 3.6-17-76 4.7-22-76
100
S.Il·'5~76
110
Fig. 2. (Case DB) Patient was found to have a profound left hearing loss at the age of four. At the age of 17 he began having fluctuations of hearing in his right ear. The graph shows pure tone thresholds on five tests over a span of one year (age 17 to 18).
group are: 1) profound hearing loss in one ear, discovered incidentally in childhood or related to some specific disease or trauma and 2) subsequent onset in the opposite ear of fluctuating hearing loss, with or without episodic vertigo of the Meniere's type. The profound unilateral sensorineural hearing losses were discovered incidentally in childhood in five and following meningitis at the age of 15 in one. The losses were distributed equally between right and left ears. The time spans from the discovery of unilateral profound hearing loss to the subsequent onset of contralateral fluctuating hearing loss varied from 5 to 34 years for an average of 17 years. Two of the six patients experienced episodic vertigo along with the contralateral fluctuating hearing losses. It is possible that these two cases represent classical Meniere's disease (idiopathic endolymphatic hydrops) occurring incidentally in their contralateral ears, however their young ages at the time of onset (10 and 14 years) would be unusual for Meniere's disease. Four patients in this group experienced no vertigo at any time. Three of them had no response to ice water caloric test in either ear. One had a slight response to ice water in the previously deaf ear but no response in the contralateral ear. The fistula test was performed on
two patients and was positive (Hennebert's sign) in the deaf ear of one. Serological tests for syphilis were nonreactive in all six patients. Radiologic studies of the temporal bones were performed on five patients, all of which were normal. All six patients received a variety of medical therapies including low salt diet, nicotinic acid, meclizene, and histamine injections, and three had one or more courses of steroid therapy. None have shown a clear response to therapy. The following case history is representative of this group: Case DB. This patient had congenital idiopathic thrombocytopenic purpura in infancy for which he received multiple transfusions. At about the age of four it was discovered that he had no hearing in his left ear. He was noted to be a clumsy child with poor motor coordination. At the age of 17, he noticed the onset of intermittent tinnitus and hearing loss in his right ear. He had no vertigo. He was treated with a variety of medications including dexamethasone, diazepam, chlorpheniramine, intravenous histamine, low salt diet, and steroids. The VDRL and FTA serologic tests were negative, lipid profile was normal, glucose tolerance test was normal, and urine and blood analyses were normal. The glycerol test was positive with the speech reception levels improving from 48 to 28 dB in one hour and dropping to 36 dB in four hours. His history was negative for otalgia, otorrhea, noise exposure, head injury, meningitis, thyroid and kidney disease, and severe systemic infections. There was no family history of hearing loss. He had had chicken pox and measles but not mumps. During the following year his hearing losses fluctuated from near normal to 60 dB (Fig. 2). The pure tone threshold patterns were flat and Bekesy tracing was type II. Speech discrimination varied from 98% to 84% 125
250
sco
21
DELAYED ENDOLYMPHATIC HYDROPS HAROLD
F.
SCHUKNECHT,
MD
BOSTON, MASSACHUSETTS
Delayed endolymphatic hydrops is a disease entity that can be differentiated from Meniere's disease. Typically it occurs in patients who have sustained a profound hearing loss in one ear, usually from infection or trauma, and then after a prolonged period of time develop either episodic vertigo from the same ear (ipsilateral delayed endolymphatic hydrops) or fluctuating hearing loss, also sometimes with episodic vertigo, in the opposite ear (contralateral delayed endolymphatic hydrops). The ipsilateral form of the disease may be treated by labyrinthectomy but no satisfactory therapy is available for the contralateral form of the disease.
The purpose of this paper is to desscribe the clinical manifestations of delayed endolymphatic hydrops, an entity which can be differentiated from Meniere's disease. The ipsilateral type of this disorder was described by Nadal et all and by Wolfson and Leiberrnan" in almost simultaneous publications. It is characterized by the delayed onset of episodic vertigo of the Meniere's type caused by ears having preexisting profound hearing losses. Meniere's type vertigo may be defined as attacks of spinning type vertigo of sudden onset and prolonged duration (one or more hours), and of sufficient severity to cause nausea and vomiting. Most patients with this disorder retain normal hearing and vestibular function in their opposite ears, however it may also occur in patients with bilateral profound hearing losses. The contralateral type of delayed endolymphatic hydrops also occurs in patients who have had a profound unilateral hearing loss, but differs from the ipsilateral type in that they subsequently develop fluctuating hearing loss in the opposite ear, also occasionally with vertigo. IPSILATERAL HYDROPS
DELAYED
ENDOLYMPHATIC
Twelve patients have been encountered who satisfy the criteria for the ipsilateral delayed hydrops syndrome
(Table 1). Seven of these were previously reported by Nadal et al.' The criteria for inclusion in the group are: 1) profound hearing loss in one or both ears discovered incidentally in childhood or related to some specific disease or trauma, and 2) subsequent onset of episodic vertigo of the Meniere's type. Hearing losses were unilateral in ten and bilateral in two and equally distributed between right and left ears. The hearing losses were discovered incidentally in childhood in six, and were believed to be caused by head trauma in two, viral labyrinthitis or upper respiratory infection in two, mumps in one and influenza in one. Table 2 shows a tabulation of alleged causes of unilateral deafness in the cases reported to date. The time span from the discovery of deafness to the onset of episodic vertigo was one year for the patient having mumps and two years for one of the patients in which the etiology of the hydrops was head blow. Although the head blows were severe there was no clear history of skull fracture and it is not known whether radiologic studies were done. In the remaining ten patients the time spans ranged from 11 to 45 years with an average of 26.8 years. Two of the patients had spontaneous subsidence of episodic vertigo, one after four years and another after one year
From the Harvard Medical School and the Massachusetts Eye and Ear Infirmary. Boston, Massachusetts. Presented at the meeting of the American Otological Society, Inc., Palm Beach Florida April 23-24. 1978. ' ,
743
Downloaded from aor.sagepub.com at UNIV OF NEW HAMPSHIRE on February 18, 2015
HAROLD F. SCHUKNECHT
744
TABLE 1. IPSILATERAL DELAYED ENDOLYMPHATIC HYDROPS Early History Profound Hearing Loss
1 2 3 4 5 6 7 8 9 10 11 12
CEo LP CWo RDo JC A La A Lo o McN° FS CD o RM VVo
L R L L R R R L R L Bilat. Bilat.
Late History
Age
Onset of Episodic Vertigo
+ + + + + + + + + + + +
6 - mumps 9 - flu 8 - trauma 4 - trauma Childhood Childhood Childhood Childhood Childhood Childhood Childhood Childhood
At Age
Caloric Responses Right Left
7 53 10 27 18 16-20 42 25 25-26 32 33 48
N DVR N N N DVR 0 N DVR N DVR 0
Labyrinthectomy Age Year
N N DVR N N N N DVR N DVR N N
1966-L
10
1970-R 1973-L 1976-R
22 27 21
1966-R 1970-L
42 28
1964-L
34
1973-R
51
'Previously reported by Nadol et al. DVR - Decreased vestibular response. R - Right; L - Left; N - Normal.
of symptoms. At the time of the original examination, the remaining ten had experienced episodic vertigo for periods of time ranging from less than 1 year to 14 years with an average of about 3)~ years. Caloric tests were performed by the Kobrak minimal technique using 5 cc of water at 26.6 C and, if no response occurred, with 5 cc of ice water. By this method the responses were judged to be normal in the opposite ears of all ten patients with unilateral hearing loss. The deaf ears in this group showed normal responses in three, decreased vestibular responses in six, and no response
in one. The fistula test was performed on two of them and was positive (Hennebert's sign) 3 in the deaf ear in one. Most of the patients also had a full battery of vestibular tests with ENG recording but this generally added little to the information acquired by the method described above. Serological tests for syphilis were performed on two patients and both were nonreactive. Radiologic studies of the temporal bones were done on seven patients, all of which were normal. Labyrinthectomy was performed in the deaf ear of seven patients with unilateral hearing loss and in one ear of a
TABLE 2. ALLEGED CAUSES OF PRIOR HEARING LOSSES IN PATIENTS WITH DELAYED HYDROPS Nadol et al
Wolfson and Leiberman
[psilateral
I psilateral
t psilateral
2
4 (2) (2) (2) (1)
Early childhood, causes unknown Head trauma Viral labyrinthitis URI Mumps Mastoiditis and labyrinthitis Influenza Meningitis Diphtheria Total
2 3 3
2
1 2
Schuknecht Contralateral
5
1 1 1 1 12
5
5
() Previously reported by Nadal et al.
Downloaded from aor.sagepub.com at UNIV OF NEW HAMPSHIRE on February 18, 2015
6
Total
13 3 4 4 1 1 1 1 28
745
DELAYED ENDOLYMPHATIC HYDROPS 12~
2!lO
!lOO
0 10
....
--.r
20 30
IK
2K
4K
8K
16K 0
-----
10 20
R-O
DISCRIM L -100 S
30 40
40 ~O
60 70 80 90 100 110
I I I I f ~
JC 2-3-76
~O
60 70 80 90 100 110
Fig. 1. (Case JC) Audiogram at age 21. He was found to have a profound right hearing loss at the age of six. Vertigo was first experienced at the age of 18.
patient with bilateral hearing loss. This ear was chosen on the basis of a positive Hennebert's sign and absent caloric response to ice water. Postoperatively he had vertigo and nystagmus for several weeks and unsteadiness for two years after which he had no further complaints of vertigo. The method employed was the trans tympanic route through the oval window with removal of the utricle and saccule and maceration of the cristae.' No perilymph gushers were encountered. A classical example of ipsilateral delayed endolymphatic hydrops is the following case: Case [C. At age six, the patient noticed that he could not hear in the right ear. He did not know how long the loss had existed. There had been no illnesses or traumas which could be related to the hearing loss. He was healthy without other symptoms of otological disease until the age of 18 when he felt slightly unsteady for a few days. Six months later he began having episodic vertigo with associated
nausea and vomiting. During the next six months, he had five severe attacks and an almost constant sensation of unsteadiness. At the age of 20, he stated that he was somewhat disabled by the unsteadiness but the attacks of vertigo were less severe. At that time, audiometry revealed profound hearing loss on the right and normal hearing on the left. ENG showed a left directional preponderance. Polytornographic radiological studies of the temporal bones were normal. He was advised that a right labyrinthectomy would probably relieve his vertigo, but he declined to have surgery. At the age of 21, he continued to complain of unsteadiness and occasional episodes of vertigo but he had no nausea or vomiting. He noticed that changes in altitude and digital pressure on his right ear caused momentary vertigo. Examination revealed a positive Hennebert's sign on the right ear. Audiometry again showed a profound hearing loss in the right and normal hearing on the left (Fig. 1). He submitted to a right labyrinthectomy. The operation was performed by the transtympanic route. After removal of the incus and stapes, the utricle and saccule were removed through the oval window and the ampulated ends of the semicircular canals were probed with a 3 rnm hook. Postoperatively he experienced severe vertigo and had spontaneous nystagmus to the left. Over a period of several weeks the vertigo improved steadily. Two years later (age 23), he still had slight unsteadiness with quick head movements but no further episodes of episodic vertigo. He had no further symptoms of vertigo with altitude changes or on digital pressure on the ear, and the fistula test was negative. There continued to be a fine spontaneous nystagmus to the left. Ice water caloric test gave no responses on the right. Hearing and caloric responses were normal on the left. Polytomographic radiologic studies were normal. CONTRALATERAL DELAYED ENDOLYMPHATIC HYDROPS
Six patients have been encountered who meet the criteria for contralateral delayed endolymphatic hydrops (Table 3). The criteria for inclusion in this
TABLE 3. CONTRALATERAL DELAYED ENDOLYMPHAT1C HYDROPS Late History Fluetuating EpiProfound Hearing sadie Caloric Responses Hearing Age Age Right Left Loss Loss Vertigo Childhood 14 DVR DVR DR L + + 0 DVR Childhood 10 KL L + + Childhood 30 0 DVR 0 SP R + 0 Childhood 18 0 0 DB L + Childhood 21 R 0 0 0 DP + 0 0 15 49 0 AY R + DVR - Decreased vestibular response; R - Right; L - Left. Early History
1 2 3 4 5 6
Downloaded from aor.sagepub.com at UNIV OF NEW HAMPSHIRE on February 18, 2015
Therapies Steroid Steroid Miscel. med. Miscel. med. Miscel. med. Steroid
HAROLD F. SCHUKNECHT
746 12S 250
SOO
IK
2K
4K
8K
16K
1----------------j0 10 20 30 40 SO
60 70 80 '0 1I-1!J~7~
90
2.2-27-76 3.6-17-76 4.7-22-76
100
S.Il·'5~76
110
Fig. 2. (Case DB) Patient was found to have a profound left hearing loss at the age of four. At the age of 17 he began having fluctuations of hearing in his right ear. The graph shows pure tone thresholds on five tests over a span of one year (age 17 to 18).
group are: 1) profound hearing loss in one ear, discovered incidentally in childhood or related to some specific disease or trauma and 2) subsequent onset in the opposite ear of fluctuating hearing loss, with or without episodic vertigo of the Meniere's type. The profound unilateral sensorineural hearing losses were discovered incidentally in childhood in five and following meningitis at the age of 15 in one. The losses were distributed equally between right and left ears. The time spans from the discovery of unilateral profound hearing loss to the subsequent onset of contralateral fluctuating hearing loss varied from 5 to 34 years for an average of 17 years. Two of the six patients experienced episodic vertigo along with the contralateral fluctuating hearing losses. It is possible that these two cases represent classical Meniere's disease (idiopathic endolymphatic hydrops) occurring incidentally in their contralateral ears, however their young ages at the time of onset (10 and 14 years) would be unusual for Meniere's disease. Four patients in this group experienced no vertigo at any time. Three of them had no response to ice water caloric test in either ear. One had a slight response to ice water in the previously deaf ear but no response in the contralateral ear. The fistula test was performed on
two patients and was positive (Hennebert's sign) in the deaf ear of one. Serological tests for syphilis were nonreactive in all six patients. Radiologic studies of the temporal bones were performed on five patients, all of which were normal. All six patients received a variety of medical therapies including low salt diet, nicotinic acid, meclizene, and histamine injections, and three had one or more courses of steroid therapy. None have shown a clear response to therapy. The following case history is representative of this group: Case DB. This patient had congenital idiopathic thrombocytopenic purpura in infancy for which he received multiple transfusions. At about the age of four it was discovered that he had no hearing in his left ear. He was noted to be a clumsy child with poor motor coordination. At the age of 17, he noticed the onset of intermittent tinnitus and hearing loss in his right ear. He had no vertigo. He was treated with a variety of medications including dexamethasone, diazepam, chlorpheniramine, intravenous histamine, low salt diet, and steroids. The VDRL and FTA serologic tests were negative, lipid profile was normal, glucose tolerance test was normal, and urine and blood analyses were normal. The glycerol test was positive with the speech reception levels improving from 48 to 28 dB in one hour and dropping to 36 dB in four hours. His history was negative for otalgia, otorrhea, noise exposure, head injury, meningitis, thyroid and kidney disease, and severe systemic infections. There was no family history of hearing loss. He had had chicken pox and measles but not mumps. During the following year his hearing losses fluctuated from near normal to 60 dB (Fig. 2). The pure tone threshold patterns were flat and Bekesy tracing was type II. Speech discrimination varied from 98% to 84% 125
250
sco
21
