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Pathology of the auditory system in autosomal trisomies with morphometric and quantitative study of the ventral cochlear nucleus
Journal of the Neurological Scienees, 1981, 51:43 50
43
Elsevier/North-Holland Biomedical Press
P A T H O L O G Y OF T H E A U D I T O R Y SYSTEM 1N A U T O S O M A L TRISOMIES WITH MORPHOMETRIC AND QUANTITATIVE STUDY OF T H E V E N T R A L C O C H L E A R N U C L E U S
ANGELO GANDOLFI, DIKRAN S. HOROUPIAN and RICHARD M. DE TERESA Department Of' Pathology (Neuropathology), The Saul R. Korey Department of" Neurology (Pediatric Neurology) and The Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College qf Medicine, Bronx, N Y 10461 (U.S.A.)
(Received 20 October, 1980) (Accepted 3 December, 1980)
SUMMARY Anomalies of the peripheral auditory system have been reported in major autosomal trisomies. In order to investigate the central auditory pathway, a quantitative and morphometric study of the ventral cochlear nucleus was performed in 2 cases of trisomy 13, 2 cases of trisomy 18 and 1 case of trisomy 21. Data were obtained using a Cambridge Imanco Quantimet 720 Image Analyzing System according to the methods already described. For statistical evaluation, trisomy 13 and 18 cases were considered as group 1-trisomies and compared to full-term controls. Each trisomy was then compared separately to both premature and full term control groups. Trisomy 21 was investigated separately. Quantitative data in trisomy 18 suggest a slight maturational retardation of the ventral cochlear nucleus with respect to gestational age. No significant abnormalities were detected in trisomy 13, aside from those determined by the age difference, when compared to premature controls. The estimated total number of neurons in both trisomies did not differ statistically from that of the control groups. Other brain stem auditory nuclei did not show relevant pathology. Golgi impregnation of the temporal cortex revealed immature neuronal development, especially in trisomy 13. Trisomy 21 showed a greatly reduced number of neurons in the ventral cochlear nucleus, a small nuclear volume, low cell packing density and an abnormally large mean neuronal diameter. The findings
This work was supported by Grant 6-234 from the March of Dimes Birth Defects Foundation. Reprint requests to Dr. D.S. Horoupian, Department of Pathology (Neuropathology), K-438, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, U.S.A. 0022-510X/81/0000-0000/$02.50 © Elsevier/North-Holland Biomedical Press
44
of this investigation are discussed and tentatively correlated to the hearing defects reported in these trisomies.
INTRODUCTION Involvement of the auditory system in all major autosomal trisomies is well established. Structural disorders of the peripheral auditory system are particularly frequent in trisomy D(T-13) and E(T-18). A variety of changes, both in the middle ear and otic capsule, were reported in T-13 (Zellweger 1965: Conen et al. 1966: Kos et a l. 1966; Sando et al. 1970: Black et al. 1971: Lindsay 1973; Saito et al. 1974: Sando et al. 1975: Jaffe 1977). Abnormalities of the external ears and temporal bones were also recognized in T-18 (Smith et al. 1962; Kelemen 1966; Kos et al. 1966; Passarge et al. 1966; Sando et al. 1970; Gacek 1971: Warkany 1971). In Down's syndrome (T-21), osteoid deposition in the spiral tract has been thought to be responsible for the impaired hearing of mongoloid children (Nemanic 1970), but anomalies of the external ears and atresia of the auditory canals are not uncommon (Francois et al. 1967: Fulton and Giffin 1967: Brooks et al. 1972). Data concerning the central auditory pathways in these syndromes are not available so far. except for bilateral herniation of the cochlear nuclei into the 8th cranial nerves in T-13 (Gilbert et al. 1977), As part of a larger quantitative and morphometric study of the human ventral cochlear nucleus, we have therefore investigated this structure in two T-13, two T-18 and one T-21. Findings in other brain stem auditory nuclei will also be presented briefly. The primary auditory cortex was also studied with the classic rapid Golgi technique in the T-13 cases and in one T-18 case (case 3). MATERIALS AND METHODS The cases submitted to this investigation were evaluated with cytogenetic studies. Case 1 was a full-term, newborn, male baby with trisomy 13 syndrome (47 X Y + 13); case 2 was a one-day-old, postmature male baby with 13 translocation trisomy (46 X Y - 13+ t, 13q: 13q); case 3 was a premature male baby of 36 weeks gestation with trisomy 18 syndrome (47 XY+ 18); case 4 was a premature baby girl of 38 weeks gestation with trisomy 18 syndrome (47 XX+ 18), and case 5 was a full-term, 3-month-old male, with Down's syndrome (47 XY+ 21). The brain stems collected at autopsy were fixed in buffered 10
45 t h r o u g h the length o f the nucleus, was stained for cell c o u n t i n g purposes. The quantitative and m o r p h o m e t r i c analysis was performed with a Cambridge I m a n c o Quantimet 720 I m a g e Analyzing C o m p u t e r , according to the m e t h o d already described (Gandolfi et al. 1980). Specimens at different levels o f the brain stem, including the superior olivary complex, inferior colliculi and medial geniculate bodies were also collected. Representative sections f r o m these nuclei were stained with cresyl violet and by Bodian and Heidenhain techniques. Blocks o f tissue f r o m the transverse gyrus o f Heschl f r o m cases 1, 2 and 4 were processed and stained with the rapid Golgi method. RESULTS The quantitative a n d m o r p h o m e t r i c evaluation o f the ventral cochlear nucleus in each trisomy case is reported in Table 1, which shows the various predetermined cell size classes within the nucleus (left column) and the n u m b e r o f cells counted in each class. The headings listed at the b o t t o m o f the table give the estimated total n u m b e r o f neurons, the mean volume o f the nucleus, the mean diameter o f the neurons and the cell packing density. F o r the purpose o f statistical analysis cases 1, 2, 3 and 4 were considered TABLE 1 QUANTITATIVE DATA FROM GROUP 1-TRISOMIES (CASE 1 THROUGH 5 IN PROGRESSIVE ORDER) S I ZE C:L 8 S :-2
T R I S 0 r,1'II{' 1:3
TR I ~{~0; rt 'I~[ 1 :'::
mR I S 0 MIl" 1 :::
ITR I :!i;0 r'l'Y' 1 ',~:
il 0 N~,]• :---; :~;'Ill'f']D~:lZ~r,lE
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 10 12 t4 16 1:-3
167 I :-,'44 29.09 5133 7194 6248
20
:3246
22
956 167
138 L::12 2277 :3696 :3891
7:016 :34:-',7
225 1800 40.'---12 4290 3'?.60 :-1270
:]05 462 1:]70 4103 59'-:'.9 7464
79 62 I n9 442 '?94 19,10
2020
7071
2476
3156
1068
56'.-32
2556
26
2465 128E',
4:37 14e.
2:339 906
2023 1475
28
0
451
30 32 :34
0 0 0
:36 38 40
0
77 :31 7 :-:
0 0
0 0
>40
0
0
TI]TAL VOLUME M E S N DIRM. CE L L S.."MMt:.::
27390 2. 543 15.48 10770
24796 1. 804 17.59 13744
24 26
46
208
9:36
20 11 3
65 11 7
404 188 71
:3 0
0 3 0
0 0
21:331 CI, 9:-:9 14. ',s:6 21577
0
:36505 1. E',:",4 17. I-.'3 1'9:-:72
10 :_": 0 0
1:3638 2. 097 21.11 6504
46 TABLE 2 F U L L - T E R M ( G R O U P 2a) A N D P R E M A T U R E ( G R O U P 2b) C O N T R O L CASES G r o u p 2b
Group 2a Case
Age (gestational)
Sex
Case
Age (gestational)
Sex
1
full-term full-term full-term
M M M
I 2 3 4 5
20 20 23 26 34
N,,A N/A M M M
3
wks Twin A wks Twin B wks wks wks
N,A = not awiihtble.
TABLE 3 C O M P U T E R P R I N T O U T S H O W I N G STATISTICAL E V A L U A T I O N BETWEEN TRISOMY-18 CASES A N D F U L L - T E R M C O N T R O L S ( G R O U P 2a) TRISOMY
18
.'~ ,,.
N=
SIZE
~'""..-,. F U L L
I---TliSOM'(
C L FiS S .
.
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.
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.
.
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.
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.
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.
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8
265
10
1131
12 14
2951 4197 4 ~80 5367 4_46 ' .:, :3380
16 18 20 ,.,-°-' ~4 " "6 28 30 32 34 3.6 38 40 >48 TOTRL VOLUME HEAH DIAM. CELLS.'MM+3
18--!
I'lE FIN .
TERM
S E I"l .
.
~
526 127 43 II 5 2 2 0
0 ",,~ ~ o ~-I B
I, 44f 16.34 20475
It=
3
I---C:l-it.ll'f~l,3L'-:.-
...... I
f'lE A H
:5E M
F'':7
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
t,..... ~.,ci.
I ".,c,o
tl'llillL;;L:;.
10'31 94
i 0;08 -'- q-' 2526 .:':~.I. ;2 c~5 l
3 ',:313 v,'. 2:3 0 2 .2 F,
281 ]841 :28:3 :-3 ,D2 8 9 710(.I g i :':F: 4 ~:21]: !9?8 657 !76 3
Pl
......
11 :-:2
....
I
D J c: .i z.
-
731
.....
I ::;:4
......
i,i
......
tl
- -
-
....... I
.....
i
. . . .
('I
......
H
i3
(.
0 ~:io= ...... O. 45 1.48 I 102
KS
1S 7 2tl
21 '.:',fl .--' :".,:-:4 i = ::; ~.'I
:7551
:3 :-'.. I 0..4 0.E% 710
......
.
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..... .... ---0. 010
47 together as G r o u p l itrisomies, because their age range was close to the perinatal period. This g r o u p was c o m p a r e d to n o r m a l control full-term babies ( G r o u p 2a, Table 2). T-13 cases were also c o m p a r e d with T-18 cases. Each o f the trisomies was then c o m p a r e d separately to the full-term controls ( G r o u p 2a) and to a series o f premature infants at earlier developmental stages ( G r o u p 2b, Table 2). The results are shown in Tables 3 and 4. The D o w n ' s s y n d r o m e case was considered separately (Table 1, right column). The m o r p h o l o g i c and qualitative study o f other brain stem a u d i t o r y nuclei and pathways did not disclose a n y significant change. Only in case 3 a peculiar vacuolar change was noted in the neuropil o f the superior olivary complex especially along its medial surface. A l t h o u g h not an artefact, the significance o f this finding in T-18 remains unclear. The t o p o g r a p h i c distribution o f the a u d i t o r y nuclei along the brain stem a n d their relationship to adjacent structures were maintained. The pyramidal neurons o f the superior temporal gyrus in T-13 cases were very i m m a t u r e and virtually lacking basilar dendrites. The branches o f the apical dendrites were attenuated, short and bearing only few thin spines. The cortex seemed to have attained a developmental stage typical o f a b o u t 28 weeks gestation (Purpura 1975). In T-18 (case 3) m a n y cells o f the temporal cortex seemed to have TABLE 4 COMPUTER PRINTOUT SHOWING STATISTICAL EVALUATION BETWEEN TRISOMY-18 AND PREMATURE CONTROLS (GROUP 2b) ; R I $ 0 M"? 1 $
I',1= ,..--'
$ IZ E
V >;.
"l' C, H i1 E F' _':n_t-I T P i-I L !:_ H = 5
~ - - - T R I -;0 M",' I ,,E---- !
C L R S ~-;
M E FIN
8
'.-;E H
..:'~5
4(~
! ........C C H T P C I. :i!...........!
ME FIfl 1 51
i0 I2 14
1 131 29 5 1 4 19 7
669 1 ~"E i 94
5 5:3 27S9 ~;9 '?8
1~
4'? 8 (l
1 0 2. 0
,:: :::2 ~::
1 '5; 2O ~-.:' :' 24
=,:::~:? 45 46 :. :-',E:0 1:2,',?,',-~
2 0'? 7 2526 2 ::',1 2 9 51
5 ,:'31 :!',1 2 5 7' '? 2, 12 5
.
.
.
.
2',-',
12 7
•:,,=
11 5 2 2
.
•_ , j
81
2 ',-:',9 1 8
9 2 2 2 0 0 ? 5 ',El,:'
MEFtH DII~M,
1.44 16.34
O. 45 1.4:_=:
C E L L S ..."MM .t :3
2 C14.5
1 1 0 ;2
":4 :-'-:6 S ',--::
49 >40 T 0 T FtL VOLUME
O O
'SE M
1? 1 I. ,13
'ZE ":'
4 19 226 2 5 ~ii 21 2 6 :]; 1 1 L}
(:!
I1
20,4 'd:Ji:
0. 050
12 4 1 1 :!!:
~:::I
] 5..(i)
0.050
::3,4 1
~3 2 6 0 'i~8 1. :-:2
F' :::
El. 1 1
~ i ~ ] 5 ~~
48 acquired features of 33 34 week elements. There was a greater concentration of long thin spines on the apical dendrites than usual for the 36th week of gestation. A conspicuous paucity of basilar dendrites was found in the smaller pyramids of the motor cortex. The overall developmental appearance of neurons was that of a 34-week-old fetus (Purpura 1975). DISCUSSION
Statistical evaluation between G r o u p 1-trisomies and G r o u p 2a revealed significant differences only in the mean volume of the nucleus and in the cell packing density. G r o u p 1 trisomies, showed a nuclear volume which was less than half that of the controls (P < 0.05), and a number of cells/mm 3 that was almost double (P < 0.05). Since the estimated total number of neurons and their mean diameter did not statistically differ between the two groups, it was argued that the larger volume of the nucleus in the normals was due to a larger amount of neuropil. No differences were found a m o n g the various cell classes. When comparing T-18 with T-13 cases, a statistically significant difference was found only in the cell packing density, which was 60°o higher in T-18 cases (P < 0.05). Furthermore, in T-18 the numerical value of the nuclear volume was less than half that of the full-term controls, the difference being not statistically significant probably due to our small sample size (Table 3). These findings, however, were not detected when T-18 cases were compared to G r o u p 2b controls, including the cases of earlier gestational age. The estimated total number of neurons, the cell packing density and the mean nuclear volume between the two groups showed almost the same numerical values (Table 4). Since the gestational age of T-18 cases was 36 and 38 weeks, respectively, these data strongly point to retarded maturation of the ventral cochlear nucleus in T-18. Indeed in immature brains the neurons are packed in a smaller volume than in full-term babies or adults (Gandolfi et al. 1980). The small size of the VCN in T-18 cases is also consistent with the overall smallness of the brain reported in this syndrome by Passarge et al. (1966) and Sumi (1970). In the evaluation between T-13 cases and G r o u p 2a no statistically significant differences were found. Comparing the full-term T- 13 cases with the younger controls (Group 2b), the nuclear volume of the former was significantly larger (P < 0.05). The cell packing density was lower in T-13 cases, but not significantly different from that of the controls. These data are probably related to the difference in age between the two groups. On the other hand, the Golgi technique demonstrated maturational retardation of neurons in the auditory cortex especially of T- 13 cases. This observation was reported by Marin-Padilla (1974) in the motor cortex of a newborn with 13-15 trisomy. Our findings, however, were not restricted to Heschl's gyrus, but involved the frontal, motor and visual cortex as well. Since our quantitative data have not shown a pathologically reduced number of neurons in the VCN in these two types of trisomies, it is possible that the hearing impairment reported in these syndromes may be related to developmental abnormalities at the cortical level in addition to those described in the peripheral auditory system.
49 In the case with D o w n ' s syndrome (Table 1), the estimated total number of 13,638 neurons in the ventral cochlear nucleus was lower than that of both control groups and the other trisomies. The neuronal mean diameter, which was 21.11 lain exceeded that of full-terms and even of adults, which has been shown to be 17.60 ~tm (Gandolfi et al. 1980). The volume of the nucleus was smaller than that of the full-term babies, and much lower than that of the other trisomies. MarinPadilla (1976) has reported intrinsic vacuolar changes involving the dendrites and cell bodies, as well as neuronal fragmentation and necrosis in the m o t o r cortex of a child with D o w n ' s syndrome. He postulated that a "basic anomaly, possibly related to the genetic disorder affects primarily some cortical neurons causing them to undergo progressive degeneration terminating in cell fragmentation and death". Our quantitative findings in the ventral cochlear nucleus suggest that a similar degenerative process might have taken place in earlier phases of life and accounts for the reduction in the number of neurons in this nucleus. Those neurons which have survived may have undergone hypertrophy. The relative paucity of neurons in the ventral cochlear nucleus could therefore, at least in part, represent a definite morphological basis for the sensorineural hearing loss reported in this syndrome (Rigrodsky 1961; Glovsky 1966; Fulton 1967). Our finding of fewer neurons in the V C N also correlates well with previous reports that in this syndrome the cortex shows a reduced number of neurons (Hill 1908; Apert 1914; Davidoff 1928; Jervis 1948; Jacob 1956; Ben da 1969). Recently this observation was further confirmed by quantitative methods (Crapper et al. 1975; Ball and Nuttal 1979). It is, however, emphasized that our data derive from only a single case of Down's syndrome, and their interpretation should be considered as preliminary until other cases are studied in similar ways. ACKNOWLEDGEMENTS
The authors thank Dr. R.D. Terry, Chairman, Department of Pathology, for making the Quantimet facilities available and for helping with the manuscript. They are grateful to Dr. D. Purpura, Department of Neuroscience, for interpreting the Golgi preparations. Dr. I. Rapin, Principal Investigator and Dr. K. Suzuki are acknowledged for their help and Dr. L. Solomon (Bronx Lebanon Hospital) for referring case 3. The authors wish to acknowledge the Kresge Foundation for having provided the funds to purchase the Image Analyzing Apparatus. REFERENCES Apert, E. (1914) Le mongolisme (idiotie mongoloide; arri6ration mongoloide), Monde mkd. (Par&), 24:578 588. Ball, M.J. and K. Nuttal (1979) Neurofibrillary tangles, granulovacuolar degeneration and neuron loss in Down syndrome Quantitativecomparison with Alzheimer dementia, Ann. Neurol., 7:462 465. Benda, C.E. (1969) Down's Syndrome - - Mongolism and Its Management, revised edition, Grune and Stratton, New York, London. Black, F. O., 1. Sando, J. A. Wagner and W. G. Hemenway (1971) Middle and inner ear abnormalities 13-15 (DI) trisomy, Arch. Otolaryng., 93:615 619.
50 Brooks, D. N., H. Wooley and G. C. Kanjilal (1972) Hearing loss and middle ear disorders in patients with Down's syndrome (mongolism), J. ment. de[i'c. Res., 16:21 29. Conen, P.E., B. Erkmann and C. Metaxotou (1966) The ~'D" syndrome Report of f\~ur trisomic and one D/D transtocation case, Amer. J. Dis. Child., 111 : 236 247. Crapper, D.R.. A.J. Dalton, M. Skopitz et al. (1975) Alzheimer degeneration ill Down syndrome, Arch. Neurol. (Chic.), 33:618 623. Davidoff, L. M. (1928) The brain in mongolian idiocy A report of tell cases, Arch. Neurol. Psvchiat.. 20:1229 1257. Francois, J., M.T. Matton-van Leuven and P. Kluyskens (1967) Cytogenetic study of otosclerosis, Acta Genet. med. (Roma), 16: 124~158. Fulton, R. T. and C. S. Giffin (1967) Audiological-otological considerations with the mentally retarded, Ment. Retard., 5: 26-31. Gacek, R. (1971) The pathology of hereditary sensorineural hearing loss, Ann. Otol. (St. Louis;, 80 : 289-298. Gandolfi, A., D.S. Horoupian and R.M. De Teresa (1981) Quantitative and cytometric analysis of the ventral cochlear nucleus in man, J. neurol. Sci., 50:443 455. Gilbert, A.G., A.W. Dudley, Jr., L. Meisner, C. Viseskul and G. De Venecia (1977) New neurological findings in trisomy 13, Arch. Path. Lab. Med., 101:540 544. Glovsky, L. (1966) Audiological assessment of a mongoloid population, Training School Bull., 63 : 27 36. Hill, W. B. (1908) Mongolism and its pathology An analysis of eight cases, Quart. J. Med., 2:49 68. Jacob, H. (1956) Mongolismus. In: O. Lubarsch, F. Henke and R. R6ssle (Eds.), Handbuch dcr Speziellen Pathologischen Anatomie undHistoloeie, Vol. 13, Part 4, Springer-Verlag, Berlin, pp. 82 98. Jaffe, B. F. (1977) Hearing Loss in Chihtren A Comprehensive Text, University Park Press, Baltimore, London, Tokyo, Chapt. 2, pp. 40 43. Jervis, G.A. (1948) Early senile dementia in mongoloid idiocy, Amer. J. Psyehiat., 105:102 106. Kelemen, G., C. Hooft and P. Kluyskens (1968) The inner ear in autosomal trisomy, Pract. Otorhinolao,ng., 30:251 258. Kos, A.O., H.F. Schuknecht and A.J. Singer (1966) Temporal bone studies in 13 15 and 18 trisomy syndrome, Arch. Otolaryng., 83:439 445. Lindsay, J.R. (1973) Profound childhood deafness Inner ear pathology, Ann. Otol. /St. Louis~, 822 (Suppl. 5): 1 12l. Marin-Padilla, M. (1974) Structural organization of the cerebral cortex (motor area) in human " chromosomal aberrations A Golgi study, Part I (D 1 (13~ 15) trisomy, Patau syndrome), Brain Res., 66:375 391. Marin-Padilla, M. (1976) Pyramidal cell abnormalities ill the motor cortex of a child with Down's syndrome A Golgi study, J. comp. Neurol., 167:63 82. Miglets, A.W., D. Schulter, E. Ruppert and D.J. Lira (1975) Trisomy 18 A temporal bone report, Arch. Otolarvng., 101: 433-437. Nemanic, J.K. (1970) Down's syndrome and presbyacusis, Lancet, ii: 670 671. Passarge, E., C. W. True, W.T. Sueoka, N.R. Baumgartner and K.R. Keer (1966) Mallbrmations of the central nervous system in trisomy 18 syndrome, J. Pediat., 69:771 778. Purpura, D.P. (1975) Morphogenesis of visual cortex in the preterm infant. In : M. A. B. Brazier (Ed.), Growth and Development O['the Brain, Raven Press, New York, pp. 33 49. Rigrodsky, S., F. Prunty and L. Glovsky (1961) A study of the incidence, types and associated etiologies of hearing loss in an institutionalized mentally retarded population, Trn~. Sch. Bull., 58:30 44. Saito, H., Y. Okana, M. Furuta, H. Asamoto, H. Fujita and T. Takeuchi (1974) Temporal bone findings in trisomy D, Arch. Otolao'ng.. 100:386 389. Sando, 1., k. Bergstrom. R.P. Wood and W. G. Hemenway (1970) Temporal bone findings in Trisomy 18 syndrome, Arch. Otolacvnx,., 91:552 559. Sando, I., A. Leiberman. L. Bergstrom, S. lzumi and R. P. Wood (1975) Temporal bone histopathologic findings in trisomy 13 syndrome, Am~. Otol. (St. Louis), 84 (Suppl. 21): 3 19. Smith, D.W., K. Patau, E. Therman and S.L. lnhorn (1962) The No. 18 trisomy syndrome, J. Pedlar.. 60 : 513 527. Sunli, S. M. (1970) Brain mallbrmations in the trisomy 18 syndrome, Brain, 93:821 830. Warkany, J. (1971) Congenital MalJbrmations Notes and Comments, Year Book Medical Publishers, Inc.. Sect. 3, Chapt. 37, pp. 296 339. Zellweger, H. (1965) Chromosomal aberrations and their signiticance lbr ophthalmo-otorhinolaryngology, Trans. Amer. Acad. Ophthal. Otolaryn~., 69:33 50.
43
Elsevier/North-Holland Biomedical Press
P A T H O L O G Y OF T H E A U D I T O R Y SYSTEM 1N A U T O S O M A L TRISOMIES WITH MORPHOMETRIC AND QUANTITATIVE STUDY OF T H E V E N T R A L C O C H L E A R N U C L E U S
ANGELO GANDOLFI, DIKRAN S. HOROUPIAN and RICHARD M. DE TERESA Department Of' Pathology (Neuropathology), The Saul R. Korey Department of" Neurology (Pediatric Neurology) and The Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College qf Medicine, Bronx, N Y 10461 (U.S.A.)
(Received 20 October, 1980) (Accepted 3 December, 1980)
SUMMARY Anomalies of the peripheral auditory system have been reported in major autosomal trisomies. In order to investigate the central auditory pathway, a quantitative and morphometric study of the ventral cochlear nucleus was performed in 2 cases of trisomy 13, 2 cases of trisomy 18 and 1 case of trisomy 21. Data were obtained using a Cambridge Imanco Quantimet 720 Image Analyzing System according to the methods already described. For statistical evaluation, trisomy 13 and 18 cases were considered as group 1-trisomies and compared to full-term controls. Each trisomy was then compared separately to both premature and full term control groups. Trisomy 21 was investigated separately. Quantitative data in trisomy 18 suggest a slight maturational retardation of the ventral cochlear nucleus with respect to gestational age. No significant abnormalities were detected in trisomy 13, aside from those determined by the age difference, when compared to premature controls. The estimated total number of neurons in both trisomies did not differ statistically from that of the control groups. Other brain stem auditory nuclei did not show relevant pathology. Golgi impregnation of the temporal cortex revealed immature neuronal development, especially in trisomy 13. Trisomy 21 showed a greatly reduced number of neurons in the ventral cochlear nucleus, a small nuclear volume, low cell packing density and an abnormally large mean neuronal diameter. The findings
This work was supported by Grant 6-234 from the March of Dimes Birth Defects Foundation. Reprint requests to Dr. D.S. Horoupian, Department of Pathology (Neuropathology), K-438, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, U.S.A. 0022-510X/81/0000-0000/$02.50 © Elsevier/North-Holland Biomedical Press
44
of this investigation are discussed and tentatively correlated to the hearing defects reported in these trisomies.
INTRODUCTION Involvement of the auditory system in all major autosomal trisomies is well established. Structural disorders of the peripheral auditory system are particularly frequent in trisomy D(T-13) and E(T-18). A variety of changes, both in the middle ear and otic capsule, were reported in T-13 (Zellweger 1965: Conen et al. 1966: Kos et a l. 1966; Sando et al. 1970: Black et al. 1971: Lindsay 1973; Saito et al. 1974: Sando et al. 1975: Jaffe 1977). Abnormalities of the external ears and temporal bones were also recognized in T-18 (Smith et al. 1962; Kelemen 1966; Kos et al. 1966; Passarge et al. 1966; Sando et al. 1970; Gacek 1971: Warkany 1971). In Down's syndrome (T-21), osteoid deposition in the spiral tract has been thought to be responsible for the impaired hearing of mongoloid children (Nemanic 1970), but anomalies of the external ears and atresia of the auditory canals are not uncommon (Francois et al. 1967: Fulton and Giffin 1967: Brooks et al. 1972). Data concerning the central auditory pathways in these syndromes are not available so far. except for bilateral herniation of the cochlear nuclei into the 8th cranial nerves in T-13 (Gilbert et al. 1977), As part of a larger quantitative and morphometric study of the human ventral cochlear nucleus, we have therefore investigated this structure in two T-13, two T-18 and one T-21. Findings in other brain stem auditory nuclei will also be presented briefly. The primary auditory cortex was also studied with the classic rapid Golgi technique in the T-13 cases and in one T-18 case (case 3). MATERIALS AND METHODS The cases submitted to this investigation were evaluated with cytogenetic studies. Case 1 was a full-term, newborn, male baby with trisomy 13 syndrome (47 X Y + 13); case 2 was a one-day-old, postmature male baby with 13 translocation trisomy (46 X Y - 13+ t, 13q: 13q); case 3 was a premature male baby of 36 weeks gestation with trisomy 18 syndrome (47 XY+ 18); case 4 was a premature baby girl of 38 weeks gestation with trisomy 18 syndrome (47 XX+ 18), and case 5 was a full-term, 3-month-old male, with Down's syndrome (47 XY+ 21). The brain stems collected at autopsy were fixed in buffered 10
45 t h r o u g h the length o f the nucleus, was stained for cell c o u n t i n g purposes. The quantitative and m o r p h o m e t r i c analysis was performed with a Cambridge I m a n c o Quantimet 720 I m a g e Analyzing C o m p u t e r , according to the m e t h o d already described (Gandolfi et al. 1980). Specimens at different levels o f the brain stem, including the superior olivary complex, inferior colliculi and medial geniculate bodies were also collected. Representative sections f r o m these nuclei were stained with cresyl violet and by Bodian and Heidenhain techniques. Blocks o f tissue f r o m the transverse gyrus o f Heschl f r o m cases 1, 2 and 4 were processed and stained with the rapid Golgi method. RESULTS The quantitative a n d m o r p h o m e t r i c evaluation o f the ventral cochlear nucleus in each trisomy case is reported in Table 1, which shows the various predetermined cell size classes within the nucleus (left column) and the n u m b e r o f cells counted in each class. The headings listed at the b o t t o m o f the table give the estimated total n u m b e r o f neurons, the mean volume o f the nucleus, the mean diameter o f the neurons and the cell packing density. F o r the purpose o f statistical analysis cases 1, 2, 3 and 4 were considered TABLE 1 QUANTITATIVE DATA FROM GROUP 1-TRISOMIES (CASE 1 THROUGH 5 IN PROGRESSIVE ORDER) S I ZE C:L 8 S :-2
T R I S 0 r,1'II{' 1:3
TR I ~{~0; rt 'I~[ 1 :'::
mR I S 0 MIl" 1 :::
ITR I :!i;0 r'l'Y' 1 ',~:
il 0 N~,]• :---; :~;'Ill'f']D~:lZ~r,lE
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 10 12 t4 16 1:-3
167 I :-,'44 29.09 5133 7194 6248
20
:3246
22
956 167
138 L::12 2277 :3696 :3891
7:016 :34:-',7
225 1800 40.'---12 4290 3'?.60 :-1270
:]05 462 1:]70 4103 59'-:'.9 7464
79 62 I n9 442 '?94 19,10
2020
7071
2476
3156
1068
56'.-32
2556
26
2465 128E',
4:37 14e.
2:339 906
2023 1475
28
0
451
30 32 :34
0 0 0
:36 38 40
0
77 :31 7 :-:
0 0
0 0
>40
0
0
TI]TAL VOLUME M E S N DIRM. CE L L S.."MMt:.::
27390 2. 543 15.48 10770
24796 1. 804 17.59 13744
24 26
46
208
9:36
20 11 3
65 11 7
404 188 71
:3 0
0 3 0
0 0
21:331 CI, 9:-:9 14. ',s:6 21577
0
:36505 1. E',:",4 17. I-.'3 1'9:-:72
10 :_": 0 0
1:3638 2. 097 21.11 6504
46 TABLE 2 F U L L - T E R M ( G R O U P 2a) A N D P R E M A T U R E ( G R O U P 2b) C O N T R O L CASES G r o u p 2b
Group 2a Case
Age (gestational)
Sex
Case
Age (gestational)
Sex
1
full-term full-term full-term
M M M
I 2 3 4 5
20 20 23 26 34
N,,A N/A M M M
3
wks Twin A wks Twin B wks wks wks
N,A = not awiihtble.
TABLE 3 C O M P U T E R P R I N T O U T S H O W I N G STATISTICAL E V A L U A T I O N BETWEEN TRISOMY-18 CASES A N D F U L L - T E R M C O N T R O L S ( G R O U P 2a) TRISOMY
18
.'~ ,,.
N=
SIZE
~'""..-,. F U L L
I---TliSOM'(
C L FiS S .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
8
265
10
1131
12 14
2951 4197 4 ~80 5367 4_46 ' .:, :3380
16 18 20 ,.,-°-' ~4 " "6 28 30 32 34 3.6 38 40 >48 TOTRL VOLUME HEAH DIAM. CELLS.'MM+3
18--!
I'lE FIN .
TERM
S E I"l .
.
~
526 127 43 II 5 2 2 0
0 ",,~ ~ o ~-I B
I, 44f 16.34 20475
It=
3
I---C:l-it.ll'f~l,3L'-:.-
...... I
f'lE A H
:5E M
F'':7
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
t,..... ~.,ci.
I ".,c,o
tl'llillL;;L:;.
10'31 94
i 0;08 -'- q-' 2526 .:':~.I. ;2 c~5 l
3 ',:313 v,'. 2:3 0 2 .2 F,
281 ]841 :28:3 :-3 ,D2 8 9 710(.I g i :':F: 4 ~:21]: !9?8 657 !76 3
Pl
......
11 :-:2
....
I
D J c: .i z.
-
731
.....
I ::;:4
......
i,i
......
tl
- -
-
....... I
.....
i
. . . .
('I
......
H
i3
(.
0 ~:io= ...... O. 45 1.48 I 102
KS
1S 7 2tl
21 '.:',fl .--' :".,:-:4 i = ::; ~.'I
:7551
:3 :-'.. I 0..4 0.E% 710
......
.
.
.
.
.
.
..... .... ---0. 010
47 together as G r o u p l itrisomies, because their age range was close to the perinatal period. This g r o u p was c o m p a r e d to n o r m a l control full-term babies ( G r o u p 2a, Table 2). T-13 cases were also c o m p a r e d with T-18 cases. Each o f the trisomies was then c o m p a r e d separately to the full-term controls ( G r o u p 2a) and to a series o f premature infants at earlier developmental stages ( G r o u p 2b, Table 2). The results are shown in Tables 3 and 4. The D o w n ' s s y n d r o m e case was considered separately (Table 1, right column). The m o r p h o l o g i c and qualitative study o f other brain stem a u d i t o r y nuclei and pathways did not disclose a n y significant change. Only in case 3 a peculiar vacuolar change was noted in the neuropil o f the superior olivary complex especially along its medial surface. A l t h o u g h not an artefact, the significance o f this finding in T-18 remains unclear. The t o p o g r a p h i c distribution o f the a u d i t o r y nuclei along the brain stem a n d their relationship to adjacent structures were maintained. The pyramidal neurons o f the superior temporal gyrus in T-13 cases were very i m m a t u r e and virtually lacking basilar dendrites. The branches o f the apical dendrites were attenuated, short and bearing only few thin spines. The cortex seemed to have attained a developmental stage typical o f a b o u t 28 weeks gestation (Purpura 1975). In T-18 (case 3) m a n y cells o f the temporal cortex seemed to have TABLE 4 COMPUTER PRINTOUT SHOWING STATISTICAL EVALUATION BETWEEN TRISOMY-18 AND PREMATURE CONTROLS (GROUP 2b) ; R I $ 0 M"? 1 $
I',1= ,..--'
$ IZ E
V >;.
"l' C, H i1 E F' _':n_t-I T P i-I L !:_ H = 5
~ - - - T R I -;0 M",' I ,,E---- !
C L R S ~-;
M E FIN
8
'.-;E H
..:'~5
4(~
! ........C C H T P C I. :i!...........!
ME FIfl 1 51
i0 I2 14
1 131 29 5 1 4 19 7
669 1 ~"E i 94
5 5:3 27S9 ~;9 '?8
1~
4'? 8 (l
1 0 2. 0
,:: :::2 ~::
1 '5; 2O ~-.:' :' 24
=,:::~:? 45 46 :. :-',E:0 1:2,',?,',-~
2 0'? 7 2526 2 ::',1 2 9 51
5 ,:'31 :!',1 2 5 7' '? 2, 12 5
.
.
.
.
2',-',
12 7
•:,,=
11 5 2 2
.
•_ , j
81
2 ',-:',9 1 8
9 2 2 2 0 0 ? 5 ',El,:'
MEFtH DII~M,
1.44 16.34
O. 45 1.4:_=:
C E L L S ..."MM .t :3
2 C14.5
1 1 0 ;2
":4 :-'-:6 S ',--::
49 >40 T 0 T FtL VOLUME
O O
'SE M
1? 1 I. ,13
'ZE ":'
4 19 226 2 5 ~ii 21 2 6 :]; 1 1 L}
(:!
I1
20,4 'd:Ji:
0. 050
12 4 1 1 :!!:
~:::I
] 5..(i)
0.050
::3,4 1
~3 2 6 0 'i~8 1. :-:2
F' :::
El. 1 1
~ i ~ ] 5 ~~
48 acquired features of 33 34 week elements. There was a greater concentration of long thin spines on the apical dendrites than usual for the 36th week of gestation. A conspicuous paucity of basilar dendrites was found in the smaller pyramids of the motor cortex. The overall developmental appearance of neurons was that of a 34-week-old fetus (Purpura 1975). DISCUSSION
Statistical evaluation between G r o u p 1-trisomies and G r o u p 2a revealed significant differences only in the mean volume of the nucleus and in the cell packing density. G r o u p 1 trisomies, showed a nuclear volume which was less than half that of the controls (P < 0.05), and a number of cells/mm 3 that was almost double (P < 0.05). Since the estimated total number of neurons and their mean diameter did not statistically differ between the two groups, it was argued that the larger volume of the nucleus in the normals was due to a larger amount of neuropil. No differences were found a m o n g the various cell classes. When comparing T-18 with T-13 cases, a statistically significant difference was found only in the cell packing density, which was 60°o higher in T-18 cases (P < 0.05). Furthermore, in T-18 the numerical value of the nuclear volume was less than half that of the full-term controls, the difference being not statistically significant probably due to our small sample size (Table 3). These findings, however, were not detected when T-18 cases were compared to G r o u p 2b controls, including the cases of earlier gestational age. The estimated total number of neurons, the cell packing density and the mean nuclear volume between the two groups showed almost the same numerical values (Table 4). Since the gestational age of T-18 cases was 36 and 38 weeks, respectively, these data strongly point to retarded maturation of the ventral cochlear nucleus in T-18. Indeed in immature brains the neurons are packed in a smaller volume than in full-term babies or adults (Gandolfi et al. 1980). The small size of the VCN in T-18 cases is also consistent with the overall smallness of the brain reported in this syndrome by Passarge et al. (1966) and Sumi (1970). In the evaluation between T-13 cases and G r o u p 2a no statistically significant differences were found. Comparing the full-term T- 13 cases with the younger controls (Group 2b), the nuclear volume of the former was significantly larger (P < 0.05). The cell packing density was lower in T-13 cases, but not significantly different from that of the controls. These data are probably related to the difference in age between the two groups. On the other hand, the Golgi technique demonstrated maturational retardation of neurons in the auditory cortex especially of T- 13 cases. This observation was reported by Marin-Padilla (1974) in the motor cortex of a newborn with 13-15 trisomy. Our findings, however, were not restricted to Heschl's gyrus, but involved the frontal, motor and visual cortex as well. Since our quantitative data have not shown a pathologically reduced number of neurons in the VCN in these two types of trisomies, it is possible that the hearing impairment reported in these syndromes may be related to developmental abnormalities at the cortical level in addition to those described in the peripheral auditory system.
49 In the case with D o w n ' s syndrome (Table 1), the estimated total number of 13,638 neurons in the ventral cochlear nucleus was lower than that of both control groups and the other trisomies. The neuronal mean diameter, which was 21.11 lain exceeded that of full-terms and even of adults, which has been shown to be 17.60 ~tm (Gandolfi et al. 1980). The volume of the nucleus was smaller than that of the full-term babies, and much lower than that of the other trisomies. MarinPadilla (1976) has reported intrinsic vacuolar changes involving the dendrites and cell bodies, as well as neuronal fragmentation and necrosis in the m o t o r cortex of a child with D o w n ' s syndrome. He postulated that a "basic anomaly, possibly related to the genetic disorder affects primarily some cortical neurons causing them to undergo progressive degeneration terminating in cell fragmentation and death". Our quantitative findings in the ventral cochlear nucleus suggest that a similar degenerative process might have taken place in earlier phases of life and accounts for the reduction in the number of neurons in this nucleus. Those neurons which have survived may have undergone hypertrophy. The relative paucity of neurons in the ventral cochlear nucleus could therefore, at least in part, represent a definite morphological basis for the sensorineural hearing loss reported in this syndrome (Rigrodsky 1961; Glovsky 1966; Fulton 1967). Our finding of fewer neurons in the V C N also correlates well with previous reports that in this syndrome the cortex shows a reduced number of neurons (Hill 1908; Apert 1914; Davidoff 1928; Jervis 1948; Jacob 1956; Ben da 1969). Recently this observation was further confirmed by quantitative methods (Crapper et al. 1975; Ball and Nuttal 1979). It is, however, emphasized that our data derive from only a single case of Down's syndrome, and their interpretation should be considered as preliminary until other cases are studied in similar ways. ACKNOWLEDGEMENTS
The authors thank Dr. R.D. Terry, Chairman, Department of Pathology, for making the Quantimet facilities available and for helping with the manuscript. They are grateful to Dr. D. Purpura, Department of Neuroscience, for interpreting the Golgi preparations. Dr. I. Rapin, Principal Investigator and Dr. K. Suzuki are acknowledged for their help and Dr. L. Solomon (Bronx Lebanon Hospital) for referring case 3. The authors wish to acknowledge the Kresge Foundation for having provided the funds to purchase the Image Analyzing Apparatus. REFERENCES Apert, E. (1914) Le mongolisme (idiotie mongoloide; arri6ration mongoloide), Monde mkd. (Par&), 24:578 588. Ball, M.J. and K. Nuttal (1979) Neurofibrillary tangles, granulovacuolar degeneration and neuron loss in Down syndrome Quantitativecomparison with Alzheimer dementia, Ann. Neurol., 7:462 465. Benda, C.E. (1969) Down's Syndrome - - Mongolism and Its Management, revised edition, Grune and Stratton, New York, London. Black, F. O., 1. Sando, J. A. Wagner and W. G. Hemenway (1971) Middle and inner ear abnormalities 13-15 (DI) trisomy, Arch. Otolaryng., 93:615 619.
50 Brooks, D. N., H. Wooley and G. C. Kanjilal (1972) Hearing loss and middle ear disorders in patients with Down's syndrome (mongolism), J. ment. de[i'c. Res., 16:21 29. Conen, P.E., B. Erkmann and C. Metaxotou (1966) The ~'D" syndrome Report of f\~ur trisomic and one D/D transtocation case, Amer. J. Dis. Child., 111 : 236 247. Crapper, D.R.. A.J. Dalton, M. Skopitz et al. (1975) Alzheimer degeneration ill Down syndrome, Arch. Neurol. (Chic.), 33:618 623. Davidoff, L. M. (1928) The brain in mongolian idiocy A report of tell cases, Arch. Neurol. Psvchiat.. 20:1229 1257. Francois, J., M.T. Matton-van Leuven and P. Kluyskens (1967) Cytogenetic study of otosclerosis, Acta Genet. med. (Roma), 16: 124~158. Fulton, R. T. and C. S. Giffin (1967) Audiological-otological considerations with the mentally retarded, Ment. Retard., 5: 26-31. Gacek, R. (1971) The pathology of hereditary sensorineural hearing loss, Ann. Otol. (St. Louis;, 80 : 289-298. Gandolfi, A., D.S. Horoupian and R.M. De Teresa (1981) Quantitative and cytometric analysis of the ventral cochlear nucleus in man, J. neurol. Sci., 50:443 455. Gilbert, A.G., A.W. Dudley, Jr., L. Meisner, C. Viseskul and G. De Venecia (1977) New neurological findings in trisomy 13, Arch. Path. Lab. Med., 101:540 544. Glovsky, L. (1966) Audiological assessment of a mongoloid population, Training School Bull., 63 : 27 36. Hill, W. B. (1908) Mongolism and its pathology An analysis of eight cases, Quart. J. Med., 2:49 68. Jacob, H. (1956) Mongolismus. In: O. Lubarsch, F. Henke and R. R6ssle (Eds.), Handbuch dcr Speziellen Pathologischen Anatomie undHistoloeie, Vol. 13, Part 4, Springer-Verlag, Berlin, pp. 82 98. Jaffe, B. F. (1977) Hearing Loss in Chihtren A Comprehensive Text, University Park Press, Baltimore, London, Tokyo, Chapt. 2, pp. 40 43. Jervis, G.A. (1948) Early senile dementia in mongoloid idiocy, Amer. J. Psyehiat., 105:102 106. Kelemen, G., C. Hooft and P. Kluyskens (1968) The inner ear in autosomal trisomy, Pract. Otorhinolao,ng., 30:251 258. Kos, A.O., H.F. Schuknecht and A.J. Singer (1966) Temporal bone studies in 13 15 and 18 trisomy syndrome, Arch. Otolaryng., 83:439 445. Lindsay, J.R. (1973) Profound childhood deafness Inner ear pathology, Ann. Otol. /St. Louis~, 822 (Suppl. 5): 1 12l. Marin-Padilla, M. (1974) Structural organization of the cerebral cortex (motor area) in human " chromosomal aberrations A Golgi study, Part I (D 1 (13~ 15) trisomy, Patau syndrome), Brain Res., 66:375 391. Marin-Padilla, M. (1976) Pyramidal cell abnormalities ill the motor cortex of a child with Down's syndrome A Golgi study, J. comp. Neurol., 167:63 82. Miglets, A.W., D. Schulter, E. Ruppert and D.J. Lira (1975) Trisomy 18 A temporal bone report, Arch. Otolarvng., 101: 433-437. Nemanic, J.K. (1970) Down's syndrome and presbyacusis, Lancet, ii: 670 671. Passarge, E., C. W. True, W.T. Sueoka, N.R. Baumgartner and K.R. Keer (1966) Mallbrmations of the central nervous system in trisomy 18 syndrome, J. Pediat., 69:771 778. Purpura, D.P. (1975) Morphogenesis of visual cortex in the preterm infant. In : M. A. B. Brazier (Ed.), Growth and Development O['the Brain, Raven Press, New York, pp. 33 49. Rigrodsky, S., F. Prunty and L. Glovsky (1961) A study of the incidence, types and associated etiologies of hearing loss in an institutionalized mentally retarded population, Trn~. Sch. Bull., 58:30 44. Saito, H., Y. Okana, M. Furuta, H. Asamoto, H. Fujita and T. Takeuchi (1974) Temporal bone findings in trisomy D, Arch. Otolao'ng.. 100:386 389. Sando, 1., k. Bergstrom. R.P. Wood and W. G. Hemenway (1970) Temporal bone findings in Trisomy 18 syndrome, Arch. Otolacvnx,., 91:552 559. Sando, I., A. Leiberman. L. Bergstrom, S. lzumi and R. P. Wood (1975) Temporal bone histopathologic findings in trisomy 13 syndrome, Am~. Otol. (St. Louis), 84 (Suppl. 21): 3 19. Smith, D.W., K. Patau, E. Therman and S.L. lnhorn (1962) The No. 18 trisomy syndrome, J. Pedlar.. 60 : 513 527. Sunli, S. M. (1970) Brain mallbrmations in the trisomy 18 syndrome, Brain, 93:821 830. Warkany, J. (1971) Congenital MalJbrmations Notes and Comments, Year Book Medical Publishers, Inc.. Sect. 3, Chapt. 37, pp. 296 339. Zellweger, H. (1965) Chromosomal aberrations and their signiticance lbr ophthalmo-otorhinolaryngology, Trans. Amer. Acad. Ophthal. Otolaryn~., 69:33 50.