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West syndrome associated with hyperlexia
West Syndrome Associated with Hyperlexia Naofumi Ichiba, MD
Two patients are reported with West syndrome associated with hyperlexia. They had peculiar linguistic and psychosocial development and autistic behavior, yet began to read Japanese and Chinese characters, numbers, Roman alphabet letters, and trademark letters at 3 years of age. Neuropsychologic, electroencephaiographic, and radiologic studies were performed at 11 years of age in Patient 1 and at l0 years of age in Patient 2. Although the), were able to read fluently with correct intonation, their comprehension was significantly impaired. The neuropsychologic evaluation of both patients demonstrated selective, excellent ability in auditory memory in contrast to impairment of associational abilities, visual retention, and visual constructional abilities. These findings suggested that the functions in the nondominant hemisphere were also impaired. Although children with West syndrome frequently have associated mental retardation, patients with West syndrome associated with hyperlexia have never been reported. A neuropsychologic investigation of epileptic children with mental retardation is necessary for the detection of hyperlexia.
to investigate the causal relationship between hyperlexia and West syndrome, neuropsychologic, electroencephalographic (EEG ~, and radiologic studies were perlbrmed. Case Reports Patient I. Thi~, 1 I year-old boy was r~)n~ alter a n o m m l pn:cntu~cy alld deliver,, and had uneventful development until 4 m o m h s ol age when he experienced a series of Innit ~paslll'< No neurologu: disease v, as round it) his family. On admission at 4 months oI a~c EEG demonstrated h y p s a r r h y t h m i a as illustrated in f:ieure t. and a chnical diagnosis of West syndrome was made Treatmenl with oral administration m ~itamin Ba had no effect. Oral clonazcpan~ (CZP} lre:.ltnlenl ~.~as begun a l t e r n a l i v e h C Z P produced a marked ileduclion i11. aiR| eventually complete control of. seizurer,. He a c m c v e d n o m m l motor development thereafter, but exhibited [×~culiat mcntat and speecI~ develop merit. Although he began to speak at ] \ c m ol age anti used 2 word phrases at 2 years of age, his ~vcept~ve language was re)paired and he could no~ c o m m u m c a t e with others. Hc denumstrated hyperkmelic behavior and poor comact with lYeople around him lle b c e a n to read .lapanese d m r a c t e r s t " h i r a g a n a " t . Chinese characters C ' k a n j ( ' L tlUln hers. R o m a n alphabet letters, and t r a d e m a d ~ letters al +, x'ear,~ of age. despite impaired lingmstic anti social dcveh~mnem. Although lus symptonls
nnproveu ,dightl3 and gl-adu:dl'y
a s h c ~lg\~., h e m a i n t a i n e d
mod-
developmental retardation. Generalized tnllit., clonic smzures o,ct.'u/rctl a~ain at w years o t age. At I 1 years. 4 months of age+ he was evaluated with neuropsychologic, erate
¢~-r I vl*T 6 T6-r ,
Ichiba N. West syndrome associated with hyperlexia. Pediatr Neurol 1990;6:344-8. r~-c 4
~,+o 2
Introduction Children with epilepsy, particularly those with age-dependent epileptic encephalopathy, frequently demonstrate mental retardation during the clinical course [1-3]. The incidence of mental retardation in patients with West syndrome is generally considered to be approximately 90% [4,5]. If precise observations were made of children believed to have mental retardation, some children with characteristic communication disorders might be found. The author found 2 children with West syndrome associated with hyperlexia [6]. No children have been reported previously with West syndrome and hyperlexia. In an attempt
F r o m the Department o f Pediatrics; O k a y a m a University Medical School; O k a y a m a , Japan.
344
PEDIATRIC NEUROLOGY
VoL 6 No. 5
0,-,,
Figure 1,
EEG at age 4 month.~ reveal~ ttypsarrhythmia in Patient I.
C o m m u n i c a t i o n s should be addressed t(+: Dr. lchiba; D e p a r t m e n t of Pediatrics: O k a y a m a University Medical School; ShJkata-cho 2-5 l: O k a y a r n a City, Japan: R e c e i v e d M a r c h 14, 1990; accepted Ma~, 25, 1990.
Case
i. 3-0
*ITPA:
Auditory reception Visual reception Auditory association Visual association Auditory expression Visual expression Auditory closure Visual closure Auditory sequential memory Visual sequential memory Psycholinguistic age(PLA) *Intelligence quotient(IQ): *Bender-Gestalt test: Case 2. *ITPA: Auditory reception Visual reception Auditory association Visual association Auditory expression Visual expression Auditory closure Visual closure Auditory sequential memory Visual sequential memory Psycholinguistic age(PLA) *Intelligence quotient(IQ): *Bender-Gestalt test:
4-0
5-0 ~
7-0
6-0
8-0
age 9-0
,-----,
%
/ 1
4-0
5-0
6-0
7-0
~
8-0
9-0
age i0-0
,
-....:.._ /
Figure 2. Psychologic findings of both patients. EEG, and rudiologic studies. Evaluation of linguistic functioning revealed greamr impairment in receptive than in expressive language abilities, although expressive abililies were also affected. He was able to speak 4 word phrases, bul his speech was telegraphic and conversational language was often paraphasic or tangential in nature. Although he was able to understand single words and sentences, he was unable to comprehend paragraphs. He was able to read fluently with correct intonation and read compulsively, but his comprehension was significantly impaired. The neuropsychologic results are illustrated in Figure 2. He demonstrated right hand, foot, and eye dominance. His IQ, as determined by the Tanaka-Binet method 17l, was 40 which was equivalent to 4 years, g months of age. The psycholinguistic quotient (PLQ) of the Illinois Test of Psycholinguistic Abilities (ITPA) [8] was 35, which was equivalent to 4 years of age, An investigation of the sub-
~
model
tests of ITPA revealed that he had excellent, selective abilities in auditory sequential memory (Fig 2). The score on the Bender-Gestah test by the method described by Koppitz [9] was 12 points, a score equivalent to that of children 5 years, 6 months of age. Although his constructional praxis with paper and pencil was within normal limits, he demonstrated poor figure copying (Fig 3A). He also failed to draw all figures correctly in the visual-retention test determined by the Benton method [10], probably due to constructional impairment (Fig 3B). His IQ, as determined by the Kohs block design test [III. was 45 which was appropriate for the 1Q score determined by the Tanaka-Binet method. Auditory brainstem responses (ABRst revealed normal latencies of waves 1 and V and absolute thresholds of waves I and V below 40 dB. The laterality index (LI) was measured by means of a dichotic listening
J
copy
Figure 3. (A) Copy of drawing models, and renderings by Patient 1 and (B) visual retention test figures, and rendering ~' by Patient 1.
Ichiba: West Syndrome and Hyperlexia
345
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Figure 4. EEG o[ Patient 1 at I0 yew's of age demonstrating I I Hz hypersynchrtmo,~ o~-rhythm. test (DLT) consisting of 25 pairs of 2-syllabic meauingful words and LI (right ear minus left ear plus 100) was 1l(t. He exhibited good auditory discrimination on DLT. The basic EEG pattern disclosed a relatively well-developed I I hz hypersynchronous a-rhythm (Fig 4); a focal spike in the right parietal region was observed. Cranial computed tomography (CT) revealed no abnormalities. Patient 2. This 10-year-old girl was tx)r~ after a normal pregnancy and delivery; she developed normally until the age of 6 months when she experienced a series of" tonic spasms. No neurok)gic disease was found in members of her family. On admission at 6 months of age, EEG disclosed a modified hypsarrhythmia (Fig 5) and a clinical diagnosis of West syndrome was made. She was initially treated with oral vitamin B(, with no effect. Vita|mn B6 treatment was replaced by ACTH. As a result of ACTH therapy, Cortrosyn-Z (synthetic corticotropin) 0.25 mg/day fnr 4 weeks, her seizures were controlled. She experienced nomml motor development thereafter, but demonstrated peculim mental ;rod speech development. Although she began to speak at 1 year of age and used 2-word phrases at 2 years, she exhibited poor interpersonal contact and could not communicate with others. She began to read Japanese and Chinese characters, numbers, Roman alphabet letters, and trademark letters at 3 years of age, despite impaired linguistic and social developmenl. Although her symptoms improved gradually as she grew and she began to write letters at 6 years of age, she remained mildly developmentally retarded. At 10 years, 3 months of age. she was evaluated with neuropsychologic, EEG, and radiologic studies. Evaluation of linguistic functioning revealed greater impairment in receptive than in expressive language development, although expressive abilities were also affected. Spontaneous language was fluent with norrnal produclion; however, conversational language was often paraphasic, secondary to the comprehen sion disorder. She was able to read fluently with correct intonation and
346
PEDIATRIC NEUROLOGY
Vol. 6 No. 5
--N/T ....................
VT.......................
Ntq- . . . . . . . . .
Figure 5. EEG of Patient 2 at 6 ,n~iJ~tlta oJ' age revealing modiJ~ed h~,psarrhythmia.
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EEG o f Patient 2 at 9 years (~/'age demonstrating 10 H: c~-rhythm.
with persistence, but comprehension was significantly impaired. The neumpsychologic results are illustrated in Figure 2. She exhibited righl hand. foot, and eye dominance. Her" 1Q, as determined by the TanakaBmet method, was 78 which was equivalent to 8 years of age. The PLQ of ITPA was 68 which was equivalent to 7 years of age. Investigation of subtests of ITPA revealed better abilities in auditory function than ira visual function, particularly excellent, selective abilities ira both auditory sequential memory and auditory expression. Her score on the Bender-Gestalt test pertormed by the method described by Koppitz was 6 points which was equivalent to 61/,_ years of age. Although her' constructional praxis was normal, her l Q - as determined by the Kohs block design test was 74 which correlated with the IQ score deter mined b) the Tanaka-Binet method. She tailed to draw 3 figures among 10 ira Benton's Visual Retention Test. ABR revealed normal latencies of waves l and V and absolute thresholds of waves [ and V below 40 dB. Ll measured by means of DLT was 108. She demonstrated good auditory discrimination on DLT. At l(I years of age, EEC, revealed a well-developed 10 Hz cz-rhythm in the occipital region (Fig 6) with no epileptic discharges on EEG. Cra nial CT revealed no abnormalities.
Discussion Children with West s y n d r o m e frequently have associated mental retardation, e v e n after their epileptic seizures have been controlled: therefore, mental retardation in children with West syndrome is a m o r e important problem than the suppression o f epileptic seizures. Ichiba and Ohtahara p e r t o r m e d n e u r o p s y c h o l o g i c and EEG studies on patients with both West and L e n n o x - G a s t a u t syndromes
and reported that a n u m b e r of children with a g e - d e p e n d e n t epileptic encephalopathy had a selective defect in association function, particularly in visual association function, more frequently than in children with mental retardation and no epilepsy 112]. Because there are few neuropsychologic studies on patients with mental retardation and epilepsy [13,14], further investigation of the mental function of epileptic children is necessary. Conversely, there are a few children with pervasive disorders who begin to read letters as early as 2-3 years of age {15,161. A m o n g children with precocious reading, m a n y have features characteristic o f psycholinguistic and social behavior as m e n t i o n e d below and are termed hyperlexic, H y p e r l e x i a was initially reported by Silberberg and Silberberg in 1967 161 t o l l o w e d by precise studies by other authors [ 17,181. The proposed concept of hyperlexia is the ability o f patients to recognize words at levels in advance of their intellectual potential. Children with h y p e f l e x i a exhibit m a n y characteristic features (e.g., fluent oral reading, superior verbal memory, autistic behavior, preoccupation with numbers). Two children reported in this study had m a n y clinical features consistent with hyperlexia, T h e y also demonstrated the selective, excellent abilities in auditory sequential m e m o r y already reported in hyperlexia [19,20~; therefore, these 2 patients are believed to be typical cases of hyperlexia. A l t h o u g h there is no report of West
Ichiba: West Syndrome and Hyperlexia 347
syndrome associated with hyperlexia, a considerable number of children with hyperlexia may be overlooked among children with West syndrome: therefore, further neuropsychologic investigation of the mental function of epileptic children is important. The mechanism of hyperlexia is not yet known: however, the primary and essential cognitive deficit is a disorder in speech and language involving a severe inability to process, organize, integrate, and thereby comprehend language whether it be spoken or written l18]. Corresponding to this finding, many authors have reported that the cerebral localization of hyperlexia appears to be in the left posterior temporoparietal auditory association cortex and/or the white matter fibers leading to it [17-19]; however, the further investigations of DLT and the visual constmctional abilities in these 2 patients suggest functions in the nondominant hemisphere are also impaired in children with hyperlexia. Because the defect responsible for West syndrome may not be diffuse but may include defects in multiple areas as reported by Ichiba and Ohtahara 112], a few children with West syndrome may have multiple area defects similar to those reported in hyperlexia. Chugani et al. reported focal parieto-occipito-temporal hypometabolism in cryptogenic West syndrome indicated by positron emission tomography of local cerebral glucose metabolism [211. Microscopic cortical dysplasia was also confirmed by neuropathologic examination of resected cortical tissue. Studies of cerebral blood flow using radioactive xenon in infants with cryptogenic spasms have shown focal areas of hypoperfusion, often including the parietooccipito-temporal border 122], These findings strongly suggest the anatomic sites resulting in hyperlexia in patients with West syndrome. It is not uncommon for these children with hyperlexia to remain undiagnosed until adulthood; therefore, hyperlexic children should be further evaluated and referred tot appropriate remediation in the areas of language and reading comprehension.
References [1] Matthes A. Psychische veranderungen bei kindlichen epilepsien. Nervenarzt 1961;32:2-7.
348
PEDIATRIC NEUROLOGY
Vol. 6 No. 5
[2]
Doose H. Gerken H. Leonhardl R. ~urzke E. Volz C. Centren-
cephalic myoclonic-astatic pent real: Climca[ and genetic mvestigauons. Neuropaediatrie 1970:2:59-7~. [31 Yamatogi Y. O h t a h a r a S Age delwndeul t'pdeptic encephalopalhy: A longitudinal study Folia Psycbialr Neuro] Jpn I98l:35: 321 ~2 [4] J e a v o n s PM. Bower BD. Dimitrakoudi M Lon~2 term progm,s~s of 150 cases (ff West syndrome. Epilcps~a 1973:14:153-64 [51 Ohtahara :5. Yamatogi Y. Ohtsuka Y Oka E. b, hida l. Pmg~ noses of West syndrome with spectat releret~ce to k.enm~x ~¢vudrome: A developmental study, lu: Wada JA. Penr,. JK. eds. Advances in neurology: The Xth Epilep,sy International N~.l~/l~O';ttlm. Ne~s York: Raven Pres,,. 1980:149 54, [6 S i l b e r b e r g NE. Silberberg MC. H y p e r l e x i a -,pecmt woro recognition skills m young children Except Child 1967:34:41 2 {7 Tanaka K. T a n a k a - B i n e l ' s i n t e l l i e e t t c c test. Ii~kvo: Nihon Bunka Kagakusha. 1970. 18] M i k i Y. Taguchi T. /ieno K. Och K. Hlinoi~ wsl ¢~1 I,%~ch~hugmstic abilities. Tokyo: Nihon Bunka Kagakusha. 1973. [91 Koppitz EM. The Bender Geslall ie~l for young chddren New York: Grunne and Slratton. 1966 [10] Benton AI,. The visual retenlio~ test t~, a constructional prax~s task. Confin Neurol 1962:22:141-55. I l l ] Kohs S(" The block-design test- I Exp Ps)cllot it)20:3: 357 -76 112] i e h i b a N. Ohtahara S. NeuropsychologicaI and electroencephalograph~e study on the West syndrome mtd lhe I,ermox syndrome. No To Haltatsu 19~;4:16:341-5/I. 1131 C h a u d h r y MR. Pond DA. Menial deterioration m cpdeptlc children. J Neurol Neurosurg Psychiatry 1961 24:213-9. 1141 Bourgeois BFD. Prensk3, AL. Palkes HS. ~l~.dent BK. Busch S(; Intelligence m epilepsy: A prospecuve study m ctntdren Ann Neural t983: [4:438-44. [151 Eisenberg L. Kanlter 1, Earl~ Ullalllllc aultsnL 1943-lt)55 Ant J ()rlhopsychiatry 1956:26:556-66. l l 6 l B u r d 1. Fisher W. Knowllon D Kerbaeshian J. Hyperlexta: A n/arker lot unprovement in children with pervasi\,e developmcnta disorder? J Am Acad Child Adolesc Ps 3 chiatrv 1987:26:407-12. [171 M e h e g a n CC. Dreifuss FE. HyDerlexta: Exceptional t'eading abilily m brain-damaged children. Neurology 1972:22:1 t(15- I 1 1181 Cohen M. Campbell R. Gelartk~ M. tlyperlexia: A varianl of aphasia or dyslexia. Pediatr Neurol U)87"3:.22-8 [191 H u t t e n l o c h e r PR, Huttenloche~ JA A stud~ ol children with hypertexia. Neurology I973:23:111}7 16 1201 R i c h m a n LC. Kitchell MM. Hyperlexm ,ts a vzumnt ot devel,pmental language disorder. Brain Lang 198:1: 12: 203-12 121] C h u g a n i HT. Shields WD. Shewmon DA. Olson DM. Phelps ME. Peacock WJ. Infantile spasms: I PE.T identifies local cortical dys~enesi,,, n crypmgenic cases for surgical treatment. Ann Neurol 1991): 27:4[~ 13 [22] Dnlac O. C h m m C. Jantbaque I Ptouin E Raynaud C. Infan. tile spasms. Prog Clin Neurosci 1987:2:97-109.
Two patients are reported with West syndrome associated with hyperlexia. They had peculiar linguistic and psychosocial development and autistic behavior, yet began to read Japanese and Chinese characters, numbers, Roman alphabet letters, and trademark letters at 3 years of age. Neuropsychologic, electroencephaiographic, and radiologic studies were performed at 11 years of age in Patient 1 and at l0 years of age in Patient 2. Although the), were able to read fluently with correct intonation, their comprehension was significantly impaired. The neuropsychologic evaluation of both patients demonstrated selective, excellent ability in auditory memory in contrast to impairment of associational abilities, visual retention, and visual constructional abilities. These findings suggested that the functions in the nondominant hemisphere were also impaired. Although children with West syndrome frequently have associated mental retardation, patients with West syndrome associated with hyperlexia have never been reported. A neuropsychologic investigation of epileptic children with mental retardation is necessary for the detection of hyperlexia.
to investigate the causal relationship between hyperlexia and West syndrome, neuropsychologic, electroencephalographic (EEG ~, and radiologic studies were perlbrmed. Case Reports Patient I. Thi~, 1 I year-old boy was r~)n~ alter a n o m m l pn:cntu~cy alld deliver,, and had uneventful development until 4 m o m h s ol age when he experienced a series of Innit ~paslll'< No neurologu: disease v, as round it) his family. On admission at 4 months oI a~c EEG demonstrated h y p s a r r h y t h m i a as illustrated in f:ieure t. and a chnical diagnosis of West syndrome was made Treatmenl with oral administration m ~itamin Ba had no effect. Oral clonazcpan~ (CZP} lre:.ltnlenl ~.~as begun a l t e r n a l i v e h C Z P produced a marked ileduclion i11. aiR| eventually complete control of. seizurer,. He a c m c v e d n o m m l motor development thereafter, but exhibited [×~culiat mcntat and speecI~ develop merit. Although he began to speak at ] \ c m ol age anti used 2 word phrases at 2 years of age, his ~vcept~ve language was re)paired and he could no~ c o m m u m c a t e with others. Hc denumstrated hyperkmelic behavior and poor comact with lYeople around him lle b c e a n to read .lapanese d m r a c t e r s t " h i r a g a n a " t . Chinese characters C ' k a n j ( ' L tlUln hers. R o m a n alphabet letters, and t r a d e m a d ~ letters al +, x'ear,~ of age. despite impaired lingmstic anti social dcveh~mnem. Although lus symptonls
nnproveu ,dightl3 and gl-adu:dl'y
a s h c ~lg\~., h e m a i n t a i n e d
mod-
developmental retardation. Generalized tnllit., clonic smzures o,ct.'u/rctl a~ain at w years o t age. At I 1 years. 4 months of age+ he was evaluated with neuropsychologic, erate
¢~-r I vl*T 6 T6-r ,
Ichiba N. West syndrome associated with hyperlexia. Pediatr Neurol 1990;6:344-8. r~-c 4
~,+o 2
Introduction Children with epilepsy, particularly those with age-dependent epileptic encephalopathy, frequently demonstrate mental retardation during the clinical course [1-3]. The incidence of mental retardation in patients with West syndrome is generally considered to be approximately 90% [4,5]. If precise observations were made of children believed to have mental retardation, some children with characteristic communication disorders might be found. The author found 2 children with West syndrome associated with hyperlexia [6]. No children have been reported previously with West syndrome and hyperlexia. In an attempt
F r o m the Department o f Pediatrics; O k a y a m a University Medical School; O k a y a m a , Japan.
344
PEDIATRIC NEUROLOGY
VoL 6 No. 5
0,-,,
Figure 1,
EEG at age 4 month.~ reveal~ ttypsarrhythmia in Patient I.
C o m m u n i c a t i o n s should be addressed t(+: Dr. lchiba; D e p a r t m e n t of Pediatrics: O k a y a m a University Medical School; ShJkata-cho 2-5 l: O k a y a r n a City, Japan: R e c e i v e d M a r c h 14, 1990; accepted Ma~, 25, 1990.
Case
i. 3-0
*ITPA:
Auditory reception Visual reception Auditory association Visual association Auditory expression Visual expression Auditory closure Visual closure Auditory sequential memory Visual sequential memory Psycholinguistic age(PLA) *Intelligence quotient(IQ): *Bender-Gestalt test: Case 2. *ITPA: Auditory reception Visual reception Auditory association Visual association Auditory expression Visual expression Auditory closure Visual closure Auditory sequential memory Visual sequential memory Psycholinguistic age(PLA) *Intelligence quotient(IQ): *Bender-Gestalt test:
4-0
5-0 ~
7-0
6-0
8-0
age 9-0
,-----,
%
/ 1
4-0
5-0
6-0
7-0
~
8-0
9-0
age i0-0
,
-....:.._ /
Figure 2. Psychologic findings of both patients. EEG, and rudiologic studies. Evaluation of linguistic functioning revealed greamr impairment in receptive than in expressive language abilities, although expressive abililies were also affected. He was able to speak 4 word phrases, bul his speech was telegraphic and conversational language was often paraphasic or tangential in nature. Although he was able to understand single words and sentences, he was unable to comprehend paragraphs. He was able to read fluently with correct intonation and read compulsively, but his comprehension was significantly impaired. The neuropsychologic results are illustrated in Figure 2. He demonstrated right hand, foot, and eye dominance. His IQ, as determined by the Tanaka-Binet method 17l, was 40 which was equivalent to 4 years, g months of age. The psycholinguistic quotient (PLQ) of the Illinois Test of Psycholinguistic Abilities (ITPA) [8] was 35, which was equivalent to 4 years of age, An investigation of the sub-
~
model
tests of ITPA revealed that he had excellent, selective abilities in auditory sequential memory (Fig 2). The score on the Bender-Gestah test by the method described by Koppitz [9] was 12 points, a score equivalent to that of children 5 years, 6 months of age. Although his constructional praxis with paper and pencil was within normal limits, he demonstrated poor figure copying (Fig 3A). He also failed to draw all figures correctly in the visual-retention test determined by the Benton method [10], probably due to constructional impairment (Fig 3B). His IQ, as determined by the Kohs block design test [III. was 45 which was appropriate for the 1Q score determined by the Tanaka-Binet method. Auditory brainstem responses (ABRst revealed normal latencies of waves 1 and V and absolute thresholds of waves I and V below 40 dB. The laterality index (LI) was measured by means of a dichotic listening
J
copy
Figure 3. (A) Copy of drawing models, and renderings by Patient 1 and (B) visual retention test figures, and rendering ~' by Patient 1.
Ichiba: West Syndrome and Hyperlexia
345
~.1,1 t i i i I I_I"~.|i 1 i I I i_IJ-~lll _I l i 1 i I f'l. i I. I .I I. I .lJlJ"ll . . .I I. | i I I I I"11111 I i I
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Figure 4. EEG o[ Patient 1 at I0 yew's of age demonstrating I I Hz hypersynchrtmo,~ o~-rhythm. test (DLT) consisting of 25 pairs of 2-syllabic meauingful words and LI (right ear minus left ear plus 100) was 1l(t. He exhibited good auditory discrimination on DLT. The basic EEG pattern disclosed a relatively well-developed I I hz hypersynchronous a-rhythm (Fig 4); a focal spike in the right parietal region was observed. Cranial computed tomography (CT) revealed no abnormalities. Patient 2. This 10-year-old girl was tx)r~ after a normal pregnancy and delivery; she developed normally until the age of 6 months when she experienced a series of" tonic spasms. No neurok)gic disease was found in members of her family. On admission at 6 months of age, EEG disclosed a modified hypsarrhythmia (Fig 5) and a clinical diagnosis of West syndrome was made. She was initially treated with oral vitamin B(, with no effect. Vita|mn B6 treatment was replaced by ACTH. As a result of ACTH therapy, Cortrosyn-Z (synthetic corticotropin) 0.25 mg/day fnr 4 weeks, her seizures were controlled. She experienced nomml motor development thereafter, but demonstrated peculim mental ;rod speech development. Although she began to speak at 1 year of age and used 2-word phrases at 2 years, she exhibited poor interpersonal contact and could not communicate with others. She began to read Japanese and Chinese characters, numbers, Roman alphabet letters, and trademark letters at 3 years of age, despite impaired linguistic and social developmenl. Although her symptoms improved gradually as she grew and she began to write letters at 6 years of age, she remained mildly developmentally retarded. At 10 years, 3 months of age. she was evaluated with neuropsychologic, EEG, and radiologic studies. Evaluation of linguistic functioning revealed greater impairment in receptive than in expressive language development, although expressive abilities were also affected. Spontaneous language was fluent with norrnal produclion; however, conversational language was often paraphasic, secondary to the comprehen sion disorder. She was able to read fluently with correct intonation and
346
PEDIATRIC NEUROLOGY
Vol. 6 No. 5
--N/T ....................
VT.......................
Ntq- . . . . . . . . .
Figure 5. EEG of Patient 2 at 6 ,n~iJ~tlta oJ' age revealing modiJ~ed h~,psarrhythmia.
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| $ O FV
EEG o f Patient 2 at 9 years (~/'age demonstrating 10 H: c~-rhythm.
with persistence, but comprehension was significantly impaired. The neumpsychologic results are illustrated in Figure 2. She exhibited righl hand. foot, and eye dominance. Her" 1Q, as determined by the TanakaBmet method, was 78 which was equivalent to 8 years of age. The PLQ of ITPA was 68 which was equivalent to 7 years of age. Investigation of subtests of ITPA revealed better abilities in auditory function than ira visual function, particularly excellent, selective abilities ira both auditory sequential memory and auditory expression. Her score on the Bender-Gestalt test pertormed by the method described by Koppitz was 6 points which was equivalent to 61/,_ years of age. Although her' constructional praxis was normal, her l Q - as determined by the Kohs block design test was 74 which correlated with the IQ score deter mined b) the Tanaka-Binet method. She tailed to draw 3 figures among 10 ira Benton's Visual Retention Test. ABR revealed normal latencies of waves l and V and absolute thresholds of waves [ and V below 40 dB. Ll measured by means of DLT was 108. She demonstrated good auditory discrimination on DLT. At l(I years of age, EEC, revealed a well-developed 10 Hz cz-rhythm in the occipital region (Fig 6) with no epileptic discharges on EEG. Cra nial CT revealed no abnormalities.
Discussion Children with West s y n d r o m e frequently have associated mental retardation, e v e n after their epileptic seizures have been controlled: therefore, mental retardation in children with West syndrome is a m o r e important problem than the suppression o f epileptic seizures. Ichiba and Ohtahara p e r t o r m e d n e u r o p s y c h o l o g i c and EEG studies on patients with both West and L e n n o x - G a s t a u t syndromes
and reported that a n u m b e r of children with a g e - d e p e n d e n t epileptic encephalopathy had a selective defect in association function, particularly in visual association function, more frequently than in children with mental retardation and no epilepsy 112]. Because there are few neuropsychologic studies on patients with mental retardation and epilepsy [13,14], further investigation of the mental function of epileptic children is necessary. Conversely, there are a few children with pervasive disorders who begin to read letters as early as 2-3 years of age {15,161. A m o n g children with precocious reading, m a n y have features characteristic o f psycholinguistic and social behavior as m e n t i o n e d below and are termed hyperlexic, H y p e r l e x i a was initially reported by Silberberg and Silberberg in 1967 161 t o l l o w e d by precise studies by other authors [ 17,181. The proposed concept of hyperlexia is the ability o f patients to recognize words at levels in advance of their intellectual potential. Children with h y p e f l e x i a exhibit m a n y characteristic features (e.g., fluent oral reading, superior verbal memory, autistic behavior, preoccupation with numbers). Two children reported in this study had m a n y clinical features consistent with hyperlexia, T h e y also demonstrated the selective, excellent abilities in auditory sequential m e m o r y already reported in hyperlexia [19,20~; therefore, these 2 patients are believed to be typical cases of hyperlexia. A l t h o u g h there is no report of West
Ichiba: West Syndrome and Hyperlexia 347
syndrome associated with hyperlexia, a considerable number of children with hyperlexia may be overlooked among children with West syndrome: therefore, further neuropsychologic investigation of the mental function of epileptic children is important. The mechanism of hyperlexia is not yet known: however, the primary and essential cognitive deficit is a disorder in speech and language involving a severe inability to process, organize, integrate, and thereby comprehend language whether it be spoken or written l18]. Corresponding to this finding, many authors have reported that the cerebral localization of hyperlexia appears to be in the left posterior temporoparietal auditory association cortex and/or the white matter fibers leading to it [17-19]; however, the further investigations of DLT and the visual constmctional abilities in these 2 patients suggest functions in the nondominant hemisphere are also impaired in children with hyperlexia. Because the defect responsible for West syndrome may not be diffuse but may include defects in multiple areas as reported by Ichiba and Ohtahara 112], a few children with West syndrome may have multiple area defects similar to those reported in hyperlexia. Chugani et al. reported focal parieto-occipito-temporal hypometabolism in cryptogenic West syndrome indicated by positron emission tomography of local cerebral glucose metabolism [211. Microscopic cortical dysplasia was also confirmed by neuropathologic examination of resected cortical tissue. Studies of cerebral blood flow using radioactive xenon in infants with cryptogenic spasms have shown focal areas of hypoperfusion, often including the parietooccipito-temporal border 122], These findings strongly suggest the anatomic sites resulting in hyperlexia in patients with West syndrome. It is not uncommon for these children with hyperlexia to remain undiagnosed until adulthood; therefore, hyperlexic children should be further evaluated and referred tot appropriate remediation in the areas of language and reading comprehension.
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