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Papers by Charles Njiokiktjien
Electroencephalography and Clinical Neurophysiology, 1989
In a longitudinal study a selective attention task was administered to ll-13-year-old children. D... more In a longitudinal study a selective attention task was administered to ll-13-year-old children. During this task (employing a combined filter and selective-set paradigm), event-related brain potentials were recorded to study timing and morphology of early and late selection processes. Task performance was prospectively and retrospectively related to neurological optimality at birth and to flash-evoked potential correlates that were registered at the age of five. The results provided evidence that even after 13 years neonatal neurological suboptimality was reflected in task performance, both in reaction time and in electrophysiological data. Task load interacted with group classification according to optimality to the disadvantage of suboptimals. This implied that load demands differentiated between groups. The event-related brain potentials revealed the existence of a negative shift associated with memory load (search-related negativity) at Fz and Cz, and a positive deflection at Pz (P3b) associated with target detection. Cortical activity, expressed in terms of these deflections, appeared to be less pronounced for the suboptimal group.
Journal of the American Academy of Child & Adolescent Psychiatry, 1990
Develop Med Child Neurol, 2008
Agressologie: revue internationale de physio-biologie et de pharmacologie appliquées aux effets de l'agression
Agressologie: revue internationale de physio-biologie et de pharmacologie appliquées aux effets de l'agression
Tijdschrift voor kindergeneeskunde, 2000
... Nijmegen: Katholieke Uni-versiteit, 1988. Jurjens HB, Hendriksen JGM. De Kaufman Assessment B... more ... Nijmegen: Katholieke Uni-versiteit, 1988. Jurjens HB, Hendriksen JGM. De Kaufman Assessment Battery for Children: psychometrische kenmerken en toepasbaarheid. ... The developmental test for visual motor integra-tion. Cleveland: Modern Curriculum Press, 1989. ...
Tijdschrift voor kindergeneeskunde, 2006
Dr. Charles Njiokiktjien, kinderneuroloog en psychiater. Lid van het diagnostiek-en behandelingst... more Dr. Charles Njiokiktjien, kinderneuroloog en psychiater. Lid van het diagnostiek-en behandelingsteam van de Stichting Dysphatische Ontwikkeling, Amsterdam en consulent van het Kinderpsychiatrisch Centrum Triversum, Alkmaar. Correspondentieadres: Honthorststraat 4 1071 DD Amsterdam. Samenvatting Het autismespectrum omvat in aard en ernst variërende stoornissen die hoofdzakelijk het sociale wederkerige contact en de communicatie betreffen, maar die ook tot uiting kunnen komen in stereotiep en/of moeilijk te beïnvloeden gedrag. Soms zijn deze stoornissen betrekkelijk geïsoleerd, vaker gaan zij met een bredere ontwikkelingsstoornis gepaard of maken zelfs deel uit van een verstandelijke handicap. Autisme kan men tegenkomen als onderdeel van het zogenaamde gedragsfenotype van bekende syndromen; soms is autisme verworven na hersenbeschadiging. De diagnostiek is multidisciplinair. Anamnese en observatie door de kinderarts kunnen autisme als gedragsstoornis waarschijnlijk maken. Het is verder zaak autisme te differentiëren van andere ontwikkelingsstoornissen, belangrijke neurologische diagnoses niet te missen, relevant hulponderzoek te doen en de ouders en hun kind de weg te wijzen naar gespecialiseerde behandelaars. Dit artikel richt zich vooral op autisme op de peuter-en kleuterleeftijd. Summary The autism spectrum entails disorders, varying in nature and severity, and concerning mainly social reciprocal contact and communication. There is often stereotypical behaviour or behaviour that is difficult to manage. Autism may occur in isolation, but more often it is embedded in a broader developmental disorder or is even part of a mental handicap. Autism may be part of the so-called behavioral phenotype of a well-known syndrome. Sometimes autism is acquired after postnatal brain damage. The assessment is a multidisciplinary one. History-taking and observation by the pediatrician may make autism as a behavioral diagnosis probable. The pediatricians further task is to differentiate autism from other developmentel disorders, not to miss important neurological diagnoses, to do relevant diagnostic work-up and to refer the child to specialised therapists. This article focusses especially on autism at the infant and kindergarten age.
Nederlands tijdschrift voor geneeskunde, Jan 30, 1971
Nederlands tijdschrift voor geneeskunde, Jan 18, 1970
Annales médico-psychologiques, 1970
Fiziologiia cheloveka
EEG intrahemispheric coherences (HCohs) in the resting state in twenty-four 4 Hz frequency window... more EEG intrahemispheric coherences (HCohs) in the resting state in twenty-four 4 Hz frequency windows between 1 and 51 Hz were studied in 18 children with "non-verbal learning disorder" (NLD) and compared to a group of 18 children with "verbal learning disorder" (VLD). New facts were found in the NLD group. These concern hemispheric balance, expressed as left minus right (L-R) homologous HCohs: 1a). In the high frequencies (25-51 HZ) the number of long-distance HCohs, higher in the right hemisphere (RH), is lower than HCohs, which are higher in the left hemisphere (LH). A reversed interhemispheric asymmetry is seen for short distance HCohs in that band. These asymmetries are not found in the VLD group, and the tendency is even reversed. 1b). In the low frequencies (1-27 Hz) all higher HCohs are more numerous in the RH, irrespective of interelectrode distance (IED). In these bands there are no NLD-VLD group differences; 2). In NLD there is a significant inverse relat...
Fiziologiia cheloveka
The attentional component of cognitive functioning in children might be viewed from several inter... more The attentional component of cognitive functioning in children might be viewed from several interrelated angles that nearly all point to right hemisphere (RH) neural circuits, subserving nonverbal attention. Neuropsychological aspects indicative of RH brain dysfunction are one aspect, studied here. Among children with learning disabilities (LD) we distinguish between LD with emphasis on nonverbal cognitive deficits and LD with verbal dysfunction. We approached this dichotomy by studying the extremes of these two LD categories (89 ss) with respect to attention deficit disorder with (ADHD) or without hyperactivity (ADD). We examined 44 children with at least average verbal IQ (VIQ > or = 95) and lower performance IQ (PIQ at least 25 points lower than VIQ), i.e. the nonverbal group, and 45 children with at least average performance IQ (PIQ > or = 95) and lower verbal IQ (VIQ at least 25 points lower than PIQ). The percentage of AD(H)D among the nonverbal LD group was more than tw...
Electroencephalography and clinical neurophysiology, 1995
Resting EEG interhemispheric and intrahemispheric coherences (ICoh and HCoh) in the theta, alpha ... more Resting EEG interhemispheric and intrahemispheric coherences (ICoh and HCoh) in the theta, alpha and beta bands were studied in 7 patients with agenesis of the corpus callosum (5 children, aged 10-14 years, and 2 adults) and 2 groups of sex- and age-matched normal children and adults (42 subjects). In patients the ICohs (F3/F4, C3/C4, P3/P4, O1/O2) were lower than in the normal sample. The ICoh decrease, corresponding with the completeness of commissural agenesis, showed the essential role of the corpus callosum in interhemispheric EEG synchronization. A remarkable new fact was found, namely lower right hemisphere HCoh in the acallosal patients in comparison to the normals, suggesting reduced connectivity of the right hemisphere. It is assumed that the deviant HCoh patterns in the patients, most pronounced in the beta band, are indicative of compensatory left hemisphere mechanisms, accounting for a specific brain plasticity phenomenon in acallosal subjects.
Nederlands tijdschrift voor geneeskunde, Jan 27, 1993
Acta paedopsychiatrica, 1994
The initial assumptions as to the existence of neurodevelopmental disorders have been confirmed b... more The initial assumptions as to the existence of neurodevelopmental disorders have been confirmed by almost a century of studies focused on the nature and causes of reading disability. Dyslexia is an umbrella term for the various manifestations of reading disabilities, each of which is related to its own complex of neuropsychological dysfunctions, sometimes accompanied by neurological symptoms that can be indicative of the specific location involved. Electro-physiology and neuro-imaging in relation to metabolic activity have also confirmed that, to some extent, there is dysfunction in various cerebral areas, more frequently in the left than in the right hemisphere, less often between the hemispheres (corpus callosum) and outside the classical language areas. The rather rare subtype referred to as visual dyslexia and the inter-modal disconnection type resembling alexia are eclipsed by dyslexias related to spoken language: the dysphonemic (auditory-phonological) subtype and the subtypes...
Electroencephalography and Clinical Neurophysiology, 1989
In a longitudinal study a selective attention task was administered to ll-13-year-old children. D... more In a longitudinal study a selective attention task was administered to ll-13-year-old children. During this task (employing a combined filter and selective-set paradigm), event-related brain potentials were recorded to study timing and morphology of early and late selection processes. Task performance was prospectively and retrospectively related to neurological optimality at birth and to flash-evoked potential correlates that were registered at the age of five. The results provided evidence that even after 13 years neonatal neurological suboptimality was reflected in task performance, both in reaction time and in electrophysiological data. Task load interacted with group classification according to optimality to the disadvantage of suboptimals. This implied that load demands differentiated between groups. The event-related brain potentials revealed the existence of a negative shift associated with memory load (search-related negativity) at Fz and Cz, and a positive deflection at Pz (P3b) associated with target detection. Cortical activity, expressed in terms of these deflections, appeared to be less pronounced for the suboptimal group.
Journal of the American Academy of Child & Adolescent Psychiatry, 1990
Develop Med Child Neurol, 2008
Agressologie: revue internationale de physio-biologie et de pharmacologie appliquées aux effets de l'agression
Agressologie: revue internationale de physio-biologie et de pharmacologie appliquées aux effets de l'agression
Tijdschrift voor kindergeneeskunde, 2000
... Nijmegen: Katholieke Uni-versiteit, 1988. Jurjens HB, Hendriksen JGM. De Kaufman Assessment B... more ... Nijmegen: Katholieke Uni-versiteit, 1988. Jurjens HB, Hendriksen JGM. De Kaufman Assessment Battery for Children: psychometrische kenmerken en toepasbaarheid. ... The developmental test for visual motor integra-tion. Cleveland: Modern Curriculum Press, 1989. ...
Tijdschrift voor kindergeneeskunde, 2006
Dr. Charles Njiokiktjien, kinderneuroloog en psychiater. Lid van het diagnostiek-en behandelingst... more Dr. Charles Njiokiktjien, kinderneuroloog en psychiater. Lid van het diagnostiek-en behandelingsteam van de Stichting Dysphatische Ontwikkeling, Amsterdam en consulent van het Kinderpsychiatrisch Centrum Triversum, Alkmaar. Correspondentieadres: Honthorststraat 4 1071 DD Amsterdam. Samenvatting Het autismespectrum omvat in aard en ernst variërende stoornissen die hoofdzakelijk het sociale wederkerige contact en de communicatie betreffen, maar die ook tot uiting kunnen komen in stereotiep en/of moeilijk te beïnvloeden gedrag. Soms zijn deze stoornissen betrekkelijk geïsoleerd, vaker gaan zij met een bredere ontwikkelingsstoornis gepaard of maken zelfs deel uit van een verstandelijke handicap. Autisme kan men tegenkomen als onderdeel van het zogenaamde gedragsfenotype van bekende syndromen; soms is autisme verworven na hersenbeschadiging. De diagnostiek is multidisciplinair. Anamnese en observatie door de kinderarts kunnen autisme als gedragsstoornis waarschijnlijk maken. Het is verder zaak autisme te differentiëren van andere ontwikkelingsstoornissen, belangrijke neurologische diagnoses niet te missen, relevant hulponderzoek te doen en de ouders en hun kind de weg te wijzen naar gespecialiseerde behandelaars. Dit artikel richt zich vooral op autisme op de peuter-en kleuterleeftijd. Summary The autism spectrum entails disorders, varying in nature and severity, and concerning mainly social reciprocal contact and communication. There is often stereotypical behaviour or behaviour that is difficult to manage. Autism may occur in isolation, but more often it is embedded in a broader developmental disorder or is even part of a mental handicap. Autism may be part of the so-called behavioral phenotype of a well-known syndrome. Sometimes autism is acquired after postnatal brain damage. The assessment is a multidisciplinary one. History-taking and observation by the pediatrician may make autism as a behavioral diagnosis probable. The pediatricians further task is to differentiate autism from other developmentel disorders, not to miss important neurological diagnoses, to do relevant diagnostic work-up and to refer the child to specialised therapists. This article focusses especially on autism at the infant and kindergarten age.
Nederlands tijdschrift voor geneeskunde, Jan 30, 1971
Nederlands tijdschrift voor geneeskunde, Jan 18, 1970
Annales médico-psychologiques, 1970
Fiziologiia cheloveka
EEG intrahemispheric coherences (HCohs) in the resting state in twenty-four 4 Hz frequency window... more EEG intrahemispheric coherences (HCohs) in the resting state in twenty-four 4 Hz frequency windows between 1 and 51 Hz were studied in 18 children with "non-verbal learning disorder" (NLD) and compared to a group of 18 children with "verbal learning disorder" (VLD). New facts were found in the NLD group. These concern hemispheric balance, expressed as left minus right (L-R) homologous HCohs: 1a). In the high frequencies (25-51 HZ) the number of long-distance HCohs, higher in the right hemisphere (RH), is lower than HCohs, which are higher in the left hemisphere (LH). A reversed interhemispheric asymmetry is seen for short distance HCohs in that band. These asymmetries are not found in the VLD group, and the tendency is even reversed. 1b). In the low frequencies (1-27 Hz) all higher HCohs are more numerous in the RH, irrespective of interelectrode distance (IED). In these bands there are no NLD-VLD group differences; 2). In NLD there is a significant inverse relat...
Fiziologiia cheloveka
The attentional component of cognitive functioning in children might be viewed from several inter... more The attentional component of cognitive functioning in children might be viewed from several interrelated angles that nearly all point to right hemisphere (RH) neural circuits, subserving nonverbal attention. Neuropsychological aspects indicative of RH brain dysfunction are one aspect, studied here. Among children with learning disabilities (LD) we distinguish between LD with emphasis on nonverbal cognitive deficits and LD with verbal dysfunction. We approached this dichotomy by studying the extremes of these two LD categories (89 ss) with respect to attention deficit disorder with (ADHD) or without hyperactivity (ADD). We examined 44 children with at least average verbal IQ (VIQ > or = 95) and lower performance IQ (PIQ at least 25 points lower than VIQ), i.e. the nonverbal group, and 45 children with at least average performance IQ (PIQ > or = 95) and lower verbal IQ (VIQ at least 25 points lower than PIQ). The percentage of AD(H)D among the nonverbal LD group was more than tw...
Electroencephalography and clinical neurophysiology, 1995
Resting EEG interhemispheric and intrahemispheric coherences (ICoh and HCoh) in the theta, alpha ... more Resting EEG interhemispheric and intrahemispheric coherences (ICoh and HCoh) in the theta, alpha and beta bands were studied in 7 patients with agenesis of the corpus callosum (5 children, aged 10-14 years, and 2 adults) and 2 groups of sex- and age-matched normal children and adults (42 subjects). In patients the ICohs (F3/F4, C3/C4, P3/P4, O1/O2) were lower than in the normal sample. The ICoh decrease, corresponding with the completeness of commissural agenesis, showed the essential role of the corpus callosum in interhemispheric EEG synchronization. A remarkable new fact was found, namely lower right hemisphere HCoh in the acallosal patients in comparison to the normals, suggesting reduced connectivity of the right hemisphere. It is assumed that the deviant HCoh patterns in the patients, most pronounced in the beta band, are indicative of compensatory left hemisphere mechanisms, accounting for a specific brain plasticity phenomenon in acallosal subjects.
Nederlands tijdschrift voor geneeskunde, Jan 27, 1993
Acta paedopsychiatrica, 1994
The initial assumptions as to the existence of neurodevelopmental disorders have been confirmed b... more The initial assumptions as to the existence of neurodevelopmental disorders have been confirmed by almost a century of studies focused on the nature and causes of reading disability. Dyslexia is an umbrella term for the various manifestations of reading disabilities, each of which is related to its own complex of neuropsychological dysfunctions, sometimes accompanied by neurological symptoms that can be indicative of the specific location involved. Electro-physiology and neuro-imaging in relation to metabolic activity have also confirmed that, to some extent, there is dysfunction in various cerebral areas, more frequently in the left than in the right hemisphere, less often between the hemispheres (corpus callosum) and outside the classical language areas. The rather rare subtype referred to as visual dyslexia and the inter-modal disconnection type resembling alexia are eclipsed by dyslexias related to spoken language: the dysphonemic (auditory-phonological) subtype and the subtypes...