Functional brain imaging in neuropsychiatric disorders of childhood

Investigating sensory response to physical discomfort in children with autism spectrum disorder using near-infrared spectroscopy

Self-reporting of pain can be difficult in populations with communication challenges or atypical sensory processing, such as children with autism spectrum disorder (ASD). Consequently, pain can go untreated. An objective method to identify discomfort would be valuable to individuals unable to express or recognize their own bodily distress. Near-infrared spectroscopy (NIRS) is a brain-imaging modality that is suited for this application. We evaluated the potential of detecting a cortical response to discomfort in the ASD population using NIRS. Using a continuous-wave spectrometer, prefrontal and parietal measures were collected from 15 males with ASD and 7 typically developing (TD) males 10-15 years of age. Participants were exposed to a noxious cold stimulus by immersing their hands in cold water and tepid water as a baseline task. Across all participants, the magnitude and timing of the cold and tepid water-induced brain responses were significantly different (p < 0.001). The effect of the task on the brain response depended on the study group (group x task: p < 0.001), with the ASD group exhibiting a blunted response to the cold stimulus. Findings suggest that NIRS may serve as a tool for objective pain assessment and atypical sensory processing.

Learning, attention, writing, and processing speed in typical children and children with ADHD, autism, anxiety, depression, and oppositional-defiant disorder

Learning, attention, graphomotor, and processing speed scores were analyzed in 149 typical control children and 886 clinical children with normal intelligence. Nonsignificant differences were found between control children and children with anxiety, depression, and oppositional-defiant disorder. Control children performed better than children with ADHD and autism in all areas. Children with ADHD and autism did not differ, except that children with ADHD had greater learning problems. Attention, graphomotor, and speed weaknesses were likely to coexist, the majority of children with autism and ADHD had weaknesses in all three areas, and these scores contributed significantly to the prediction of academic achievement.

Structural and functional MRI- findings in children and adolescents with antisocial behavior

BACKGROUND

The developmental course of children with conduct disorder (CD) is heterogeneous. Especially children who exhibit symptoms early in their lifetimes are characterized by a negative outcome. Neurobiological aspects of CD have been investigated in these children but little is known about structural and functional brain aberrations.

METHODS

We describe the developmental taxonomy of children with CD and focus on those with the early onset subtype. Structural MRI data of these children and antisocial adults are recapitulated. The impact of investigating neurobiological underpinnings of antisocial behavior and how this might contribute to future forensic and psychiatric assessments is discussed. RESULTS/ CONCLUSION: Children display similar structural aberrations of fronto-limbic structures to adults with antisocial behavior, and amygdala dysfunction might be closely related to dysregulated emotions. Though the investigation of biological factors in antisocial subjects has made great progress in recent years, today MRI is still a rather complex, expensive and indistinct method for forensic assessment.

Nuclear Medicine in Pediatric Neurology and Neurosurgery: Epilepsy and Brain Tumors

In pediatric drug-resistant epilepsy, nuclear medicine can provide important additional information in the presurgical localization of the epileptogenic focus. The main modalities used are interictal (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) and ictal regional cerebral perfusion study with single-photon emission computed tomography (SPECT). Nuclear medicine techniques have a sensitivity of approximately 85% to 90% in the localization of an epileptogenic focus in temporal lobe epilepsy; however, in this clinical setting, they are not always clinically indicated because other techniques (eg, icterictal and ictal electroencephalogram, video telemetry, magnetic resonance imaging [MRI]) may be successful in the identification of the epileptogenic focus. Nuclear medicine is very useful when MRI is negative and/or when electroencephalogram and MRI are discordant. A good technique to identify the epileptogenic focus is especially needed in the setting of extra-temporal lobe epilepsy; however, in this context, identification of the epileptogenic focus is more difficult for all techniques and the sensitivity of the isotope techniques is only 50% to 60%. This review article discusses the clinical value of the different techniques in the clinical context; it also gives practical suggestions on how to acquire good ictal SPECT and interictal FDG-PET scans. Nuclear medicine in pediatric brain tumors can help in differentiating tumor recurrence from post-treatment sequelae, in assessing the response to treatment, in directing biopsy, and in planning therapy. Both PET and SPECT tracers can be used. In this review, we discuss the use of the different tracers available in this still very new, but promising, application of radioisotope techniques.

Aufmerksamkeitsstörungen im Kindesalter

Zusammenfassung. Der vorliegende Übersichtsartikel beschäftigt sich mit der Bedeutung der funktionellen Kernspintomographie (fMRT) für diagnostische und therapeutische Aspekte von kindlichen Aufmerksamkeitsstörungen. Nach einer kurzen Einführung in die Methode und ihre Besonderheiten bei der Anwendung im Kindesalter, werden Ergebnisse aus fMRT-Studien bei Kindern mit einem Aufmerksamkeitsdefizit/Hyperaktivitätssyndrom (ADHS) zusammengefasst. Abschließend werden weitergehende Chancen und Nutzen der funktionellen Kernspintomographie für die klinische Praxis und zukünftige Forschungsperspektiven diskutiert.

Bildgebungsbefunde bei Kindern und Jugendlichen mit ADHS, Tic-Störungen und Zwangserkrankungen

Zusammenfassung: ADHS, Tic-Störung, Tourette-Syndrom und Zwangsstörung sind gekennzeichnet durch Defizite in der Handlungskontrolle und treten überzufällig häufig komorbid auf. Es bestehen Hinweise auf eine gemeinsame neurobiologische Basis. Der folgende Übersichtsartikel fasst Ergebnisse aus Bildgebungsstudien zu diesen Störungen im Kindes- und Jugendalter zusammen, wobei strukturelle und funktionelle Befunde durch Magnetresonanztomographie einen Schwerpunkt einnehmen. Übereinstimmend zeigen sich im Vergleich zu gesunden Kontrollen morphologische Veränderungen im Bereich von Basalganglien und präfrontalem Kortex sowie abnorme Aktivierungen in fronto-striatalen Systemen. Vor allem beim ADHS und Tourette-Syndrom werden präfrontale Abweichungen gefunden, die beim letzteren milder ausgeprägt sind und unter Umständen auf Kompensationsmechanismen zurückzuführen sein könnten. Beim ADHS finden sich zusätzlich kleine, globale morphologische Veränderungen im gesamten Kortex und im Zerebellum, beim Tourette-Syndrom werden zudem Auffälligkeiten im okzipitalen Kortex beschrieben. Bei der Zwangserkrankung bestehen weitere strukturelle und funktionelle Aberrationen im Bereich von Amygdala und Thalamus und zudem orbito-frontale Funktionsveränderungen, die beim ADHS eher im ventralen präfrontalen Kortex zu finden sind. Diese Befunde scheinen insgesamt mit Störungen in kortiko-striato-thalamiko-kortikalen Regelkreisen assoziiert zu sein und u. a. in Verbindung mit Dysfunktionen im Bereich der Inhibition von motorischen Reaktionen, impulsiven Handlungen und unerwünschten Gedanken zu stehen. Generell wird die Aussagekraft und Vergleichbarkeit vieler Studien durch kleine und heterogene Gruppen sowie methodische Unterschiede eingeschränkt.

Regional cerebral blood flow in children with ADHD: changes with age

The aim of this study was to investigate the changes in regional cerebral blood flow (rCBF) with age in patients with attention deficit hyperactivity disorder (ADHD). Twenty-nine drug-naive ADHD subjects (24 boys, 5 girls; age 7-13; mean+/-SD=age 9.2+/-2.1) and 12 subjects with epilepsy (all diagnosed as having complex partial seizure, 6 boys, 6 girls; age 7-14; mean+/-SD=8.5+/-2.1) were included in the study. All cases of ADHD were diagnosed according to DSM-IV criteria. Cerebral blood flow was evaluated with Tc-99m-hexamethylpropyleneamine oxime (Tc99m HMPAO) brain single photon emission tomography (SPECT) during standard resting condition in all of the cases. Asymmetry indices for each region of interest were calculated. Absolute rCBF values were normalized as the absolute rCBF values divided by the whole brain absolute value. The prefrontal lobe asymmetry indices were significantly negatively correlated with age in ADHD cases (r=-0.408, P=0.025), which indicated the increased prefrontal rCBF lateralization from the right to the left side with age. When ADHD cases older than 7 years of age were compared with those with epilepsy, the ADHD cases had lower right prefrontal and frontal rCBF and higher left parietal rCBF. The epilepsy group showed no significant correlations between age and asymmetry indices and showed a different developmental trajectory for prefrontal asymmetry and right prefrontal rCBF values. The results indicated that the left hemisphere dominance in the prefrontal cortex significantly increases with age in ADHD cases.