Howard Ring

A prospective study of the early postsurgical psychiatric associations of epilepsy surgery

OBJECTIVES To examine prospectively the frequency and nature of psychiatric symptoms seen in patients during the first three months after temporal lobe surgery for chronic intractable epilepsy and in addition to study the relation between presurgical mental state, laterality of surgery, and postsurgical seizure and psychiatric course. METHOD A consecutive series of 60 patients being assessed for temporal lobe surgery for intractable epilepsy were studied. They were interviewed before surgery and at six weeks and again at three months after operation. RESULTS At six weeks after surgery half of those with no psychopathology preoperatively had developed symptoms of anxiety or depression and 45% of all patients were noted to have increased emotional lability. By three months after surgery emotional lability and anxiety symptoms had diminished whereas depressive states tended to persist. Patients with a left hemispheric focus were more likely to experience persisting anxiety. CONCLUSION The early months after surgery for epilepsy are characterised by the relatively common presence of psychiatric symptoms. It is proposed that presurgical and early postsurgical neuropsychiatric involvement in programmes of surgery for epilepsy will help to improve the quality of the treatment package offered to patients.

Atypical EEG complexity in autism spectrum conditions: a multiscale entropy analysis.

OBJECTIVE Intrinsic complexity subserves adaptability in biological systems. One recently developed measure of intrinsic complexity of biological systems is multiscale entropy (MSE). Autism spectrum conditions (ASC) have been described in terms of reduced adaptability at a behavioural level and by patterns of atypical connectivity at a neural level. Based on these observations we aimed to test the hypothesis that adults with ASC would show atypical intrinsic complexity of brain activity as indexed by MSE analysis of electroencephalographic (EEG) activity. METHODS We used MSE to assess the complexity of EEG data recorded from 15 participants with ASC and 15 typical controls, during a face and chair matching task. RESULTS Results demonstrate a reduction of EEG signal complexity in the ASC group, compared to typical controls, over temporo-parietal and occipital regions. No significant differences in EEG power spectra were observed between groups, indicating that changes in complexity values are not a reflection of changes in EEG power spectra. CONCLUSIONS The results are consistent with a model of atypical neural integrative capacity in people with ASC. SIGNIFICANCE Results suggest that EEG complexity, as indexed by MSE measures, may also be a marker for disturbances in task-specific processing of information in people with autism.

Measuring autistic traits in the general population: a systematic review of the Autism-Spectrum Quotient (AQ) in a nonclinical population sample of 6,900 typical adult males and females

[This corrects the article DOI: 10.1186/2040-2392-6-2.].

Task-related functional connectivity in autism spectrum conditions: an EEG study using wavelet transform coherence

BackgroundAutism Spectrum Conditions (ASC) are a set of pervasive neurodevelopmental conditions characterized by a wide range of lifelong signs and symptoms. Recent explanatory models of autism propose abnormal neural connectivity and are supported by studies showing decreased interhemispheric coherence in individuals with ASC. The first aim of this study was to test the hypothesis of reduced interhemispheric coherence in ASC, and secondly to investigate specific effects of task performance on interhemispheric coherence in ASC.MethodsWe analyzed electroencephalography (EEG) data from 15 participants with ASC and 15 typical controls, using Wavelet Transform Coherence (WTC) to calculate interhemispheric coherence during face and chair matching tasks, for EEG frequencies from 5 to 40 Hz and during the first 400 ms post-stimulus onset.ResultsResults demonstrate a reduction of interhemispheric coherence in the ASC group, relative to the control group, in both tasks and for all electrode pairs studied. For both tasks, group differences were generally observed after around 150 ms and at frequencies lower than 13 Hz. Regarding within-group task comparisons, while the control group presented differences in interhemispheric coherence between faces and chairs tasks at various electrode pairs (FT7-FT8, TP7-TP8, P7-P8), such differences were only seen for one electrode pair in the ASC group (T7-T8). No significant differences in EEG power spectra were observed between groups.ConclusionsInterhemispheric coherence is reduced in people with ASC, in a time and frequency specific manner, during visual perception and categorization of both social and inanimate stimuli and this reduction in coherence is widely dispersed across the brain.Results of within-group task comparisons may reflect an impairment in task differentiation in people with ASC relative to typically developing individuals.Overall, the results of this research support the value of WTC in examining the time-frequency microstructure of task-related interhemispheric EEG coherence in people with ASC.

Psychiatric profiles and patterns of cerebral blood flow in focal epilepsy: interactions between depression, obsessionality, and perfusion related to the laterality of the epilepsy.

OBJECTIVES: In a study of patients with focal epilepsy the hypothesis was explored that different measurements of psychopathology are related to specific distributions of cerebral perfusion. METHODS: Forty patients had SPECT performed with (99m)Tc-HMPAO. In addition, patients received a psychiatric evaluation with the following psychiatric questionnaires: the Beck depression inventory, the Leyton obsessionality inventory, the Bear-Fedio questionnaire, and the social stress and support interview. Patients were analysed in two groups according to the laterality of the epilepsy. Nine patients were excluded based on poor quality scans (n = 1), unlateralised epilepsy (n = 4), and left or ambidextrous handedness (n = 4). RESULTS: There were no overall differences between the left and right epilepsy groups on measures of psychopathology. Associations were found between scores on some of the rating scales and regional cerebral blood flow. Specifically, for patients with left sided epilepsy, higher scores on the Beck depression inventory were associated with lower contralateral temporal and bilateral frontal perfusion, and higher occipital perfusion. For patients with right sided epilepsy higher scores on the Leyton obsessionality inventory were associated with increased perfusion in ipsilateral temporal, thalamic, and basal ganglia regions and bilateral frontal regions. CONCLUSION: The results do not support the notion that lateralised epileptogenic lesions are associated with different levels of depression, obsessionality, or personality traits. They support the view that certain psychopathological symptom patterns are related to specific regional dysfunctions depending on the laterality of a hemispheric lesion.

Cerebral blood flow abnormalities in adults with infantile autism.

Stuctural brain abnormalities have recently been discovered using magnetic resonance imaging in infantile autism, a neurodevelopmental disorder of unknown etiology. However, functional neuroimaging studies in autism using positron emission tomography have had conflicting results and have not explained how the known structural brain abnormalities in autism act in a functioning brain to produce autistic behavior. Using a new technology, highresolution brain single photon emission tomography, we studied and scanned four young adults with infantile autism and four age-matched controls using the labeled ligand 99mTc-D,Lhexamethyl- propylene amine oxime (99mTc-HMPAO). Total brain perfusion was significantly decreased in autism subjects (range, 58% to 72% of controls, p≤.02). In addition to the globally decreased perfusion, the autism group also had regionally decreased flow in the right lateral temporal and right, left, and midfrontal lobes compared with controls (p≤.02, Mann- Whitney t-test).

Dopamine transporter binding in Gilles de la Tourette syndrome: a [123I]FP-CIT/SPECT study.

Objective:  To investigate dopamine transporter binding in Gilles de la Tourette syndrome (GTS) with SPECT and [123I]FP‐CIT.

A SPECT study of the effect of vagal nerve stimulation on thalamic activity in patients with epilepsy

The mechanism by which vagal nerve stimulation (VNS) exerts an anticonvulsant effect in humans is unknown. This study used (99m)Tc-HMPAO single photon emission tomography (SPECT) to examine the effects of VNS on regional cerebral activity in thalamic and insular regions. Seven subjects with epilepsy who had been receiving vagal nerve stimulation for at least 6 months underwent SPECT scanning with simultaneous scalp electroencephalographic (EEG) recording. Subjects were studied in two states; during VNS activity and during a comparison condition of VNS inactivity. A region of interest analysis demonstrated that rapid cycling stimulation (7 seconds on, 12 seconds off) was associated with relatively decreased activity in left and right medial thalamic regions. No systematic stimulation-related changes were observed on visual or spectral analysis of EEG data. The thalamus is involved in modulation of ongoing cortical EEG activity in animals. Our results support the hypothesis that VNS may exert an antiepileptic action by an effect on thalamic activity.

Neuroactivation and neuroimaging with SPET

This book describes the application of single photon emission tomography (SPET) to neuroactivation imaging in particular and neuroimaging in general. Protocols for SPET, neuroactivation and neuroimaging are described in detail and results are given and discussed on the basis of clinical material and case histories. Normal functional anatomy is correlated with data from MRI. High resolution cerebral blood flow (CBF) imaging is described with the use of SPET technology. Split dose CBF imaging is also mentioned, for activation studies in a variety of normal and diseased states which include the dementias (AIDS, Alzheimers disease and multi-infarction dementia), cerebrovascular disease, depression, schizophrenia, obsessive compulsive disorders, movement disorders (Parkinsons disease, Gilles de la Tourette syndrome, Huntingdons chorea, Sydenhams chorea), epilepsy and tumours. Examples of motor, frontal and visual activation studies are also given.

Elevated frontal cerebral blood flow in Gilles de la Tourette syndrome: A 99Tcm-HMPAO SPECT study

Case reports, numerous brain imaging studies, and certain disease states suggest that the orbital frontal cortex and the striatum are dysfunctional in obsessive-compulsive disorder (OCD). Interest has also grown recently concerning the genetic, neuroanatomic, and clinical links between OCD, chronic motor tics, and Gilles de la Tourette Syndrome (GTS). To test the hypothesis of possible orbito-frontal/basal ganglia dysfunction in GTS, similar to OCD, we studied 20 unmedicated GTS subjects, 10 of whom also had comorbid OCD (GTS/OCD), and 8 control subjects. The subjects were examined with high-resolution single photon emission computed tomography (SPECT) and the labeled regional cerebral blood flow (rCBF) ligand technetium-99m-d,l-hexamethyl-propylene amine oxime (99Tcm-HMPAO). As a group, GTS subjects showed significantly elevated right frontal/visual cortex activity (mean = 0.879, SD = 0.107) compared with control subjects (mean = 0.798, SD = 0.049). A subanalysis comparing simple GTS versus GTS with comorbid OCD failed to reveal significant differences in regional flow.