Poor stimulus discriminability as a common neuropsychological deficit between ADHD and reading ability in young children: a moderated mediation model.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is frequently associated with poorer reading ability; however, the specific neuropsychological domains linking this co-occurrence remain unclear. This study evaluates information-processing characteristics as possible neuropsychological links between ADHD symptoms and RA in a community-based sample of children and early adolescents with normal IQ (⩾70). METHOD: The participants (n = 1857, aged 6-15 years, 47% female) were evaluated for reading ability (reading single words aloud) and information processing [stimulus discriminability in the two-choice reaction-time task estimated using diffusion models]. ADHD symptoms were ascertained through informant (parent) report using the Development and Well-Being Assessment (DAWBA). Verbal working memory (VWM; digit span backwards), visuospatial working memory (VSWM, Corsi Blocks backwards), sex, socioeconomic status, and IQ were included as covariates. RESULTS: In a moderated mediation model, stimulus discriminability mediated the effect of ADHD on reading ability. This indirect effect was moderated by age such that a larger effect was seen among younger children. CONCLUSION: The findings support the hypothesis that ADHD and reading ability are linked among young children via a neuropsychological deficit related to stimulus discriminability. Early interventions targeting stimulus discriminability might improve symptoms of inattention/hyperactivity and reading ability.

Coordinated brain development: exploring the synchrony between changes in grey and white matter during childhood maturation.

Brain development during childhood and early adolescence is characterized by global changes in brain architecture. Neuroimaging studies have revealed overall decreases in cortical thickness (CT) and increases in fractional anisotropy (FA). Furthermore, previous studies have shown that certain cortical regions display coordinated growth during development. However, there is significant heterogeneity in the timing and speed of these developmental transformations, and it is still unclear whether white and grey matter changes are co-localized. In this multimodal neuroimaging study, we investigated the relationship between grey and white matter developmental changes and asynchronous maturation within brain regions in 249 normally developing children between the ages 7-14. We used structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to analyze CT and FA, respectively, as well as their covariance across development. Consistent with previous studies, we observed overall cortical thinning with age, which was accompanied by increased FA. We then compared the coordinated development of grey and white matter as indexed by covariance measures. Covariance between grey matter regions and the microstructure of white matter tracts connecting those regions were highly similar, suggesting that coordinated changes in the cortex were mirrored by coordinated changes in their respective tracts. Examining within-brain divergent trajectories, we found significant structural decoupling (decreased covariance) between several brain regions and tracts in the 9- to 11-year-old group, particularly involving the forceps minor and the regions that it connects to. We argue that this decoupling could reflect a developmental pattern within the prefrontal region in 9- and 11-year-old children, possibly related to the significant changes in cognitive control observed at this age.

Cortical thinning of the right anterior cingulate cortex in spider phobia: a magnetic resonance imaging and spectroscopy study.

There a lack of consistent neuroimaging data on specific phobia (SP) and a need to assess volumetric and metabolic differences in structures implicated in this condition. The aim of this study is investigate possible metabolic (via (1)H MRS) and cortical thickness abnormalities in spider-phobic patients compared to healthy volunteers. Participants were recruited via public advertisement and underwent clinical evaluations and MRI scans. The study started in 2010 and the investigators involved were not blind in respect to patient groupings. The study was conducted at the Ribeirão Preto Medical School University Hospital of the University of São Paulo, Brazil. Patients with spider phobia (n=19) were matched to 17 healthy volunteers with respect to age, education and socio-economic status. The spider SP group fulfilled the diagnostic criteria for spider phobia according to the Structured Clinical Interview for DSM-IV. None of the participants had a history of neurological, psychiatric or other relevant organic diseases, use of prescribed psychotropic medication or substance abuse. All imaging and spectroscopy data were collected with a 3 T MRI scanner equipped with 25 mT gradient coils in 30-minute scans. The Freesurfer image analysis package and LC Model software were used to analyze data. The hypothesis being tested was formulated before the data collection (neural correlates of SP would include the amygdala, insula, anterior cingulate gyrus and others). The results indicated the absence of metabolic alterations, but thinning of the right anterior cingulate cortex (ACC) in the SP group when compared to the healthy control group (mean cortical thickness±SD: SP=2.11±0.45 mm; HC=2.16±0.42 mm; t (34)=3.19, p=0.001 [-35.45, 71.00, -23.82]). In spectroscopy, the ratios between N-acetylaspartate and creatine and choline levels were measured. No significant effect or correlation was found between MRS metabolites and scores in the Spider Phobia Questionnaire and Beck Anxiety Inventory (p>0.05). The ACC is known to be related to the cognitive processing of fear and anxiety and to be linked with the conditioning circuit. The MRS findings are preliminary and need more studies. The finding of reduced ACC thickness in SP is in agreement with evidence from previous functional neuroimaging studies and highlights the importance of this brain area in the pathophysiology of SP.

Is cerebellar volume related to bipolar disorder?

BACKGROUND: Recent data suggest that cerebellum influences emotion modulation in humans. The findings of cerebellar abnormalities in bipolar disorder (BD) are especially intriguing given the link between the cerebellum emotional and behavioral regulation. The purpose of this study was to evaluate cerebellar volume in patients with euthymic BD type I compared to controls. Moreover, we investigated the possible relationship between cerebellar volume and suicidal behavior. METHODS: Forty-patients with euthymic BD type I, 20 with and 20 without history of suicide attempt, and 22 healthy controls underwent an MRI scan. The participants were interviewed using the Structured Clinical Interview with the DSM-IV axis I (SCID-I), the Hamilton Depression Rating Scale (HDRS), the Young Mania Rating Scale (YMRS) and the Barratt Impulsiveness Scale (BIS-11). RESULTS: Groups were age, gender and years of schooling-matched. The left cerebellum (p=0.02), right cerebellum (p=0.02) and vermis (p<0.01) were significantly smaller in the BD group; however, there were no volumetric differences between the BD subjects with and without suicidal attempt. There was no correlation between cerebellar measurements and clinical variables. LIMITATIONS: The main strength is that our sample consisted of patients with euthymic BD type I without any comorbidities, however, these results cannot establish causality as the cross-sectional nature of the study. CONCLUSIONS: Our findings suggest that the reduction in cerebellar volumes observed in BD type I might be a trait-related characteristic of this disorder. Additional studies with larger samples and subtypes of this heterogeneous disorder are warranted to determine the possible specificity of this cerebellar finding.

High CSF transforming growth factor beta levels after subarachnoid haemorrhage: association with chronic communicating hydrocephalus.

BACKGROUND: Chronic communicating hydrocephalus is a common sequela of subarachnoid haemorrhage and develops when the flow and drainage of CSF are impaired after fibrosis in the subarachnoid space. Released by platelets into the CSF after subarachnoid haemorrhage, transforming growth factor (TGF)beta1/beta2 are potent fibrogenic agents that may promote post-haemorrhagic fibrosis and chronic communicating hydrocephalus. METHODS: Temporal changes in total (latent plus active) TGFbeta1/beta2 CSF levels of post-haemorrhage patients developing acute hydrocephalus were measured using ELISA to discover if titres were higher in patients that subsequently developed chronic communicating hydrocephalus, compared with those that did not. RESULTS: Mean (SD) CSF levels of total TGFbeta1 were 97 (42) pg/ml and total TGFbeta2 were 395 (39) pg/ml in control patients with (non-haemorrhagic) hydrocephalus. For days 1-5 post-subarachnoid haemorrhage (dph), levels of 1427 (242) pg/ml and 976 (191) pg/ml were seen for total TGFbeta1 and TGFbeta2, respectively. Beyond 5 dph, total TGFbeta1/beta2 levels declined but remained significantly elevated (p<0.01) above control patient values for at least 19 dph. Haemorrhagic patients that went on to develop chronic communicating hydrocephalus had significantly higher levels of total TGFbeta1 (p<0.01) and TGFbeta2 (p<0.05) between 1 and 9 dph, compared with those of haemorrhagic patients that did not. CONCLUSIONS: Acutely measured levels of TGFbeta1/beta2 in the CSF of patients with subarachnoid haemorrhage are thus potential prognostic biomarkers for the subsequent development of chronic communicating hydrocephalus, indicating likely dependency on CSF shunting.

Cage versus tricortical graft for cervical interbody fusion. A prospective randomised study.

We conducted a prospective, randomised study of 42 cervical interbody fusions undertaken with either an autologous tricortical graft or a cage. The factors assessed in the two groups were: (1) time taken to achieve fusion; (2) neck disability index; (3) pain score; (4) interbody height ratio; (5) interbody angle and (6) the influence of smoking on fusion. No statistical difference was seen in the time taken to achieve fusion, neck disability index, interbody height ratio, or interbody angles. Smoking did not have any effect on the fusion process. The pain score was significantly lower in the tricortical graft group at six months. We conclude that both methods of fusion give similar results, although tricortical graft fusion is cheaper than cage fusion, and is more effective in reducing the pain score.

Clear cell sarcoma (malignant melanoma of soft parts) presenting as cervical myelopathy.

A 47-year-old woman presented with a 2 year history of progressive cervical myelopathy. MRI revealed a lesion anterior to the cord at the level of C1/C2. This was excised and found to be a clear cell sarcoma, a tumour not previously reported at this site.

Transforming growth factor-beta1 in the cerebrospinal fluid of patients with subarachnoid hemorrhage: titers derived from exogenous and endogenous sources.

Transforming growth factor-beta1 (TGF-beta1) is a fibrogenic cytokine that is involved in postinjury repair and is implicated in the etiology of postsubarachnoid hemorrhage (SAH) chronic communicating hydrocephalus. TGF-beta1 was measured by enzyme-linked immunosorbant assay (ELISA) in sequential samples of cerebrospinal fluid (CSF) in 11 patients with hydrocephalus after SAH; levels were seen to be biphasically elevated and sources were investigated. TGF-beta1 levels were compared with albumin levels that estimated CSF blood content. Control samples from nonhemorrhagic hydrocephalics were tested similarly. Mean total TGF-beta1 levels were elevated to 4400+/-3435 (+/-SD) pg/mL greater than control levels of 97+/-42 at 1 to 2 days posthemorrhage. Thereafter, levels fell to 714+/-401 by 5 to 6 days posthemorrhage, then rose to a second peak of 1667+/-774 at 9 to 10 days posthemorrhage, remaining significantly increased until 19 days posthemorrhage (P = 0.007). The first peak probably derived from extravasated platelets and correlated with increased albumin levels in the CSF. The second TGF-beta1 peak rose greater than CSF albumin levels that had stabilized at this time, and thus was attributed to a tissue-specific response rather than a re-bleed. TGF-beta1 was detected in the choroid secretory epithelium from controls, but levels were greater in SAH patients at 10 to 12 days posthemorrhage. The authors conclude that the elevated levels of TGF-beta1 in CSF after SAH are derived initially from blood and later from endogenous sources such as the choroid plexus.

Anatomic variations of anterior cerebral artery cortical branches.

The anterior cerebral artery (ACA) is a major vessel responsible for the blood supply to the interhemispheric region. The ACA segment after the anterior communicating artery (AComA) origin is called the distal ACA and has central and cortical branches. The cortical branches are distributed in the different regions of the orbital and medial part of the brain. The objects of this study are the anatomical variations found in the distal ACA. In 76 hemispheres the ACA distal branches were injected with latex and dissected under microscope magnification. Vessel diameters and distances between vessel origins and anterior communicating artery were recorded and analyzed. Microsurgical dissection was carried out to demonstrate anatomic variations of these vessels. Average diameter of ACA at origin was 2.61 +/- 0.34 mm and average diameter of cortical branches diameter ranged from 0.79 +/- 0.27 mm to 1.84 +/- 0.3 mm. Distances between vessel origin and AComA ranged from 7.68 +/- 3.91 mm (orbitofrontal) to 112.6 +/- 11.63 mm (inferior internal parietal). This study found anatomical variations: a single (azygos) ACA was present in one case and three in three cases. Crossing branches of the distal ACA to the contralateral hemisphere were present in 26% of the cases. In some cases a single ACA may supply the posterior hemispheric region through crossing branches. This calls attention to potential bilateral brain infarcts due to a single unilateral ACA occlusion.

Harvesting and preparation of cadaveric osseoligamentous lower cervical spine (C2-C7) for biomechanical testing.

Cadaveric osseoligamentous lower cervical spines (C2-C7) are often used in the investigation of spinal biomechanics in vitro. Surprisingly, however, the techniques of harvesting at postmortem and preparation of cadaveric osseoligamentous lower cervical spine for biomechanical testing have not been described in detail. We describe a simple and effective method that can be readily integrated into the routine autopsy procedure. Points on the avoidance of disfiguring the cadaver and damaging the spinal osseoligamentous structures are highlighted.

Central neurocytoma: a correlative clinicopathologic and radiologic analysis.

BACKGROUND: Central neurocytoma was described as a well differentiated tumor of neuronal origin, distinct from ganglion cell tumors and neuroblastoma. An initially perceived benign biologic behavior has been questioned by subsequent reports of anaplastic and recurrent tumors. We report six cases of central neurocytoma, with variable clinical and pathologic features that stimulate discussion on the management of these tumors. METHODS: Of the 95 oligodendrogliomas treated in our institution in the last 40 years, three tumors were reclassified as central neurocytomas on histologic reappraisal. Three additional cases prospectively diagnosed as central neurocytomas are reported. The clinical, pathologic, and radiologic features are reviewed. RESULTS: Early recurrence, not related to malignant histologic features, was noted in two patients who had not received postoperative radiotherapy. Anaplastic histologic changes were not accompanied by malignant biologic behavior in another patient. Neither patient with recurrent tumor was controlled by radiotherapy alone. Chemotherapy with carboplatin reduced tumor size temporarily in one of these patients. CONCLUSION: An entirely benign nature for this tumor is questioned and it appears that there may be malignant variants. Surgery should aim for maximum possible excision, as the location of the tumor allows. The role of postoperative radiotherapy remains controversial and may be considered in cases of subtotal excision of tumors with anaplastic histologic features. Chemotherapy may be of benefit in cases recurring despite surgery and radiotherapy.

Middle cerebral artery revascularization. Anatomical studies and considerations on the anastomosis site.

In the surgical management of skull base lesions and vascular diseases such as giant aneurysms, involvement of the internal carotid artery may require the resection or the occlusion of the vessel. The anastomosis of the external carotid artery and the middle cerebral artery with venous graft may be indicated to re-establish the blood flow. To determine the best suture site in the middle cerebral artery, an anatomical study was carried out. Fourteen cerebral hemispheres were analysed after the injection of red latex into the internal carotid artery. The superior and inferior trunk of the main division of the middle cerebral artery have more than 2 mm of diameter. They are superficial allowing an anastomosis using a venous graft. The superior trunk has a disadvantage, it gives rise to branches for the precentral and post-central giri. The anastomosis with the inferior trunk presents lower risk of neurological deficit even though the angular artery originates from it.

Spinal ependymomas--the value of postoperative radiotherapy for residual disease control.

Spinal ependymomas are rare intramedullary tumours, usually with a benign biological nature. They have, however, a known potential for recurrence and metastatic spread through the CSF pathways. Traditionally, radiotherapy has been employed as an adjuvant to surgery. Recently, however, this view has been increasingly questioned. Thirty-eight adult patients operated in the West Midlands between 1956 and 1994 were reviewed. Mean age at presentation was 37.8 years. Of all tumours 45% (17) were situated in the conus/cauda equina region, 26% (10) in the thoracic and 29% (11) in the cervical region. All patients underwent surgery as primary treatment. Postoperative mortality was 2.6% (one patient). Complete macroscopic excision of their tumours was performed in 14 patients; of these three received postoperative radiotherapy. Subtotal excision was performed in 18 patients, seven receiving adjuvant radiotherapy. Decompressive laminectomy and biopsy was performed in five patients with either no radiotherapy in one, radiotherapy in three or radiotherapy and chemotherapy in one. The overall survival rate was 87% at 5 years and 73% at 10 years for the whole series. In patients treated after the 1970s, the cumulative 10-year survival was 95%. Patients over the age of 40 years at diagnosis had a 10-year survival of 61% compared to 78% of those under the age of 40. Intramedullary tumours had a worse outcome with 68% survival at 10 years, compared to 89% of tumours at the cauda equina. Total excision carried 86% survival, subtotal excision 80% and biopsy only 25% at 10 years. In those patients treated by administration of postoperative radiotherapy the 10-year survival was 48%, compared to 96% in those in whom radiotherapy was not given postoperatively. Analysis of the recurrence and survival rates demonstrated that radiotherapy did not confer any significant protection against recurrence or disease progression. Whilst complete excision offers the maximal potential for cure, an expectant policy with possible repeat surgery may be appropriate when total excision is not achieved. The main conclusion to be drawn is that a randomized controlled trial of the value of adjuvant radiotherapy is greatly needed.

Missed cervical spine injury following barflying.

The case is reported of a young woman who suffered a wedge fracture of C7 due to axial loading with a flexed spine, in an injury caused by barfly jumping. The fracture was unstable and required surgical stabilisation. In this case the seriousness of the injury was not realised at first because neck radiographs were not taken at her initial assessment in accident and emergency.

Neural injury repair: hope for the future as barriers to effective CNS regeneration become clearer.

In this review the author outlines the early history of clinical and scientific research upon the inability of the CNS in man to successfully regenerate following injury. As we proceed into the 21st Century we have gained a far greater understanding of the molecular biology, pathology and other factors that lead to the adult CNS being non-supportive and indeed actively inhibitory to axonal regrowth. On the basis of these recent advances in knowledge, the author outlines possible therapeutic approaches that may enable more effective CNS regeneration to be accomplished in the future.

Laser-assisted flexible endoscopic fenestration of giant cyst of the septum pellucidum.

The use of the flexible neuroendoscope and laser fenestration in the surgical management of a symptomatic cyst of cavum septum pellucidum is reported. Successful communication was established between the cyst cavity and the lateral ventricles using this technique. Satisfactory clinical and radiological improvement as seen on MRI confirmed the operative success.

Central neurocytoma without intraventricular extension.

A case of central neurocytoma is reported, presenting as a tumor of the occipital lobe, closely related to the ependyma of the occipital horn of the lateral ventricle but not actually invading it. This is a distinctly uncommon location, and only four tumors have been reported so far in a lobar position, without an intraventricular component. The case broadens our knowledge of this recently described tumor and gives an opportunity for discussion of the role of radiotherapy in its management, which currently remains controversial.

Lateral parascapular extrapleural approach for single-stage excision of dumb-bell neurofibroma.

An excision of a T1 dumb-bell neurofibroma via a single-stage lateral parascapular extrapleural approach is described. The different surgical approaches that can be used to approach dumb-bell tumours are reviewed, together with the relevant literature.