Impaired attention mechanisms in confabulating patients: A VLSM and DWI study.

Attention is one of the most studied cognitive functions in brain-damaged populations or neurological syndromes, as its malfunction can be related to deficits in other higher cognitive functions. In the present study, we aimed at delimiting the attention deficits of a sample of brain-injured patients presenting confabulations by assessing their performance on alertness, spatial orienting, and executive control tasks. Confabulating patients, who present false memories or beliefs without intention to deceive, usually show memory deficits and/or executive dysfunction. However, it is also likely that attention processes may be impaired in patients showing confabulations. Here, we compared confabulating patients' attention performance to a lesion control group and a healthy control group. Confabulating patients' mean overall accuracy was lower than the one of healthy and lesion controls along the three experimental tasks. Importantly, confabulators presented a greater Simon congruency effect than both lesion controls and healthy controls in the presence of predictive spatial cues, besides a lower percentage of hits and longer RTs in the Go-NoGo task, demonstrating deficits in executive control. They also showed a higher reliance on alerting and spatially predictive orienting cues in the context of a deficient performance. Grey and white matter analyses showed that patients' percentage of hits in the Go-NoGo task was related to damage to the right inferior frontal gyrus (pars triangularis and pars opercularis), whereas the integrity of the right inferior fronto-occipital fasciculus was negatively correlated with their alertness effect. These results are consistent with previous literature highlighting an executive dysfunction in confabulating patients, and suggest that some additional forms of attention, such as alertness and spatial orienting, could be selectively impaired in this clinical syndrome.

Conscious perception in patients with prefrontal damage.

We are conscious and verbally report some of the information reaching our senses, although a big amount of information is processed unconsciously. There is no agreement about the neural correlates of consciousness, with low-level theories proposing that neural processing on primary sensory brain regions is the most important neural correlate of consciousness, while high-level theories propose that activity within the fronto-parietal network is the key component of conscious processing (Block, 2009). Contrary to the proposal of high-level theories, patients with prefrontal lobe damage do not present clinical symptoms associated to consciousness deficits. In the present study, we explored the conscious perception of near-threshold stimuli in a group of patients with right prefrontal damage and a group of matched healthy controls. Results demonstrated that perceptual contrast to perceive the near-threshold targets was related to damage to the right dorsolateral prefrontal cortex, and with reduced integrity of the ventral branch of the right superior longitudinal fascicule (SLF III). These results suggest a causal role of the prefrontal lobe in conscious processing.

Resección completa de neurocitoma extraventricular hipervascularizado tras embolización preoperatoria / Complete resection of hypervascularised extraventricular neurocytoma after preoperative embolisation

Una mujer de 13 años de edad presenta clínica de cefalea de 15 días de evolución y solo edema de papila bilateral en la exploración. El estudio inicial de tomografía computarizada y RM mostró una gran masa multiquística frontal izquierda con calcificación rodeada de edema periférico, sangrado intralesional subagudo y múltiples importantes vasos asociados. Se interviene en otro centro, encontrando cavidad con hematoma subagudo que se evacua con múltiples vasos y venas arteriolizadas. Ante la sospecha de malformación arteriovenosa (MAV) a pesar de los hallazgos de la neuroimagen realizada previamente, se deriva a nuestro centro para seguir tratamiento. Realizamos arteriografía, angio-RM y RM con secuencias avanzadas que muestran masa intraaxial hipervascularizada que se emboliza previo a la interviene quirúrgica definitiva con resultado anatomopatológico de neurocitoma extraventricular (NEV). Los NEV son lesiones extremadamente raras que no se han descrito previamente en la literatura como lesiones hipervascularizadas que en nuestro caso requirió la realización de angiografía y embolización previa para su correcto diagnóstico y adecuado manejo

A 13-year-old female arrived at the Emergency Department with a two-week history of headache, and bilateral papilloedema on examination. The initial study with CT and MRI showed a large multicystic left frontal mass with calcification surrounded by peripheral oedema, subacute intralesional bleeding and association of multiple large vessels. She was initially operated on in another centre where a subacute haematoma was found, evacuating to multiple vessels and arteriolised veins. Despite the earlier neuroimaging findings, arteriovenous malformation (AVM) was suspected, so she was referred to our centre for further treatment. We performed angiography, MR angiography and MRI with advanced sequences, diagnosing a highly vascularised intra-axial tumour which was embolised. The patient was then definitively operated on, with the resulting finding of extraventricular neurocytoma (EVN). EVN are extremely rare lesions, not previously described in the literature as hypervascularised lesions, which in our case required prior angiography and embolisation for proper diagnosis and adequate management

Complete resection of hypervascularised extraventricular neurocytoma after preoperative embolisation. / Resección completa de neurocitoma extraventricular hipervascularizado tras embolización preoperatoria.

A 13-year-old female arrived at the Emergency Department with a two-week history of headache, and bilateral papilloedema on examination. The initial study with CT and MRI showed a large multicystic left frontal mass with calcification surrounded by peripheral oedema, subacute intralesional bleeding and association of multiple large vessels. She was initially operated on in another centre where a subacute haematoma was found, evacuating to multiple vessels and arteriolised veins. Despite the earlier neuroimaging findings, arteriovenous malformation (AVM) was suspected, so she was referred to our centre for further treatment. We performed angiography, MR angiography and MRI with advanced sequences, diagnosing a highly vascularised intra-axial tumour which was embolised. The patient was then definitively operated on, with the resulting finding of extraventricular neurocytoma (EVN). EVN are extremely rare lesions, not previously described in the literature as hypervascularised lesions, which in our case required prior angiography and embolisation for proper diagnosis and adequate management.

Hipertensión intracraneal idiopática y fístula espontánea de líquido cefalorraquídeo. Utilidad de la monitorización de la presión intracraneal / Idiopathic intracranial hypertension and spontaneous cerebrospinal fluid fistula. Usefulness of intracranial pressure monitoring

Las fístulas espontáneas de líquido cefalorraquídeo (LCR) constituyen una entidad clínica relativamente frecuente en la práctica neuroquirúrgica. El tratamiento quirúrgico va encaminado al cierre del defecto y el porcentaje de recurrencias no es bajo. La asociación de fístula espontánea de LCR e hipertensión intracraneal idiopática (HII) es frecuente y posiblemente sea la causa de esta baja tasa de éxito. La semiología clínica de la HII asociada a la fístula espontánea de LCR no es típica, lo que hace que su diagnóstico pase a menudo desapercibido. La monitorización continua de la presión intracraneal permite diagnosticar situaciones de hipertensión intracraneal crónica en estos pacientes, por lo que su utilización es de extraordinaria utilidad a la hora de plantear alternativas terapéuticas

Spontaneous cerebrospinal fluid (CSF) fistulas are rather common in daily practice. The aim of the surgical treatment is closure of the leak, but recurrences are quite frequent. The association between spontaneous CSF fistulas and idiopathic intracranial hypertension (IIH) is not uncommon, and this is probably the cause of the low rate of success of the surgical treatment. Symptoms of IIH associated with spontaneous CSF fistula are atypical, and diagnosis is often missed. Continuous intracranial pressure monitoring is very useful in the diagnosis of chronic IIH and in patients with spontaneous CSF fistula, as it helps in making decisions on the treatment of these patients

[Idiopathic intracranial hypertension and spontaneous cerebrospinal fluid fistula. Usefulness of intracranial pressure monitoring]. / Hipertensión intracraneal idiopática y fístula espontánea de líquido cefalorraquídeo. Utilidad de la monitorización de la presión intracraneal.

Spontaneous cerebrospinal fluid (CSF) fistulas are rather common in daily practice. The aim of the surgical treatment is closure of the leak, but recurrences are quite frequent. The association between spontaneous CSF fistulas and idiopathic intracranial hypertension (IIH) is not uncommon, and this is probably the cause of the low rate of success of the surgical treatment. Symptoms of IIH associated with spontaneous CSF fistula are atypical, and diagnosis is often missed. Continuous intracranial pressure monitoring is very useful in the diagnosis of chronic IIH and in patients with spontaneous CSF fistula, as it helps in making decisions on the treatment of these patients.

In vivo long-term magnetic resonance imaging activity of ferritin-based magnetic nanoparticles versus a standard contrast agent.

New long-circulating maghemite nanoparticles of 4 and 6 nm, coated with an apoferritin protein capsid, exhibit useful properties to act as magnetic resonance imaging (MRI) contrast agents. A full in vivo study of the so-called apomaghemites reveals that their long-term MRI properties are better than those of a standard superparamagnetic iron oxide (SPIO) widely used in biomedical applications. The biodistribution of apomaghemites and standard SPIO was investigated by MRI in mice at two different concentrations, 6 and 2.5 mg of Fe·kg(-1), over 60 days. Significant differences are found at low dose (2.5 mg of Fe·kg(-1)). Thus, whereas apomaghemites are active for MR bioimaging of liver for 45 days, standard SPIO is not effective beyond 7 days. On the basis of our data, we may concluded that apomaghemites can act as new long-term MRI liver contrast agents, allowing first the diagnosis of a liver pathology and then monitoring after treatment without the need for a second injection.

CNK/T-cell brain lymphoma associated with Epstein-Barr virus in a patient with AIDS.

We report a case of extranodal NK/T-cell lymphoma, nasal type, with exclusive cerebral localization in a patient with AIDS. The patient presented with neurological alterations, fever and convulsions, so the initial presumptive diagnosis was an opportunistic brain infection. MRI showed a left parietal necrotic lesion and a stereotactic brain biopsy was performed for pathological, microbiological and molecular studies. Histological sections showed an angiocentric and angiodestructive growth pattern and the immunophenotype of this tumor was CD56+, CD45+, CD3+ (cytoplasmic), Granzyme B+ and Perforin+. All the microbiological studies such as bacterial, fungi, micobacteria, Toxoplasma gondii and Cryptococcus determination were negatives. A PCR study with primer specific for EBV viral genome of Bam-Hi-w system was positive. Also, a rearrangement study showed T-cell gene rearrangement with monoclonal appearance. A diagnosis of extranodal NK/T-cell lymphoma was made and the patient died a few days later. This case represents a very rare example of NK/T-cell lymphoma of the brain in a patient with AIDS. The diagnosis of this kind of lymphomas requires a multimodality approach correlating clinical, morphological, immunophenotypic and molecular data.