P300 in mesial temporal lobe epilepsy and its correlation with cognition - A MEG based prospective case-control study.

PURPOSE: To assess the role of P300 in patients with temporal lobe epilepsy (TLE) with unilateral hippocampal sclerosis (HS) using magnetoencephalography (MEG) based auditory and visual oddball tasks, and to assess its correlation with neuropsychological tests. METHODS: Thirty-patients (M:F-17:13, onset-11.77 ±â€¯8.75 years, duration-16.10 ±â€¯9.61 years) with TLE-HS (Left:15, Right:15) and fifteen-healthy age, gender and years of education matched controls (M:F-10:5, age-28.13 ±â€¯4.76 years) underwent auditory and visual oddball tasks in MEG and cognition assessment using Indian Council of Medical Research (ICMR)-cognitive test battery. Independent component analysis (ICA) was applied to the magnetic evoked field responses for the detection of the P300 component. Source localization of P300 was performed with Classical LORETA Analysis Recursively Applied (CLARA). The latency and amplitude of P300 were estimated and subsequently correlated with cognitive scores. RESULTS: The visual P300 amplitude in the TLE group was lower when compared to the control group. In subgroup comparison (controls vs. right HS vs. left HS), visual P300 amplitudes were lower in the right HS group compared to both left HS and control groups (p-value = 0.014). On the other hand, no significant difference for auditory P300 latency or amplitude was noted between patients and controls as well as between subgroups. A negative correlation found between the MEG visual P300 amplitude and Indian Trial Making Test (TMT)-B duration in the patient group. CONCLUSION: Patients with TLE-HS have decreased visual-P300 amplitude. A significant correlation found between visual P300 amplitude and cognitive tests of visuospatial attention and working memory. Overall, MEG based visual P300 amplitude can be further explored with large sample size studies to establish as a complementary objective test for cognitive assessment in TLE.

Pre-operative and post-operative cognitive deficits in patients with supratentorial meningiomas.

OBJECTIVES: Cognitive deficits caused by extra-axial benign brain tumors like meningiomas and the course of these deficits after surgery is not well known. The aim of the study is to assess the pre-operative and post-operative cognitive functions in patients with meningiomas in the supratentorial compartment. MATERIALS AND METHODS: In this prospective study, patients with clinico-radiological diagnosis of supratentorial meningioma, operated upon and later confirmed by histopathological examination, were included. The patients were evaluated for cognitive deficits before and after surgery. The various clinical and radiological factors influencing the cognitive status were evaluated. RESULTS: A total of 57 patients were enrolled into the study. Out of 57, 22 were males and 35 were females. The frontal group had 22 patients, the parietal group had 10 patients, the temporal group had 10 patients, the occipital group had 6 patients, and the suprasellar group had 9 patients. Meningiomas, although extra-axial, caused significant cognitive deficits in 42 patients (73.7%). The highest frequency of cognitive deficits is seen in the frontal and temporal group of meningiomas (90% each). Frontal meningiomas with volume greater than 35 cc and peritumoral edema greater than 40 cc caused a higher frequency of cognitive deficits. Also, patients with raised ICP had significant cognitive deficits. Postoperatively there was a significant improvement in the cognitive functions in the frontal and temporal groups. CONCLUSION: Meningiomas cause cognitive deficits in 73.7% of patients. Anatomical location of meningioma, elevated ICP, the volume of meningioma and extent of peritumoral edema significantly influence the incidence of cognitive deficits. Post-operatively, the cognitive deficits improve significantly in the frontal and temporal group.

Use of thrombolytic therapy in cerebral venous sinus thrombosis with ulcerative colitis.

Cerebral venous thrombosis developing concurrently with active ulcerative colitis poses a therapeutic dilemma. We report the case of a 31-year-old woman who developed dural venous sinus thrombosis during the course of active ulcerative colitis in whom we accomplished clot lysis using intrasinus urokinase. The success of the procedure was assessed by improvement in the patient's neurological condition and resolution of imaging features without any bleeding complications. We also reviewed literature on various modalities of treatment of sinus venous thrombosis in patients with ulcerative colitis and outcome.

Validation of transcranial Doppler with magnetic resonance angiography in acute cerebral ischemia.

BACKGROUND AND PURPOSE: Transcranial Doppler (TCD) is often used as a screening tool for detecting intracranial stenosis. Since TCD results may vary among laboratories and sonographers, it requires validation against an imaging modality. We evaluated diagnostic accuracy of TCD performed in our laboratory against time-of-flight (TOF) magnetic resonance angiography (MRA) in detecting intracranial stenosis in patients with acute cerebral ischemia. METHODS: Consecutive patients with acute (<24 hours) cerebral ischemia and intracranial arterial stenosis on MRA underwent both TCD and MRA within 5 hours of each other. TCD was performed by credentialed neurosonologists according to standardized protocol. An independent neuroradiologist interpreting MRA was blinded to TCD findings. We evaluated TCD peak systolic velocities (PSV) in proximal intracranial arteries as predictive of moderate (>50%) and severe (>70%) stenosis on TOF-MRA. RESULTS: One hundred and fifty patients (74% males; mean age 53 years) underwent neurovascular evaluation with TCD and MRA. Twenty-two (14.6%) patients were excluded due to absent temporal acoustic windows. Middle cerebral artery TCD PSV values of >140 cm/s and >180 cm/s were found to predict a >50% and >70% focal stenosis, respectively. Optimal cut-off PSV values for other major proximal intracranial arteries were also established. CONCLUSIONS: TCD performed in our laboratory shows satisfactory agreement with TOF-MRA in diagnosis and grading of proximal intracranial stenosis in patients with acute cerebral ischemia.

Vascular cognitive impairment.

The term vascular cognitive impairment (VCI) has been proposed to encompass all people with cognitive impairment of cerebrovascular origin. VCI is not a single condition, but has several clinical presentations, etiologies, and treatment. VCI forms a spectrum that includes vascular dementia, mixed Alzheimer's disease with a vascular component, and VCI that does not meet dementia criteria. Multiple pathophysiological mechanisms contribute to VCI, accounting for its heterogeneity. Although main changes in the brain in VCI include cerebral infarcts, vascular cognitive impairment is thought to be due to factors beyond acute infarcts. Cerebral white matter lesions and silent brain infarcts are considered to be risk factors for VCI. The prevalence of VCI is high and this entity is poised to become the silent epidemic of the 21st century. Cognitive impairment due to cerebrovascular disease can to some extent be improved, and VCI prevented, if vascular risk factors are brought under control and strokes do not recur. Therefore, strategies that focus on the prevention and treatment of the cognitive impairment associated with cerebrovascular disease are high priority healthcare objectives.