A multiparametric MRI study of frontal lobe dementia in multiple sclerosis

Previous studies achieved conflicting results when correlating magnetic resonance imaging (MRI) abnormalities and cognitive impairment in multiple sclerosis (MS) patients. Recently, the estimation of MS lesion load on T1-weighted images and the analysis of magnetization transfer ratio (MTR) histograms, increased the degree of the correlation between physical disability and MRI findings in MS. We assessed the relationship of conventional and non-conventional MRI-derived measures with frontal lobe dementia in MS. Dual echo, T1-weighted and MT MRI scans of the brain were obtained in 11 MS patients with and in 11 without frontal lobe dementia, matched for age, sex, education and disability. Total (TLL) and frontal (FLL) lesion loads were assessed from T2- and T1-weighted scans. MTR histogram analysis was performed for the whole brain, the frontal lobe and the cerebellum. Median TLL and FLL were significantly higher in cognitively impaired patients on both T2- and T1-weighted scans. The MRI measure that better discriminated the two groups of patients was T1-weighted TLL (median values were 19.1 ml for demented and 1.9 ml for non-demented patients, P=0.006). Average MTR, peak height and location of overall brain and frontal lobe histograms were significantly lower for cognitively impaired than for cognitively intact patients (P values ranged from 0.0001 to 0.001). Cerebellar MTR histogram metrics did not significantly differ in patients with and without cognitive decline. The presence of cognitive decline in MS is associated with the extent and pathological severity of brain MRI abnormalities.     

Electroencephalographic coherence analysis in multiple sclerosis: correlation with clinical, neuropsychological, and MRI findings

OBJECTIVE: To explore functional corticocortical connections in multiple sclerosis by means of coherence of the EEG, and to evaluate their correlations with the degree of cognitive impairment and with brain lesion load assessed by MRI. METHODS: EEG coherence was studied from 28 patients with clinically definite multiple sclerosis. Ten minutes of resting EEG were recorded with 20 scalp electrodes, with binaural reference. FFT power and coherence were calculated in artifact free epochs of 1 second and compared with values from 22 control subjects of comparable age and sex distribution. Patients also underwent MRI (n=27) and neuropsychological examination (n=21). RESULTS: Compared with controls, patients with multiple sclerosis showed increased theta power in the frontotemporal-central regions (p<0.005). theta Band coherence was decreased between homologous areas (p<0.02). alpha Band coherence was decreased both in the local and long distance connections (p<0.0005). These findings were most striking both in patients with high MRI subcortical lesion load and in patients with cognitive involvement. A significant correlation was found between interhemispheric theta (p=0.02) and alpha (p=0. 017) and anteroposterior alpha (p=0.013) coherence and subcortical MRI lesion load, but not with exclusively periventricular lesion load. CONCLUSIONS: These findings support the hypothesis that cognitive impairment in multiple sclerosis is mostly dependent on involvement of corticocortical connections related to demyelination and/or axonal loss within the white matter immediately underlying the cortex.     

From primary progressive aphasia to corticobasal syndrome: two clinical and rCBF functional reports

We describe two cases, both presenting with a 2-year history of isolated language disorders, one compatible with logopenic variant and the other with non-fluent variant of primary progressive aphasia (PPA). Afterwards, each developed a corticobasal syndrome (CBS) with alien limb phenomenon and a multi-domain cognitive impairment. Regional cerebral perfusion (rCBF) study using 99mTc-ECD single photon emission computed tomography (SPECT) revealed hypoperfusion patterns consistent with these aphasia types and with the presence of limb apraxia. We report two cases of PPA variants associated with CBS and we suggest that SPECT rCBF correlates can be useful in making a differential diagnosis within the PPA spectrum.     

Cognitive assessment in multiple sclerosis—an Italian consensus

The aim of this consensus paper was to define the state of the art on cognitive assessment of persons with multiple sclerosis (PwMS), with the purpose of providing recommendations for the Italian centers involved in MS management. While there are no formal guidelines published regarding the assessment of cognitive function in MS, on the basis of an expert opinion meeting, held in Milan (Italy) on July 4, 2016, we report the recommendations of a panel of Italian experts including MS neurologists and neuropsychologists for the assessment and follow-up of cognitive function in adult MS subjects.     

Delayed hyperbaric oxygen treatment after acute carbon monoxide poisoning

Journal of Neurology -     

Treatment of Wernicke’s encephalopathy with high dose of thiamine in a patient with pyloric sub-stenosis: description of a case

Wernicke’s encephalopathy (WE) is an acute or subacute syndrome that results from a deficiency in vitamin B1 (thiamine). The syndrome is characterised by a classical triad of symptoms: nystagmus and ophthalmoplegia, mental-status changes, and unsteadiness of stance and gait. When patients with WE are inappropriately treated with low doses of thiamine, mortality rates average out at 20% and Korsakoff’s Psychosis develops in about 85% of survivors (Sechi and Serra in Lancet Neurol 6(5):442–455, 2007). We report the case of a patient with a pyloric sub-stenosis that developed a WE, and was treated with high doses of thiamine showing after few days of treatment a great improvement of neurological and neuroradiological assessment, even though cognitive impairment was still severe at discharge and at 6 months follow-up.     

EEG correlates of cognitive impairment in MS

Cognitive impairment is a frequent complication of multiple sclerosis (MS), generally reflecting subcortical dementia. In order to explore functional cortico-cortical connections in MS, we studied electroencephalogram (EEG) coherence in a group of 21 clinically defined MS patients. Patients also underwent magnetic resonance imaging (MRI) and neuropsychological examinations. Compared to unimpaired MS patients, cognitively involved patients had reduced short-distance and long-distance theta and alpha band coherencies. Anteroposterior and interhemispheric coherencies were significantly correlated with MRI lesion load immediately underlying cortex but not were exclusively associated with periventricular lesions. These data support the hypothesis that cognitive impairment in MS is mostly related to demyelination or axonal loss of cortico-cortical connections. In a second study, we evaluated the neurophysiological correlates of frontal lobe dysfunction. Frontal lobes are also involved in motor planning and execution. We evaluated the EEG movement-related potential (MRP) in MS patients with and without frontal neuropsychological deficits. Reaction times to the Stroop test, which evaluates frontal functions, and MRP components were delayed in both MS groups compared to normal subjects and in frontal compared to nonfrontal MS patients. These data suggest that frontal cognitive involvement in MS corresponds to abnormal bioelectrical activity also during simple motor tasks.