Assessment of the Membranous Labyrinth in Infants Using a Heavily T2-weighted 3D FLAIR Sequence without Contrast Agent Administration.

BACKGROUND AND PURPOSE: Imaging is fundamental to assessing the acoustic pathway in infants with congenital deafness. We describe our depiction of the membranous labyrinth in infants using the heavily T2-weighted 3D FLAIR sequence without a contrast agent. MATERIALS AND METHODS: We retrospectively reviewed 10 infants (20 ears) (median term equivalent age: 2 weeks; IQR: 1-5 weeks) who had undergone brain MR imaging including a noncontrast heavily T2-weighted 3D FLAIR scan of the temporal bone. For each ear, 3 observers analyzed, in consensus, the saccule, the utricle, and the 3 ampullae, assessing the visibility (score 0, not appreciable; score 1, visible without well-defined boundaries; score 2, visible with well-defined boundaries) and morphology ("expected" or "unexpected" compared with adults). The heavily T2-weighted 3D FLAIR sequence was scored for overall quality (score 0, inadequate; score 1, adequate but with the presence of image degradation; score 2, adequate). RESULTS: Six (60%) MR examinations were considered adequate (score 1 or 2). The saccule was visible in 10 ears (83.3%) with an expected morphology in 9 ears (90%). In 1 ear of an infant with congenital deafness, the saccule showed an unexpected morphology. The utricle was visible as expected in 12 ears (100%). The lateral ampulla was visible in 5 ears (41.6%), the superior ampulla was visible in 6 ears (50.0%), and the posterior ampulla was visible in 6 ears (50.0%), always with expected morphology (100%). CONCLUSIONS: MR imaging can depict the membranous labyrinth in infants using heavily T2-weighted 3D FLAIR without an injected contrast agent, but the sequence acquisition time reduces its feasibility in infants undergoing MR studies during natural sleep.

COVID-19-Associated PRES-like Encephalopathy with Perivascular Gadolinium Enhancement.

We describe the case of a 63-year-old woman who developed a coronavirus disease 2019-associated acute encephalopathy with perivascular gadolinium enhancement.

Structural brain anomalies in Cri-du-Chat syndrome: MRI findings in 14 patients and possible genotype-phenotype correlations.

INTRODUCTION: Cri-du-Chat Syndrome (CdCS) is a genetic condition due to deletions showing different breakpoints encompassing a critical region on the short arm of chromosome 5, located between p15.2 and p15.3, first defined by Niebuhr in 1978. The classic phenotype includes a characteristic cry, peculiar facies, microcephaly, growth retardation, hypotonia, speech and psychomotor delay and intellectual disability. A wide spectrum of clinical manifestations can be attributed to differences in size and localization of the 5p deletion. Several critical regions related to some of the main features (such as cry, peculiar facies, developmental delay) have been identified. The aim of this study is to further define the genotype-phenotype correlations in CdCS with particular regards to the specific neuroradiological findings. PATIENTS AND METHODS: Fourteen patients with 5p deletions have been included in the present study. Neuroimaging studies were conducted using brain Magnetic Resonance Imaging (MRI). Genetic testing was performed by means of comparative genomic hybridization (CGH) array at 130 kb resolution. RESULTS: MRI analyses showed that isolated pontine hypoplasia is the most common finding, followed by vermian hypoplasia, ventricular anomalies, abnormal basal angle, widening of cavum sellae, increased signal of white matter, corpus callosum anomalies, and anomalies of cortical development. Chromosomal microarray analysis identified deletions ranging in size from 11,6 to 33,8 Mb on the short arm of chromosome 5. Then, we took into consideration the overlapping and non-overlapping deleted regions. The goal was to establish a correlation between the deleted segments and the neuroradiological features of our patients. CONCLUSIONS: Performing MRI on all the patients in our cohort, allowed us to expand the neuroradiological phenotype in CdCS. Moreover, possible critical regions associated to characteristic MRI findings have been identified.

Structural and metabolic differentiation between bipolar disorder with psychosis and substance-induced psychosis: An integrated MRI/PET study.

BACKGROUND: Bipolar disorder (BD) may be characterized by the presence of psychotic symptoms and comorbid substance abuse. In this context, structural and metabolic dysfunctions have been reported in both BD with psychosis and addiction, separately. In this study, we aimed at identifying neural substrates differentiating psychotic BD, with or without substance abuse, versus substance-induced psychosis (SIP) by coupling, for the first time, magnetic resonance imaging (MRI) and positron emission tomography (PET). METHODS: Twenty-seven BD type I psychotic patients with (n=10) or without (n=17) substance abuse, 16 SIP patients and 54 healthy controls were enrolled in this study. 3T MRI and 18-FDG-PET scanning were acquired. RESULTS: Gray matter (GM) volume and cerebral metabolism reductions in temporal cortices were observed in all patients compared to healthy controls. Moreover, a distinct pattern of fronto-limbic alterations were found in patients with substance abuse. Specifically, BD patients with substance abuse showed volume reductions in ventrolateral prefrontal cortex, anterior cingulate, insula and thalamus, whereas SIP patients in dorsolateral prefrontal cortex and posterior cingulate. Common alterations in cerebellum, parahippocampus and posterior cingulate were found in both BD with substance abuse and SIP. Finally, a unique pattern of GM volumes reduction, with concomitant increased of striatal metabolism, were observed in SIP patients. CONCLUSIONS: These findings contribute to shed light on the identification of common and distinct neural markers associated with bipolar psychosis and substance abuse. Future longitudinal studies should explore the effect of single substances of abuse in patients at the first-episode of BD and substance-induced psychosis.

Transthyretin Asn90 variant: amyloidogenic or non-amyloidogenic role.

A number of mutations were described in the TTR gene. They were generally related to a variety of inherited syndromes named 'familial TTR-related amyloidoses'. Although TTR mutations were mostly associated with familial amyloid polyneuropathy (FAP), these molecular variants were also found in patients with recurrent stroke, subarachnoidal bleeding and radiological findings of cerebral, cerebellar, cortical-subcortical infarctions and hemosiderosis. We describe a 46 y.o. man with recurrent cerebral haemorrhages carrying Asn90His variant of TTR gene. This mutation has been reported both in FAP and asymptomatic subjects raising the doubt on the possible amyloidogenetic role of this variant. The absence of mutation in the patient's father, who had a history of unexplained cerebral haemorrhage and the lack of symptoms and sign of cerebral bleeding in the two patient's sisters, carrying the same mutation, seem to support the hypothesis that His90Asn TTR mutation do not have an impact in amyloid formation. It has still to be established whether other gene variants in our patient could act synergistically with His90Asn TTR mutation in increasing the risk of CNS haemorrhages.

Safety of carotid stenting for stroke prevention: need of an independent outcome assessor.

Safety and efficacy of carotid artery stenting have still to be fully established. We propose a standardized registry of carotid artery stenting in use at our hospital to evaluate whether the presence of an independent neurologist performing basal, procedural and post-procedural observation increases the accuracy of outcome assessment. We collected a cohort of patients receiving carotid stenting. An external neurologist supervised the endovascular intervention and monitored the patient's clinical conditions during procedure and follow-up time (12 months). The procedure was carried out successfully in all cases. We registered two intra-procedural strokes and two strokes within 24 h. The risk of major complications in our study was 9.1% at 30 days. Our complication rate is higher than in previous studies. These findings could be partly explained by the unemployment of distal protection devices, but also by the presence of an independent observer that might have increased the accuracy of neurological evaluation.

Patterns of brain injury and outcome in term neonates presenting with postnatal collapse.

OBJECTIVE: To document perinatal events, brain imaging, neurophysiology and clinical outcome in term infants with early postnatal collapse (PNC). DESIGN: Tertiary referral centre, retrospective case review (1993-2006). PATIENTS: Infants born at > or =36 weeks' gestation with early (<72 h) PNC. Peri-partum and post-collapse data were collated with clinical, electrophysiological, neuroimaging and autopsy data and neurodevelopmental outcome. RESULTS: Twelve infants were studied; median gestation 39 weeks (36-41), birth weight 3150 g (1930-4010). Ten were born vaginally (including occipitoposterior (1), breech (2), water birth (2), ventouse/forceps (3)), and two by emergency caesarean section. Median Apgar scores were 9 (3-9) and 10 (8-10) at 1 and 5 min; median cord pH was 7.29 (7.18-7.34). All were thought to be well after birth. The median age at PNC was 75 min (10 min to 55 h). All infants required extensive resuscitation. The median pH after PNC was 6.75 (6.39-7.05). Seven infants became severely encephalopathic, with severely abnormal EEG/aEEG recorded within 12 h. MRI showed acute severe hypoxic-ischaemic injury. All died. One infant showed rapid recovery, had mild encephalopathy, and good outcome. Four infants had severe respiratory illness, normal background EEG, and MRI showing slight white matter change (n = 3) or a small infarction (n = 1). All had a good 2-year outcome. CONCLUSIONS: In this term cohort, early PNC was generally followed by severe encephalopathy, acute central grey matter injury and poor outcome, or severe respiratory illness, slight white matter change and good outcome. Early EEG and MRI predicted outcome accurately. However, no antepartum, intrapartum or other aetiological factors were identified. Further investigation is needed in larger PNC cohorts.

Distinctive abnormalities of motor axonal strength-duration properties in multifocal motor neuropathy and in motor neurone disease.

The strength-duration function is a classic measure of neural excitability. When studied on peripheral motor axons it reflects the intrinsic nodal membrane properties, and its time-constant (tau(SD) or chronaxie) predominantly depends on non-voltage-gated, rest Na(+) inward conductances. We assessed the strength-duration curve of ulnar motor axons in 22 nerves of healthy controls, in 18 nerves of patients with multifocal motor neuropathy with conduction blocks (MMN), and in 19 nerves of patients with motor neurone disease (MND). The compound muscle action potential (CMAP) was smaller in nerves of both groups of patients than in controls (P < 0.05). The rheobasic current (rh(50%)) [mean +/- standard deviation (SD)] was higher in patients with MMN than in controls (13.3 +/- 16.3 mA; controls 4.7 +/- 1.7 mA, P < 0.05). The tau(SD) was differentially abnormal in the nerves of the two groups of patients: it was prolonged in the nerves of patients with MND for >or=40 years (227.2 +/- 34.5 micro s; controls 190.9 +/- 51.0 micro s, P < 0.05), but it was shortened in the nerves of patients with MMN (146.5 +/- 55.4 micro s; controls 208.6 +/- 51.2 micro s, P < 0.05) who had not been treated recently with high-dose intravenous immunoglobulin (IVIg). Nerves of patients with recently treated MMN (<6 weeks) who were under the therapeutic effect of IVIg had a normal tau(SD)(.) Our results suggest that, probably due to an immuno-mediated rest Na(+) channel dysfunction, Na(+) conductances are reduced in MMN. This abnormality is a function of the time after the last IVIg treatment and involves also the axonal membrane outside the conduction block. Conversely, in MND, possibly owing to the ionic leakage of degenerating membrane, rest Na(+) conductances are increased. Measuring the strength-duration curve of the ulnar motor axons might be useful in the differential diagnosis between de novo MMN and MND.

Anatomo-clinical correlation of intraoperative stimulation-induced side-effects during HF-DBS of the subthalamic nucleus.

The efficacy of deep brain stimulation of the subthalamic nucleus (STN) is dependent on the accuracy of targeting. In order to reduce the number of passes and, consequently, the duration of surgery and risk of bleeding, we have set up a new method based on direct magnetic resonance imaging (MRI) localisation of the STN. This procedure allows a short duration of the neurophysiological session (one or two initial tracks). Whenever a supplementary track is needed, the stimulation-induced side effects are analysed to choose from one of the remaining holes in Ben's gun. A good knowledge of anatomical structures surrounding the STN is mandatory to relate side effects to the actual position of the track. In our series of 11 patients (22 sides, 37 tracks), the most common and reproducible side effects were those characterised by motor, sensorial, oculomotor and vegetative signs and symptoms. Moreover, the therapeutic window (distance between the current intensity needed to obtain the best clinical effect and the intensity capable to induce side effects) predicted clinical efficacy in the long-term, and contributed to the choice of which among the examined tracks had to be implanted with the chronic macroelectrode.

Decreased EMG inhibition following electrical stimulation over muscle tendons in myopathies.

OBJECTIVE: To assess the central EMG inhibitory action of tendon afferent input in muscle diseases. METHODS: The EMG inhibition elicited by electrical stimulation over muscle tendons was tested in 13 healthy voluntary subjects and 8 patients who had a primary muscle disease with a mild force deficit. Electrical stimuli were delivered to the tendon of the extensor carpi radialis muscle at the wrist during tonic voluntary isometric contraction at 50% of the maximum EMG level. The EMG signal was recorded by surface electrodes over the extensor carpi radialis muscle. RESULTS: The prestimulus background EMG level was reduced in 7 out 8 of the patients. Both groups had the same phases of EMG modulation following tendon stimulation (TE1, TI1, TE2) and their latency and amplitude did not differ significantly. Conversely, the area of TI1 was significantly larger (i.e. the inhibition decreased) in patients ([mean+/-SD] absolute area: controls=4.1+/-1.6 mVms, patients=6.9+/-2.9 mVms, P<0.05). CONCLUSIONS: In muscle dysfunction there are serial 'upstream' changes of central inhibitory systems, probably to maximize the residual muscle power of the affected muscle.

Non-motor effects of deep brain stimulation of the subthalamic nucleus in Parkinson's disease: preliminary physiological results.

Although deep brain stimulation (DBS) is a clinically effective therapy for patients with advanced Parkinson's disease (PD), its physiological effects on the brain and possible actions on non-motor functional systems remain largely unknown. This study evaluated the effects of DBS of the subthalamic nucleus (STN) on neurophysiological variables and on cardiovascular physiology. Nine patients affected by PD undergoing chronic DBS of the STN have been studied. We performed electroencephalography (EEG), somatosensory (SEPs) and visual evoked potentials (VEPs), exteroceptive masseteric silent period and sympathetic skin response (SSR) studies with DBS ON and OFF. To assess the effects of stimulation on the cardiovascular system the tilt test and plasma renin activity were studied. When we turned the DBS OFF, both SEP N20 and the VEP P100 component increased significantly in amplitude whereas the SSR decreased in amplitude and increased in latency. Although plasma renin activity tended to increase with DBS OFF, its modification induced by postural changes and blood pressure values did not significantly differ with DBS ON and OFF. We conclude that DBS of the STN in PD, besides inducing a clinical improvement, induces several non-motor effects.