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Biomedical subjects

Adriana Bastos Conforto

Publications and source records attributed to Adriana Bastos Conforto.

11 recordsLinked to original sources
PubMed2007

Bilateral occipital infarcts associated with carotid atherosclerosis and a persistent hypoglossal artery.

The persistent hypoglossal artery (PHA) is the second most common persistent embryological carotid-basilar connection and usually represents an incidental finding in cerebral arteriograms. The hypoglossal artery connects the primordial carotid artery with the longitudinal neural arteries, which later form the basilar artery. The PHA leaves the internal carotid artery as an extracranial branch, enters the skull through the anterior condyloid foramen, the hypoglossal canal and joins the caudal portion of the basilar artery. We report magnetic resonance and digital subtraction angiography findings in the first case of bilateral occipital infarctions associated with PHA and carotid atherosclerosis. The probable mechanism underlying bilateral occipital infarcts was embolism from the carotid territory to the posterior cerebral arteries. PHA may present a challenge in diagnosis and management of patients with carotid atherosclerosis and vertebrobasilar ischemia.

Aged↗
PubMed2006

An integrative transcranial magnetic stimulation mapping technique using non-linear curve fitting.

The aim of this study is to develop a new simple method for analyzing one-dimensional transcranial magnetic stimulation (TMS) mapping studies in humans. Motor evoked potentials (MEP) were recorded from the abductor pollicis brevis (APB) muscle during stimulation at nine different positions on the scalp along a line passing through the APB hot spot and the vertex. Non-linear curve fitting according to the Levenberg-Marquardt algorithm was performed on the averaged amplitude values obtained at all points to find the best-fitting symmetrical and asymmetrical peak functions. Several peak functions could be fitted to the experimental data. Across all subjects, a symmetric, bell-shaped curve, the complementary error function (erfc) gave the best results. This function is characterized by three parameters giving its amplitude, position, and width. None of the mathematical functions tested with less or more than three parameters fitted better. The amplitude and position parameters of the erfc were highly correlated with the amplitude at the hot spot and with the location of the center of gravity of the TMS curve. In conclusion, non-linear curve fitting is an accurate method for the mathematical characterization of one-dimensional TMS curves. This is the first method that provides information on amplitude, position and width simultaneously.

Adult↗
PubMed2006

Estimating the number of motor units using random sums with independently thinned terms.

The problem of estimating the numbers of motor units N in a muscle is embedded in a general stochastic model using the notion of thinning from point process theory. In the paper a new moment type estimator for the numbers of motor units in a muscle is denned, which is derived using random sums with independently thinned terms. Asymptotic normality of the estimator is shown and its practical value is demonstrated with bootstrap and approximative confidence intervals for a data set from a 31-year-old healthy right-handed, female volunteer. Moreover simulation results are presented and Monte-Carlo based quantiles, means, and variances are calculated for N in{300,600,1000}.

Adult↗
PubMed2006

Comparison between digital subtraction angiography and magnetic resonance angiography in investigation of nonlacunar ischemic stroke in young patients: preliminary results.

PURPOSE: We preliminarily investigated the relevance of performing digital subtraction angiography (DSA) in addition to magnetic resonance angiography (MRA) in definition of ischemic stroke etiology in young patients. METHOD: DSAs and MRAs from 17 young patients with nonlacunar ischemic stroke were blindly analyzed and their impact on stroke management was evaluated. RESULTS: Etiologies were the same considering results of either DSA or MRA in 12/17 cases. In 15/17 patients no changes would have been made in treatment, regardless of the modality of angiography considered. CONCLUSION: These preliminary results suggest that DSA may be redundant in two thirds of ischemic strokes in young patients. Further larger prospective studies are necessary to determine indications of DSA in this age group.

Adolescent↗
PubMed2006

Cerebral microbleeds and intravenous thrombolysis: case report.

Intravenous thrombolysis is an important procedure that has significant impact on ischemic stroke prognosis. However, intracranial hemorrhage (ICH) is a feared complication of this procedure. It has been suggested that cerebral microbleeds (CMBs) may increase the risk of ICH after thrombolysis. We report on a 69 years-old woman with multiple CMBs submitted to intravenous thrombolysis without complications.

Aged↗
PubMed2005

Facial sensory symptoms in medullary infarcts.

OBJECTIVE: To investigate the correlation between facial sensory abnormalities and lesional topography in eight patients with lateral medullary infarcts (LMIs). METHOD: We reviewed eight sequential cases of LMIs admitted to the Neurology Division of Hospital das Clínicas/São Paulo University between July, 2001 and August, 2002 except for one patient who had admitted in 1996 and was still followed in 2002. All patients were submitted to conventional brain MRI including axial T1-, T2-weighted and Fluid attenuated inversion-recovery (FLAIR) sequences. MRIs were evaluated blindly to clinical features to determine extension of the infarct to presumed topographies of the ventral trigeminothalamic (VTT), lateral spinothalamic, spinal trigeminal tracts and spinal trigeminal nucleus. RESULTS: Sensory symptoms or signs were ipsilateral to the bulbar infarct in 3 patients, contralateral in 4 and bilateral in 1. In all of our cases with exclusive contralateral facial sensory symptoms, infarcts had medial extensions that included the VTT topography. In cases with exclusive ipsilateral facial sensory abnormalities, infarcts affected lateral and posterior bulbar portions, with slight or no medial extension. The only patient who presented bilateral facial symptoms had an infarct that covered both medial and lateral, in addition to the posterior region of the medulla. CONCLUSION: Our results show a correlation between medial extension of LMIs and presence of contralateral facial sensory symptoms.

Adult↗
PubMed2005

Bilateral olivary hypertrophy after unilateral cerebellar infarction.

We describe a case of bilateral olivary hypertrophy and palatal tremor after unilateral cerebellar infarction. Hypertrophic olivary degeneration (HOD) is associated with hypersignal in the inferior olivary nucleus (ION), on T2-weighted images. HOD has been more often observed ipsilaterally to a central tegmentum tract lesion or contralaterally to a dentate nucleus or a superior cerebellar peduncle lesion. Double innervation of each ION from either dentate nucleus may have underlied the imaging and clinical findings in this 63 year-old male patient.

Cerebral Infarction↗
PubMed2004

Progressive cervicocranial arteriopathy with dilatations and stenoses: case report.

We report the case of a 36 year-old woman who presented occlusion of a basilar artery fusiform aneurysm (FA) associated with pontine infarction, and two episodes of subarachnoid hemorrhage possibly due to arterial dissection. She also had asymptomatic FAs in the right middle cerebral and left internal carotid arteries. Over 5 years, lesions suggestive of fibromuscular dysplasia in the right vertebral artery and occlusion of the left vertebral artery were observed. This combination of lesions emphasizes the possibility of a common pathogenetic mechanism causing different degrees of media disruption in cervicocranial arteries.

Adult↗
PubMed2004

Impact of coil position and electrophysiological monitoring on determination of motor thresholds to transcranial magnetic stimulation.

OBJECTIVE: We compared motor and movement thresholds to transcranial magnetic stimulation (TMS) in healthy subjects and investigated the effect of different coil positions on thresholds and MEP (motor-evoked potential) amplitudes. METHODS: The abductor pollicis brevis (APB) 'hot spot' and a standard scalp position were stimulated. APB resting motor threshold (APB MEP-MT) defined by the '5/10' electrophysiological method was compared with movement threshold (MOV-MT), defined by visualization of movements. Additionally, APB MEP-MTs were evaluated with the '3/6 method,' and MEPs were recorded at a stimulation intensity of 120% APB MEP-MT at each position. RESULTS: APB MEP-MTs were significantly lower by stimulation of the 'hot spot' than of the standard position, and significantly lower than MOV-MTs (n=15). There were no significant differences between the '3/6' and the '5/10' methods, or between APB MEP amplitudes by stimulating each position at 120% APB MEP-MT. CONCLUSIONS: Coil position and electrophysiological monitoring influenced motor threshold determinations. Performing 6 instead of 10 trials did not produce different threshold measurements. Adjustment of intensity according to APB MEP-MT at the stimulated position did not influence APB MEP amplitudes. SIGNIFICANCE: Standardization of stimulation positions, nomenclature and criteria for threshold measurements should be considered in design and comparison of TMS protocols.

Adult↗
PubMed2003

Treatment of subclavian steal syndrome with percutaneous transluminal angioplasty and stenting: case report.

Subclavian steal syndrome refers to the association of neurological symptoms related to vertebrobasilar insufficiency and the phenomenon of subclavian steal. We report the case of a 63 year-old male patient that presented subclavian steal syndrome and severe proximal (80%) stenosis of the left subclavian artery. The patient was submitted to percutaneous transluminal angioplasty and stenting on the left SA. The procedure was well tolerated and immediately afterwards, there was complete remission of the symptoms and of the phenomenon of subclavian steal evaluated by angiography and transcranial doppler. We propose that percutaneous transluminal angioplasty with stenting placement is a good therapeutic option for subclavian steal syndrome.

Angioplasty, Balloon↗