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Biomedical subjects

A Bernasconi

Publications and source records attributed to A Bernasconi.

At least 55 records · Page 3Linked to original sources
PubMed1998

Morphometric analysis of the temporal lobe in temporal lobe epilepsy.

PURPOSE: Using high-resolution magnetic resonance imaging (MRI), we examined the temporal neocortex and the underlying white matter in patients with unilateral temporal lobe epilepsy (TLE) and in control subjects. METHODS: The images of 27 patients and 42 control subjects were registered into stereotaxic space, corrected for image intensity inhomogeneity, and automatically segmented into gray matter, white matter, and cerebrospinal fluid (CSF) over a predetermined extent of the temporal lobe. The surface between the gray matter and CSF was extracted, indices of curvature (IOC) of the surface were calculated, and a frequency histogram of the IOC was obtained. RESULTS: There was significant bilateral reduction in the total volume of the temporal lobe and in the volume of gray matter. White matter volume was significantly reduced only in the temporal lobe ipsilateral to the seizure focus. There were significant changes in the position and amplitude of peaks in the frequency histogram of the IOC. CONCLUSIONS: The volume of gray matter was negatively correlated with duration of epilepsy, suggesting that neocortical changes may be a consequence of seizures. Changes in the frequency histogram of the IOC suggested an additional alteration in the surface morphology of the temporal lobe in TLE, possibly related to sulcal widening.

Adolescent↗
PubMed1998

Celiac disease, bilateral occipital calcifications and intractable epilepsy: mechanisms of seizure origin.

PURPOSE: To elucidate the mechanisms of seizure origin in patients with celiac disease and bilateral occipital calcifications (CEBOC). Individuals with CEBOC frequently present with occipital lobe seizures, but additional lesions and additional attack patterns may occur. METHODS: We studied two men and one woman who had CEBOC. Villous atrophy was revealed in the two patients who underwent duodenal biopsy. All had a comprehensive presurgical evaluation, including prolonged video-EEG recordings. Two had magnetic resonance imaging (MRI) with volumetric study of mesial temporal structures (MRIV). One patient had undergone stereotactic intracranial depth electrode studies (SEEG). RESULTS: All patients presented with intractable complex partial seizures. Two had partial simple seizures with visual aura. Neurologic examination was normal; one was of normal intelligence, and two were mildly retarded. Neuroimaging studies showed that each had bilateral occipital calcifications as well as epileptiform abnormalities over temporal lobes. In one, MRI showed an additional right frontal lesion, but SEEG demonstrated right occipital lobe seizure origin with anterior spread; this male patient later underwent a right occipital lobe resection. Another with a history of prolonged febrile convulsions had bilateral hippocampal and amygdalar atrophy demonstrated by MRIV. CONCLUSIONS: In one patient, SEEG confirmed that seizures originated in the occipital lobe. The presence of dual pathology was demonstrated in another, raising the possibility of both occipital and temporal seizure onset. The presence of extraoccipital lesions or of mesial temporal atrophy requires SEEG for clarification of seizure onset. In the absence of confounding factors and when laterality can be demonstrated, surgical treatment may be considered.

Adult↗
PubMed1998

Nocturnal temporal lobe epilepsy.

OBJECTIVE: To analyze clinical, electrophysiologic, and neuroradiologic characteristics and prognostic factors in a group of patients with temporal lobe epilepsy (TLE) and complex partial seizures (CPS) occurring exclusively or predominantly after they fall asleep or before they awaken. BACKGROUND: CPS arising during sleep are classically identified with frontal lobe epilepsy. TLE associated with seizures occurring only or predominantly during sleep (nocturnal TLE) is less common. METHODS: From a series of patients with refractory TLE studied between 1980 and 1996, the authors identified 26 patients (15 men) with nonlesional nocturnal TLE (mean age, 40 years). Clinical and laboratory characteristics of these individuals were studied and compared with a group of 72 age-matched, randomly selected patients with nonlesional TLE and predominantly diurnal seizures (diurnal TLE). RESULTS: Mean age at seizure onset was similar for both groups (16.3 versus 18.7 years). In the nocturnal TLE group, 2 of 26 patients had a positive family history of epilepsy, 18 reported an aura, 4 presented with CPS in clusters, 11 had unilateral and 15 bilateral temporal EEG abnormalities, and 14 of 21 studied had unilateral mesial temporal atrophy. None of these factors differed significantly in the two groups except for higher frequency of the following in the diurnal TLE group compared with the nocturnal TLE group: positive family history for epilepsy (33% versus 8%, p=0.01), estimated frequency of seizures (median, 14 versus 2 per month; p < 0.01), and presence of antecedent febrile convulsions (33% versus 11%, p=0.04). In the nocturnal TLE group, eight patients underwent surgical therapy and became seizure free (follow-up, > 12 months). Only two were seizure free on medication. CONCLUSIONS: Infrequent and nonclustered seizures, rare family history of epilepsy, and low prevalence of childhood febrile convulsions characterize nocturnal TLE. Within the TLEs, the nocturnal TLE form seems to have a better surgical prognosis.

Adult↗
PubMed1997

Medial medullary stroke: report of seven patients and review of the literature.

Medial medullary infarctions (MMI) were reported in less than 40 patients with satisfactory clinicotopographic documentation. We studied seven patients with MRI-proven acute MMI seen in two neurologic departments over a 5-year period (1990-1994). MMI represented less than 1% of ischemic strokes in the posterior circulation. Five patients had an infarction above the pyramidal decussation. All patients had contralateral hemiparesis and lemniscal sensory loss, accompanied by ipsilateral lingual palsy (Dejerine's syndrome) in three. Two patients had infarction below the pyramidal decussation, with ipsilateral hemiparesis and lemniscal sensory loss. Accompanying symptoms and signs of MMI were vertigo and nausea (n = 5), mild ipsi- or contralateral decrease in pain sensation (n = 6), headache (n = 4), ipsilateral limb ataxia (n = 6), contralateral truncal lateropulsion (n = 5), mild ipsilateral ptosis (n = 4), nystagmus (n = 4), dysarthria (n = 3), and somnolence (n = 2). Presumed causes of MMI were stenosis, occlusion or dissection of the ipsilateral vertebral artery (n = 5), and cardioembolism (n = 1). Outcome at 3 months was favorable in five patients. In conclusion, the clinical features of MMI are more heterogeneous than commonly thought, whereas its etiology seems fairly constant (vertebral artery disease).

Adult↗
PubMed1996

Acute multiple infarction involving the anterior circulation.

OBJECTIVE: To evaluate the frequency and clinical, topographic, and etiologic patterns of acute multiple infarction involving the anterior circulation. DESIGN: Data analysis from a prospective acute stroke registry in a community-based primary care center. RESULTS: Among 751 patients with first ischemic stroke in the anterior circulation over a 4-year period, 40 patients (5%) had acute multiple infarcts involving the anterior circulation. On computed tomography and magnetic resonance imaging with gadolinium enhancement, there were four topographic patterns of infarction: (1) superficial infarcts (11 patients [28%]); (2) superficial and deep infarcts (12 patients [30%]); (3) deep infarcts (three patients [8%]); and (4) infarcts involving the anterior and the posterior circulation (14 patients [35%]). Both cerebral hemispheres were involved in one fourth of the cases. A specific clinical picture was found in up to 20% of the patients. This included global aphasia with left hemianopia, hemisensory loss or hemiparesis (in right-handed patients), transcortical mixed aphasia with hemianopia, and acute pure cognitive impairment ("dementia"). Large-artery disease was found in 13 patients (33%); a cardiac source of embolism was found in 11 patients (28%); and both were found in three patients (8%). Bilateral infarcts were related to cardioembolism (four patients) and bilateral large-artery disease (three patients). One month after stroke, one fourth of the patients were independent, one third had some disability, and 40% were either dead or completely dependent. CONCLUSIONS: Acute multiple infarcts involving the anterior circulation may be bilateral more frequently than is currently thought, and they are often associated with posterior circulation infarcts. They mainly involve the pial hemispheral territories, commonly being caused by cardioembolism or bilateral carotid atheroma. They may be associated with a specific neurologic-neuropsychological dysfunction pattern in up to one fifth of the patients, allowing diagnosis before brain imaging.

Adult↗
PubMed1996

Is local myocardial contractility related to endocardial acceleration signals detected by a transvenous pacing lead?

The availability of sensors monitoring cardiac function parameters may offer many interesting new applications in cardiac pacing. A microaccelerometer sensor (BEST, Biomechanical Endocardial Sorin Transducer) located at the tip of a pacing lead (PL) has been developed by Sorin Biomedica. The signal detected by the accelerometer, peak endocardial acceleration (PEA), was shown to reflect cardiac contractility and to be related to the dP/dt signal. Whether the PEA detected by the BEST sensor in different cardiac locations is the expression of local acceleration forces or reflects the whole heart contractility has not yet been demonstrated in humans. Endocardial acceleration and PEA were evaluated in five patients (4 males, 1 female, mean age 68 years) who underwent cardiac catheterization. Sinus rhythm was present in four patients and chronic atrial fibrillation was present in one. The BEST PL was introduced through the left subclavian vein and PEA signals were recorded: (1) at the apex of the right ventricle (RV), (2) within the coronary sinus (CS), (3) at the right atrial appendage (RAA), and (4) floating in the right atrium. The PEA signals were recorded simultaneously with surface ECG, intracardiac electrograms, and RV pressure. At each recording site, PEA signals with significant amplitude were always recorded during the preejection period, during the isovolumic contraction phase, independently of the recording site and cardiac rhythm. The PEA amplitude was higher in the RV (mean value 1.32 g) and it decreased in the RAA and CS (0.75 and 0.45 g, respectively). The same behavior of PEA was observed during sinus rhythm or atrial fibrillation. The amplitude and the timing of the PEA signals detected by the BEST accelerometer were independent of the recording site and atrial rhythm; they appeared to be strictly related to the global ventricular contractility. These results suggest that the BEST could be used either as an effective sensor in closed loop pacing systems, or primarily as a diagnostic hemodynamic sensor.

Acceleration↗
PubMed1996

Multiple acute infarcts in the posterior circulation.

OBJECTIVE: to evaluate clinical, radiological, and prognostic features of patients with multiple acute infarcts in remote arterial territories of the posterior circulation. DESIGN: Data analysis from a prospective acute stroke registry in a community based primary care centre using a standard protocol including MRI and MRA. RESULTS: In three and a half years, 27 of the 236 patients (11%) with posterior circulation stroke had multiple acute infarcts in the posterior circulation as shown by gadolinium enhancement on MRI. Eighteen patients had multiple infratentorial and supratentorial infarcts including the cerebellum and posterior cerebral artery territory, with coexisting brainstem involvement in seven patients. Fourteen patients had a rostral basilar artery syndrome and cerebellar signs; four patients had a visual field defect with cerebellar signs. Causes were vertebral (six) or basilar (four) artery atheromatosis, and cardioembolism (four). Seven patients had multiple acute infarcts in the posterior circulation of the cerebellum and lower brainstem. Brainstem and cerebellar signs were found in most patients (five); aetiologies were small vessel disease (four), cardioembolism (one), and vertebral artery dissection (one). Two patients with large artery atheromatosis had multiple acute infarcts in the posterior circulation in the brainstem and posterior cerebral artery territory. One month after stroke more than 25% of the patients were dependent or had died. There was no difference in the outcome between the three groups, and recovery was linked to the size of infarcts rather than to a high number of infarcts. CONCLUSIONS: multiple acute infarcts in the posterior circulation usually involve the cerebellum. Simultaneous brainstem and posterior cerebral artery territory infarcts sparing the cerebellum are uncommon. They can be suspected clinically before neuroimaging, mainly when supratentorial and infratentorial infarcts coexist. This may be important, because different patterns of infarction are associated with different causes of stroke.

Activities of Daily Living↗
PubMed1996

[Peripheral nerve and spinal cord complication in intravenous heroin addiction].

The neurological complications observed in 6 HIV negative intravenous drug users are reported. Four developed acute neuromuscular involvement in a lumbosacral or brachial distribution with rhabdomyolysis, myoglobinuria, hypovolemia, renal and hepatic failure in the 3 most severely affected patients. Despite evidence of immunologic abnormalities and especially presence of anti-heroin antibodies, we feel that causative mechanisms include mixed compression and ischemia with an underlying toxic myopathy, resulting in segmental myopathy with secondary compression of peripheral nerves. Two patients developed myelopathy with acute or chronic onset. The mechanisms were vascular with spinal cord infarction in the acute form and probably infectious with secondary compressive arachnoiditis in the chronic form. In these 2 patients with myelopathy, outcome was poor.

Acute Disease↗
PubMed1991

[Assessment of early complications of kidney transplantation. Is duplex-Doppler useful for the diagnosis of acute rejection?].

The authors studied with duplex-Doppler US 28 renal transplant recipients in 31 clinically different episodes, during the early postoperative period. Morphological data were thus obtained, as well as hemodynamic information. According to the literature on the subject, a pulsatility index (PI) greater than 1.5 was considered as abnormal. US diagnosis was retrospectively compared with final clinical diagnosis and with response to therapy. In one case, the kidney was surgically removed. We evaluated US sensitivity and specificity in the diagnosis of acute rejection with real-time US, Doppler alone and combined with duplex. A PI greater than or equal to 1.5 corresponded to acute rejection, with 60% sensitivity and 85.7% specificity. With a PI greater than 1.8, sensitivity decreased to 50%, but specificity increased to 100%. The severest changes in Doppler waveforms had a bad prognostic significance. Besides poor specificity--which is so often emphasized in literature--our results chiefly demonstrated sensitivity limitations, partly corrigiable with real-time US signs, together with Doppler PI (sensitivity: 90%, specificity: 85.7%). Duplex-Doppler US, in spite of its well-known limitations, remains therefore a simple, rather reliable and non-invasive technique to study renal transplant complications.

Acute Disease↗
PubMed1989

[Pulmonary eosinophilic granuloma in adults. Case histories and a review of the literature].

Histiocytosis X is a disease of unknown origin which usually affects multiple organs, including the lung. The age of onset, the clinical course and the pattern of spread allow a distinction to be made between 3 varieties: Letterer-Siwe, Hand-Schüller-Christian and eosinophilic granuloma. The latter form, in adult patients, may predominantly or solely affect the lungs. The authors reviewed clinical, radiographic and CT findings of 7 adult patients with pulmonary eosinophilic granuloma, picked out of a series of 265 cases of interstitial lung pathology, diagnosed since 1973. Typical pulmonary involvement is bilateral, symmetrical and predominates in the upper areas. Honeycomb pattern was found in 1 patient at the onset of symptoms, and in 2 cases during the follow-up, without severe reduction in pulmonary volumes. Pneumothorax was observed in 3 cases and bone lesions in 2. CT added new and important informations such as presence, size and wall thickness of "cystic" lesions. New laboratory tests and bronchoalveolar lavage demonstrated minor diagnostic usefulness than radiological findings. The authors conclude by discussing such problems as prognostic factors and differential diagnosis.

Adolescent↗