Biomedical subjects

Soheyl Noachtar

Publications and source records attributed to Soheyl Noachtar.

6 recordsLinked to original sources

PubMed2003

Increased muscle activity during rapid eye movement sleep correlates with decrease of striatal presynaptic dopamine transporters. IPT and IBZM SPECT imaging in subclinical and clinically manifest idiopathic REM sleep behavior disorder, Parkinson's disease, and controls.

STUDY OBJECTIVES: Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by complex behavior during REM sleep. The etiology of this disorder is still unknown, but a recent study showed that RBD precedes symptoms of Parkinson disease (PD) by several years, and in a previous study, we found reduced striatal dopamine transporters in idiopathic clinically manifest RBD. DESIGN: Hypothesizing that subclinical RBD shows a less severe reduction of striatal dopamine transporters than clinically manifest RBD, we studied striatal postsynaptic dopamine D2-receptors with (S)-2hydroxy-3iodo-6-methoxy-([1-ethyl-2-pyrrolidinyl]methyl) benzamide labeled with iodine 123 (IBZM) and the striatal presynaptic dopamine transporters with (N)-(3-iodopropene-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane labeled with iodine 123 (IPT) using single-photon emission computed tomography (SPECT) in the following groups: 8 patients with idiopathic subclinical RBD, 8 patients with idiopathic clinically manifest RBD, 11 controls, and 8 patients with PD stage Hoehn & Yahr I. RESULTS: The IPT uptake was highest in controls. There was a significant decrease in IPT uptake from controls to patients with subclinical RBD, from patients with subclinical RBD to clinically manifest RBD, and from patients with clinically manifest RBD to patients with PD (controls: right = 4.07 +/- 0.29, left = 4.07 +/- 0.30; subclinical RBD: right = 3.56 +/- 0.21, left = 3.55 +/- 0.25; clinically manifest RBD: right = 3.18 +/- 0.43, left = 3.2 +/- 0.43; PD: ipsilateral to the clinically affected body side = 3.25 +/- 0.35, contralateral to the clinically affected body side = 2.51 +/- 0.28). Muscle activity during REM sleep lasting persistently longer than 0.5 seconds was independently associated with reduction of striatal dopamine transporters (P = 0.001). The IBZM uptake was not significantly different between the groups. CONCLUSIONS: This study suggests that there is a continuum of reduced striatal dopamine transporters involved in the pathophysiologic mechanisms causing increased muscle activity during REM sleep in patients with subclinical RBD.

Adult↗

PubMed2002

The localizing value of the abdominal aura and its evolution: a study in focal epilepsies.

OBJECTIVE: To evaluate the localizing value of abdominal aura and its evolution into other seizure types. METHODS: The seizures of 491 consecutive patients with focal epilepsies were prospectively classified according to a recently introduced semiologic seizure classification. All patients underwent prolonged EEG video monitoring and MRI scan. Two hundred twenty-three patients (45%) had temporal lobe epilepsies (TLE); 113 patients (23%) had extratemporal epilepsies; and for 155 (32%) patients, the epilepsy could not be localized to one lobe. RESULTS: Abdominal auras were more frequent with TLE (117 of 223 patients, 52%) than in extratemporal epilepsy (13 of 113 patients, 12%, p < 0.0001) and more frequent in mesial TLE (70 of 110 patients, 64%) than in neocortical TLE (16 of 41 patients, 39%, p = 0.007). No preponderance to one side existed. Abdominal auras were followed by ictal oral and manual automatisms (automotor seizure) in at least one seizure evolution in all patients with TLE (117 patients, 100%). In contrast, only two patients with extratemporal epilepsy (2 of 13 patients, 15%, p < 0.0001) had abdominal auras evolving into automotor seizures. An abdominal aura is associated with TLE with a probability of 73.6%. The evolution of an abdominal aura into an automotor seizure, however, increases the probability of TLE to 98.3%. CONCLUSIONS: These results demonstrate that evolution of abdominal aura into automotor seizure permits differentiation between temporal lobe epilepsy and extratemporal epilepsy, showing that analysis of seizure evolution provides more localizing information than does the frequency of particular seizure types.

Abdomen↗

PubMed2002

Naming tools and animals: asymmetries observed during direct electrical cortical stimulation.

Semantically bounded disorders of verbal processing that result in selective dysnomias for items belonging to specific semantic categories have been well documented in lesion studies. Most commonly dissociations between the categories of living versus non-living things have been reported. Processing of living things such as animals seems to be impaired after bilateral lesions, whereas lesions resulting in impairment of processing of non-living things such as tools seem to be restricted to the left hemisphere. In this study, we tested the naming capabilities of epilepsy patients with subdural electrodes implanted for localization of the epileptogenic zone and preoperative mapping of cognitive functions. Tool and animal items were used, and the results show that during stimulation of the left hemisphere dysnomias for tool items were more pronounced than for animal items. This asymmetry is discussed within a model of more widely bilaterally distributed processing of living category members as compared to more restricted left-sided representation of non-living category members.

Adolescent↗

PubMed2002

Focal epileptiform activity in the brain: detection with spike-related functional MR imaging--preliminary results.

The purpose of this study was to develop a spike-related functional magnetic resonance (MR) imaging method to detect epileptic brain activity. Correlations between simultaneous spike-related functional MR imaging and electroencephalographic (EEG) recordings were performed in 10 patients with focal epilepsy. Postprocessing techniques were implemented to eliminate contamination of the EEG recording from ballistocardiography and the echo-planar MR imaging sequence. A diagnostic EEG recording was achieved during functional MR imaging. Spike location correlated with the site of blood oxygen level-dependent signal increase. Spike-related functional MR imaging is a promising technique for detecting focal epileptic brain activity.

Adult↗

PubMed2002

Clinical features and EEG findings differentiating mesial from neocortical temporal lobe epilepsy.

We evaluated whether mesial temporal lobe epilepsy (MTE) and neocortical temporal lobe epilepsy (NTE) can be distinguished on electroclinical grounds. One hundred and twenty-two consecutive MTE (n = 86) and NTE (n = 36) patients were included in this prospective study. All patients underwent prolonged EEG-video monitoring and high resolution magnetic-resonance imaging (MRI). MTE was defined as epilepsy with purely mesial temporal lesion in the absence of extramesial temporal pathology, based on pre-operative MRI or post-operative histology. NTE was defined as neocortical temporal MRI lesions, depth recorded neocortical temporal seizure onset and lack of mesial temporal lesions on MRI or histology. One thousand two hundred and fourty-nine epileptic seizures were analyzed. Congenital malformation (NTE 19% versus MTE 3%, P < 0.01), nonspecific auras (NTE 25% versus MTE 8%, P < 0.001) and early clonic activity following automatisms (NTE 22% versus MTE 8%, P < 0.03) were more frequent in NTE. In contrast, a history of febrile seizures (MTE 29% versus NTE 3%, P < 0,001), abdominal auras (MTE 62% versus NTE 33%, P < 0.005) and contralateral hand dystonia (MTE 43% versus NTE 22%, P < 0.03) were more often documented in MTE. Interictal epileptiform discharges in MTE occurred predominantly (> 67%) over the ipsilateral mesial temporal regions (MTE 65% versus NTE 33%, P < 0.001). No MTE patient had lateral neocortical temporal spike predominance (NTE 22%, P < 0.001). Multiple logistic regression revealed that a history of febrile seizures, abdominal auras, contralateral dystonic posturing and predominance of ipsilateral mesial temporal spikes point to MTE, with an accuracy of 73% (PPV 81%, NPV 70%). Analyzing clinical and EEG features, particularly the distribution of interictal epileptiform discharges, helps to differentiate between MTE and NTE.

Adult↗

PubMedDate not supplied

Headache associated with epileptic seizures: epidemiology and clinical characteristics.

OBJECTIVE: To investigate the incidence and characteristics of seizure-associated headaches and the modalities of treatment. BACKGROUND: Systematic investigations of the characteristics of seizure-associated headaches are rare. Although data in the literature on the incidence of postictal headaches range between 37% and 51%, experiences with their treatment are limited and pathophysiological concepts do not exist. METHODS: One hundred ten epileptic outpatients from an epilepsy referral center participated in a semi-standardized interview about headaches associated with epileptic seizures. The characteristics of these patients and of 15 additionally recruited patients with known postictal headaches were analyzed. RESULTS: The incidence of seizure-associated headaches was 43% (n = 47). Forty-three patients had exclusively postictal headaches. One patient had exclusively preictal headaches. Three patients had both pre- and postictal headaches. The duration of postictal headaches was longer than 4 hours in 62.5% of the patients. In the majority of patients, postictal headaches occurred in more than 50% of the seizures. Postictal headaches were treated by self-medication in 19 patients (30%). No patient treated headaches according to a medical prescription. In 11 patients, postictal migraine was untreated. Postictal headaches were associated with focal seizures in 23 patients and/or with generalized seizures in 54 patients. According to the headache classification of the International Headache Society, headaches were classified as migraine-type in 34% of patients and as tension-type headache in 34% of patients. Headaches could not be classified in 21% of patients. Patients with and without postictal headaches did not differ as to localization of the epileptogenic zone or to the number of prescribed antiepileptic drugs. There was no relationship between the localization of the epileptogenic focus, localization of the headache, or the headache classification. CONCLUSIONS: Headaches associated with partial and generalized seizures are frequent and undertreated. Treatment should consider both the headache syndrome and the general guidelines for treating primary headaches. The pathophysiology of seizure-associated headaches cannot be explained by the epileptic syndrome.

Adult↗