Ritva Paetau - Academia.edu (original) (raw)

Papers by Ritva Paetau

PubMed, Apr 1, 1991

The Landau-Kleffner syndrome (LKS) is characterized by electroencephalographic spike discharges a... more The Landau-Kleffner syndrome (LKS) is characterized by electroencephalographic spike discharges and verbal auditory agnosia in previously healthy children. We recorded magnetoencephalographic (MEG) spikes in a patient with LKS, and compared their sources with anatomical information from magnetic resonance imaging. All spikes originated close to the left auditory cortex. The evoked responses were contaminated by spikes in the left auditory area and suppressed in the right--the latter responses recovered when the spikes disappeared. We suggest that unilateral discharges at or near the auditory cortex disrupt auditory discrimination in the affected hemisphere, and lead to suppression of auditory information from the opposite hemisphere, thereby accounting for the two main criteria of LKS.

The Journal of Pediatrics, 1988

Pediatric Research, Oct 1, 1986

Pediatric Research, Dec 1, 1991

Developmental Medicine & Child Neurology, Oct 18, 2001

Pediatric Neurology, Sep 1, 2005

Research findings concerning cognitive effects of pediatric epilepsy surgery form an important ba... more Research findings concerning cognitive effects of pediatric epilepsy surgery form an important basis for decisions about surgery. However, most follow-up studies have been of limited duration. In this study, a 2-year follow-up of intelligence was undertaken. Risk factors were analyzed. Included were 38 patients aged 3 to 17 years. Surgery was left in 19 patients and right in 19 patients. Types of surgery included temporal lobe resection (n = 23), extratemporal or multilobar resection (n = 8), and hemispherectomy (n = 7). The Wechsler Scales of Intelligence were administered presurgically, 6 months postsurgically, and 2 years postsurgically. No significant change in verbal or performance intelligence quotient (IQ) was demonstrated on a group level. Lateralization, type of surgery, age at surgery, sex, and presurgical IQ did not affect outcome. Across assessments, IQ scores of left-hemisphere patients were lower than those of right-hemisphere patients. Scores of patients in the hemispherectomy group were lower than those of the extratemporal or multilobar resection group, which were lower than the temporal lobe resection group. Scores improved significantly in six patients and deteriorated in seven. In conclusion, epilepsy surgery in children and adolescents does not, in general, have a significant impact on cognitive development in a 2-year perspective. In individual patients, poor seizure control and extensive surgery for Rasmussen&amp;amp;amp;#39;s encephalitis were related to a deterioration of IQ.

Scandinavian Journal of Infectious Diseases, 1989

Severe encephalitis associated with disseminated echovirus 22 infection occurred in a previously ... more Severe encephalitis associated with disseminated echovirus 22 infection occurred in a previously healthy 5-month-old boy. Echovirus 22 was diagnosed by a seroconversion both in serum and cerebrospinal fluid and by isolation of the virus from several stool samples. The child damaged severely and at the age of 8 1/2 months infantile spasms developed.

Purpose. Focal cortical dysplasias (FCDs) are the most common single pathology found in epilepsy ... more Purpose. Focal cortical dysplasias (FCDs) are the most common single pathology found in epilepsy surgery patients (Frater et al., 2000, Sisodiya, 2004). The outcome of surgery is generally favorable and seizure-free outcomes of 50-75% have been reported (Fauser et al., 2008, 2002, Sisodiya, 2004). Incomplete resection of an FCD is the main predictor of poor post-surgical outcome (Krsek et al., 2009). Magnetoencephalography (MEG) and EEG reflect postsynaptic currents in pyramidal cells. MEG is selectively sensitive to tangential currents, typically produced by fissure walls. Because the bottom of sulci are predilection sites for FCD lesions, we investigated whether MEG results could predict clinical outcome in epilepsy surgery patients with FCD. We specially focused on patients with no visible lesions on magnetic resonance imaging (MRI). Methods. MEG findings of 30 epilepsy surgery patients with confirmed histological diagnosis of FCD subtypes I or II (Palmini et al. 2004) were retrospectively evaluated. MEG was recorded as a part of their pre-surgical planning. Tens of single (non-averaged) MEG spikes were modeled with equivalent current dipoles, and the dipole sets were classified into 'scattered' or 'clustered' according to Iida et al (2005). We studied the MEG dipole localizations in respect to the removed area defined by postoperative MRI scans, and evaluated the value of MEG-findings in predicting the seizure outcome after surgery (according to Engel 1993). In patients with no visible 3-Tesla MRI lesion (n=12), the location of MEG dipoles were also compared with localization results of subdural and/or depth electrode EEG. Results. Inter-ictal MEG spikes were observed in all but one patient. Dipole clusters were found in sixteen (53%) patients. Twelve of the 30 (40%) patients became seizure free (Engel class I). Four of the seventeen (24%) patients with FCD I and eight of the thirteen (62%) patients with FCD II became seizure free (p=0.05). In patients with dipole clusters and favorable outcome Engel class I or II (n=11), 51% of the source clusters had been removed; while in patients with unfavorable outcome (Engel class III or IV; n=5) only 5.5% of the cluster volume had been removed (p=0.02).

BMJ, Jul 4, 1987

Cyst infection in acquired renal cystic disease Cystic degeneration of the kidney in patients wit... more Cyst infection in acquired renal cystic disease Cystic degeneration of the kidney in patients with advanced renal failure is common'; whether cysts can harbour infection remains to be shown.2 We report on three cases of infected cysts in acquired renal cystic disease. Case reports Case I-A 60 year old man was admitted to hospital because of uraemia, hypertension, recurrent fever, and leucocytosis. The plasma concentration of creatinine was 821 !umol/l, and a urine culture was positive for Escherichia coli. Ultrasonography showed normal sized hyperechogenic kidneys with more than three 1-2 cm cysts in each. There was a 6 cm cyst that was hyperechogenic at the upper pole of the left kidney. Renal computed tomography confirmed the presence of bilateral multiple cysts. A thick wall, enhanced by contrast infusion, was seen around a slightly dense cyst on the upper pole of the left kidney (figure). 3 Embrey MP, Graham NB, McNeill ME. Induction oflabour with a sustained-release prostaglandin E2 vaginal pessary. BrMed3' 1980;251:901-2. 4 Ulmsten U, Wingerup L, Ekman G. Local application of prostaglandin E2 for cervical ripening or induction of term labor. ClGn Obstet Gynecol 1983;26:95-105. 5 Seppila E, Pora 0, Metsai-Keteli T. A modified method for extraction and purification of prostaglandins with resin XAD-2. Prostaglandins, Leukoriens Med 1984;14:235-41.

Movement Disorders, May 1, 2000

Lazarus' Sign in Brain Death Brain death (BD) is the irreversible loss of function of the brain, ... more Lazarus' Sign in Brain Death Brain death (BD) is the irreversible loss of function of the brain, including the brain stem. 1,2 Criteria for the diagnosis of BD require complete unresponsiveness, apnea, and absent brain stem reflexes. 1,3,4 A videotape accompanies this article.

International Journal of Computer Assisted Radiology and Surgery, 2011

Methods A novel nTMS system (eXimia NBS, Nexstim Oy) was used in 120 patients for motor (n = 110)... more Methods A novel nTMS system (eXimia NBS, Nexstim Oy) was used in 120 patients for motor (n = 110) as well as speech cortex mapping (n = 10). The nTMS results were integrated with the anatomical data using multimodal software (iPlan Cranial software, Brainlab AG) via DICOM export. The cortical hot spots of motor and speech representation were used to initiate DTI tracking (n = 70). The resulting image was then used for surgical planning (Fig. 1). The data were introduced into the surgical environment via microscope display. iES was performed in 73 cases. Results Integration of the functional and anatomical data was successful in all 120 patients. The nTMS data permitted standardized DTI fibre visualization in all 70 cases. The resulting cartography led to modification of the initial treatment plan in 53% of cases. iES guided by the preoperative data confirmed the nTMS assessment in respect to identification of the primary motor cortex as well as white matter tract displacement in all...

Epilepsy Research, 2018

Drug resistant epilepsy (DRE) is common in patients with tuberous sclerosis (TS). Interictal MEG ... more Drug resistant epilepsy (DRE) is common in patients with tuberous sclerosis (TS). Interictal MEG has been shown as a valuable instrument in the presurgical workup. The goal of our study was to evaluate the role of ictal MEG in epileptogenic tuber selection, especially in patients with multiple irritative zones. Methods: The clinical and MEG data of 23 patients with TS and DRE from two medical/research centers were reviewed. Seven pediatric patients, who had seizures during MEG recording and underwent resection or disconnection surgery, were included into the study. Cortical sources of ictal and interictal epileptiform MEG discharges were compared with epileptogenic zone location in six patients with favorable surgery outcome. Results: In patients who improved substantially after surgery all resected and several other tubers demonstrated epileptiform activity on interictal MEG. Ictal MEG provided crucial information about lobar location of the seizure onset zone (SOZ) in two cases, and in the other four it confirmed the SOZ location derived from the interictal data. In one case, ictal MEG findings were unreliable. In one patient, who did not benefit from surgical treatment, the resected tubers did not overlap with interictal and ictal MEG sources. Conclusion: The combination of interictal and ictal MEG is a valuable tool for identification of the epileptogenic tuber/tubers in presurgical work-up in patients with TS. This study was approved by the ethical committees of Moscow State

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Neuron, Jan 5, 2018

Channelopathies are disorders caused by abnormal ion channel function in differentiated excitable... more Channelopathies are disorders caused by abnormal ion channel function in differentiated excitable tissues. We discovered a unique neurodevelopmental channelopathy resulting from pathogenic variants in SCN3A, a gene encoding the voltage-gated sodium channel Na1.3. Pathogenic Na1.3 channels showed altered biophysical properties including increased persistent current. Remarkably, affected individuals showed disrupted folding (polymicrogyria) of the perisylvian cortex of the brain but did not typically exhibit epilepsy; they presented with prominent speech and oral motor dysfunction, implicating SCN3A in prenatal development of human cortical language areas. The development of this disorder parallels SCN3A expression, which we observed to be highest early in fetal cortical development in progenitor cells of the outer subventricular zone and cortical plate neurons and decreased postnatally, when SCN1A (Na1.1) expression increased. Disrupted cerebral cortical folding and neuronal migratio...