2-15-03 Conventional and topographic mapping EEG: diagnostic value in patients with closed head injury

Electroencephalography

& Related Techniques

12-l 4-07 1 Cerebrospinal fluid measures of disease activity in patients with multiple sclerosis F. Sellebjerg ’ Department Copenhagen, Diagnostics,

2-15-02

1,2 , M Christiansen 2, P.M. Nielsen ‘, J.L. Frederiksen ‘. of Neurology, University of Cqoenhagen, Glostrup Hospital, Denmark, 2Depatiment of Clinical Biochemistryl Sector of Statens SeruminstiU, Copenhagen, Denmark

R. Granillo, Neurologfa

P. Stourac, P. Vondracek. Department Bohunice, Brno, Czech Republic

of Neurology.

evaluation

Universify

of

2-15-03

Hospital

Electroencephalography Techniques

& Related

Mathematical analysis

method for GPi firing discharge

J. Balej, M. Delfino, H. Garcia, A. Cammarota, D. Cerquetti, M. Merello, Ft. Leiguarda. Movement Disorders Section, Raul Cama lnstirute for Neurological Research (FLENI), Buenos Aires, Argentina Single unit Basal Ganglia recording has yielded useful insights into Parkinson’s disease pathophysiology. It has been postulated that GPi firing patterns rather than filing rates could determine specific motor manifestations. On-line firing rate and firing pause analysis seems insufficient to provide discharge pattern information over a long fixed period of time, so that off-line signal recording analysis is required. Single GPi unit discharge and raster display are digitised by means of an analogue digital converter (CED 1401) and recorded in appropriate software (SIGAVG). Gabor’s transform was applied on raw data and raster display. Single units were analysed separately during periods exceeding 180 sec. Sustained 200 f 50 Hz discharge was accompanied by harmonics of higher frequency and a sequential repetitive pattern. Discharge patterns were clearly different by Gabor’s transform within neighbouring units with motor drive and between the latter and those without motor drive. In conclusion, off-line mathematical analysis by means of Gabor’s transfon may provide additional information for single unit discharge discrimination.

de

Conventional and topographic mapping EEG: diagnostic value in patients with closed head injury A. Jovicic, Belgmde,

E. Dincic. Department Yugoslavia

of Neurology

In order to determine diagnostic value, in terms of severity, duration and spatial distribution of neurophysiologic changes, we compared conventional and topographic mapping EEG findings. Twenty eight patients, who showed cerebral concussion syndrome after closed head injury, were investigated with conventional and topographic mapping EEG recording. All of subjects complained on prolonged headaches and memory disturbances. Registration of EEG data was undertaken in period between a few hours to one-year after head trauma. Updated diagnostic and therapeutic guidelines were applied for treatment of those patients. We observed clearly relationship on trauma severity and EEG changes, comparing EEG findings to neurologic examination and medical history. Moreover, topographic mapping EEG provided better neurophysiological changes display. With simultaneously using conventional and topographic mapping EEG techniques, we found numerous advantages of quantitative method, particularly following: (1) higher sensitivity in detection of changes, which are otherwise undetectable; (2) better spatial resolution. According to our experience, we propose topographic mapping EEG as a mandatory investigation in the standard diagnostic protocole for evaluation head injury severity.

I

2-l 5 04

R. Naumovski, Macedonia

2-l 5-01 IXI

N. EstBvez. Laboraforio de Neurofisiologia Clinica, Servicio Clinica. Hospital Militar Central, Buenos Aires, Argentina

M. Mihajlovic, M. Zecevic, Military Medical Academy;

The distinction between atypical reactive processes and lymphoma in the cerebrospinal fluid /CSF/ may be very difficult in some cases. The main objective of this pilot study was to evaluate the significance of the morphological features of the suspicious CSF cells for the definite diagnosis of lymphoma. The diagnostic lumbar puncture was performed in the group of fifteen patients /n = 15/with positive neurological symptoms. The cerebrospinal fluid specimen was cytocentrifuged and stained with May-Griinwald-Giemsa stain. We considered, as cytologic criteria for lymphoma, large size of cells, paler and coarser chromatin, bizarre nuclear shapes and often multiple nucleoli. Our results show, that in thirteen cases /88%/ the cell population was relatively homogenous and in the consent with the above stated criteria. In two cases /140/d we found cells strongly resembling lymphoma, but the cell population was hetercgenous. The final diagnosis was the reactive and inflammatory reaction in these two cases. Here we conclude, that the only morphological criteria of CSF cells need not be enough for definite diagnosis of malignant lymphoma in CSF. Some additional diagnostic tools, mainly immunocytochemistry could solve such diagnostic problems.

15

Brain mapping: Spectral analysis in a sample of non-pathologic EEGs

We studied the distribution of frequencies in 70 adult people (aged 15-6Q years) without detectable neurological or psychiatric diseases. EEGs were recorded in awake, resting subjects with closed eyes, using the lo/20 electrode system. In each EEG, 40 samples (1 set) were selected for spectral analysis. Surfaces under the frequency curve were calculated for each band. In this normal population, values did not exceed 200 (delta), 100 (theta), 400 (alpha). Since changes in delta and theta bands are good indicators of abnonality, we studied the ratios between slow (delta + theta) and fast (alpha + beta 1) activities. The slow area was less than 7,000 whereas the fast area greatly exceeded those values (more than 100%). There was a large correlation (r = -0.9) between the slow and fast activities. A similar coefficient was found for the ratio delta-alpha. By contrast, there was no correlation between delta-theta. There were significant regional differences. Frontal: delta, 54.5; theta, 38.8; alpha, 75. Temporocentral: delta, 42.5; theta, 34.4; alpha 84.1. Posterior: delta, 27.3; theta, 27.9; alpha 117.7. These values supportthe presence of delta and alpha gradientes, with a uniform theta. These values are currently used as standards in our laboratory.

The use of magnetic resonance imaging as a surrogate marker of disease activity in patients with multiple sclerosis (MS) is increasingly reccgnised. In contrast, the use of cerebrospinal fluid analysis has recently received less attention. We analysed the correlation between clinical data and cerebrospinal fluid parameters in 75 patients with acute optic neuritis (ON) as a possible first symptom of MS, as a symptom of clinically definite MS, and in patients with an attack of MS other than ON. The concentration of myelin basic protein (MBP) in cerebrospinal fluid was significantly correlated to the visual acuity in patients with ON and to the Kurtzke EDSS score in patients with MS. The concentration of MBP in CSF also correlated positively to the CSF leukocyte count, intrathecal IgG synthesis, and the CSF-serum albumin concentration quotient. The concentration of MBP in CSF correlated negatively to intrathecal IgA synthesis. The results support the use of the concentration of MBP in CSF as a surrogate marker of disease activity during acute exacerbations of MS; the data also link the presence of MBP in CSF to neuroimmunological parameters.

2 14 08 Diagnostic problems in the cytologic LI.-c-l cerebrospinal fluid for lymphoma

s93

Percent variations of the spectral power in epileptic patients after long-term monotherapy with epial (Carbamazepine) M. Pashu.

Clinic of Neurology,

Faculty

of Medicine,

Skopje,

Carbamazepine (CBZ) was initiated in 28 patients for seizure control, in whom, in hospital conditions epilepsy was diagnosed for the first time, previously they did not administer any antiepileptic drugs or some other drugs which would influence the EEG, and they all had normal CT and neurologic finding. Each patient underwent a series of EEG in the following order: before the CBZ initiation seven days after the start of the therapy and the control recordings after one and six months; in every repeated recording EEG the serum drug level of Carbamezepine was controlled ranging in therapeutic rank. For percent analysis of the band power at least 100 seconds of the recordings were selected, divided in epochs with timeduration longer than 4 seconds; the analysis was made for 16 leads on the scalp, but due to the spatial limitation, results for Fp2, C4, T4 and 02 leads were shown. The basis of normative values of 50 control persons served for values comparison obtained from the groups of patients. The following results were received: (1) in alpha and beta frequency areas and the band power percent values did not show any significant differences between the control group and the findings of the patients in different time intervals; (2) the percent of delta power did not show significant difference in any lead between the normative values and the patients’ finding received before the CBZ initiation. After 7-day treatment with CBZ there was a significant increase of the band power percent; increased values persisted in the following three record recording as well, but their fluctuation had no statistical