Έδωσα εξετάσεις για toefl, gre general gre subject καθώς και εξετάσεις στο Ίδρυμα Κρατικών Υποτροφιών

Abstract

Aim of the study: Brainstem Auditory Evoked Responses (BAERS) and Vestibular Evoked Myogenic Potentials (VEMPS) are used for studying auditory and vestibular function, respectively. We have initiated a study of Multiple Sclerosis Patients, in order to investigate the diagnostic value of both recordings and in particular of the second VEMP wave n34-p44. We also comment on the hypothesis that the n34 and p44 VEMP components are of cochlear origin.

Materials and Methods: We have studied 31 MS patients with auditory and /or vestibular symptoms. 9 patients presented with unilateral deafness (group 1), 8 with bilateral tinnitus (group 2) and 14 with vertigo (group 3). VEMPS and BAERS have been recorded and assessed. We also investigate 30 healthy volunteers recording VEMP to determine normal individual limits.

Results:

In Group 1, the second wave n34p44 gave as one abnormal case, out of total 9 cases, that at the same time is characterized as normal by the first VEMP wave p12n23. In Group 3, the second wave n34p44 give also information for one abnormal case, out of total 14 cases, that at the same time is characterized as normal by the first VEMP wave p12n23. Thus the second wave provides added non trivial diagnostic value.

In group 1, VEMPS results regarding the fist wave p13n23 were normal. At the same time the n34-p44 was present in the unaffected ear only. Conclusively, n34p44 was absent in 7 patients, although the vestibular VEMPS component p13n23 was normal. In group 2, BAERS and all but one p13n23 were normal, yet n34p44 was bilaterally absent in 3 patients. In group 3, all but one BAERS were normal, while p13n23 wave was bilaterally absent in 6 patients and prolonged in 8 patients .The n34p44 complex was bilaterally absent in 3 patients.

We found no association (“correlation”) between patients with abnormal VEMPS and patients with abnormal BAEPS in our study. We also found that the unilateral presentation of n34p44 wave in group 1 was related with abnormal BAERS in the affected ear.

Conclusion: The second wave n34p44 provides added non trivial diagnostic value. It adds to the set of abnormal cases a clear (meaning cases otherwise normal for p13n23 wave) 11% in group1 and a 7% in group3.

Another important result of our study (coming from group1) is the following. n34p44 wave is not present in all normal subjects; whenever it exists it is bilateral. In our patients its unilateral presentation was related with abnormal BAERS in the affected ear. This supports the hypothesis that n34p44 are of cochlear origin.

Statistical methods

The intraclass correlation coefficients of type C following a two way random model for measuring reliability was calculated. Side differences for all the factors were compared with the Wilcoxon signed ranks test since most of variables are not normally distributed. Differences for all the factors between our four groups were compared with nonparametric tests for two independent samples. We calculated group differences using the Wilcoxon rank two-sample test and the Mann-Whitney U test. Further we checked for possible associations between the various abnormalities performing a correspondence analysis. We did not choose a chi-squared test since entries in our crosstabulation table include counts smaller than 5. In all cases a significant difference indicates P<0.05.

Novelty – Impact

Στην εργασία αυτή διαπιστώνουμε για πρώτη φορά μέσω της στατιστικής επεξεργασίας ότι το δεύτερο μέρος της μετρούμενης κυματομορφής VEMP έχει σημαντική διαγνωστική αξία. Το εύρημα αυτό είναι κεφαλαιώδδους σημασάις για την χρησιμότητα των VEMPS ως μέθοδος διάγνωσης. Το δεύτερο μέρος της κυματομορφής μέχρι τώρα δεν είχε μελετηθεί διεξοδικά και δεν χρησιμοποιούνταν για διάγνωση.

18. Ferekidou E, Eleftheriadou A, Zarikas V, Kandiloros D, Yiotakis I, Ferekidis E, Korres S.

“Acoustic Stapedial Reflex in normal adults: biological behaviour and determination of threshold levels by detecting the Admittance (Y) and his components Susceptance (B) and Conductance (G).”

ORL, Journal Otorhinolaryngol Relat Spec. 2008;70(3):176-84. Epub 2008 Apr 8.

Abstract

Objective

The aim of this study was to record the acoustic reflex threshold for the Admittance (Y), Susceptance (B) and Conductance (G) in a large sample of healthy subjects and to establish normative data.

Study design

Acoustic reflex threshold was determined in 100 healthy persons, divided in 5 age-related groups (20-29, 30-39, 40-49, 50-59 and 60-69) numbering 20 persons each. Detection was performed for (Y) and its components, (B) and (G) at 226, 678 and 1000 Hz probe tones, using reflex activator signals 500, 1000, 2000 and 4000 Hz.

Results. Statistically significant difference was revealed between separate measurements. The lowest threshold level was recorded for Y at 226 Hz using stimulus 1000 Hz. Subjects belonging to different age groups had different reflex thresholds.

Conclusion: Inclusion of measurements for B and G in acoustic reflex detection offer more detailed information about the middle ear status compared with Y alone, and appears to be sensitive in detecting subtle diseases.

Novelty – Impact

Στην εργασία αυτή μελετούμε για πρώτη φορά τις μεταβολές των acoustic thresholds για όλους του συνδυασμούς των συνιστωσών Y, B, G και για τρεις διαφορετικές συχνότητες probe tone και τέσσερεις διαφορετικές συχνότητες stimuli. H σημασία της μελέτης είναι μεγάλη διότι σε αρκετές περιπτώσεις ασθενών δεν καταγράφονται μετρήσεις για tone 226 Hz που χρησιμοποιείται ευρέως και έχει μελετηθεί.

19. V. Zarikas , A. Christopoulos, V.L. Rendoumis

«A thermodynamic approach for the description of the time evolution of a stock market index»

Proceedings of 6th International Conference in Applied Financial Economics, 2009 Samos July 02-04, 2009