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Biomedical subjects

K Priftis

Publications and source records attributed to K Priftis.

11 recordsLinked to original sources
PubMed2006

P300-based brain computer interface: reliability and performance in healthy and paralysed participants.

OBJECTIVE: This study aimed to describe the use of the P300 event-related potential as a control signal in a brain computer interface (BCI) for healthy and paralysed participants. METHODS: The experimental device used the P300 wave to control the movement of an object on a graphical interface. Visual stimuli, consisting of four arrows (up, right, down, left) were randomly presented in peripheral positions on the screen. Participants were instructed to recognize only the arrow indicating a specific direction for an object to move. P300 epochs, synchronized with the stimulus, were analyzed on-line via Independent Component Analysis (ICA) with subsequent feature extraction and classification by using a neural network. RESULTS: We tested the reliability and the performance of the system in real-time. The system needed a short training period to allow task completion and reached good performance. Nonetheless, severely impaired patients had lower performance than healthy participants. CONCLUSIONS: The proposed system is effective for use with healthy participants, whereas further research is needed before it can be used with locked-in syndrome patients. SIGNIFICANCE: The P300-based BCI described can reliably control, in 'real time', the motion of a cursor on a graphical interface, and no time-consuming training is needed in order to test possible applications for motor-impaired patients.

Adult↗
PubMed2005

Hospitalizations for childhood asthma in Athens, Greece, from 1978 to 2000.

Trends in rates of asthma admissions among children have shown a variety of patterns in different countries in the last decades. We undertook the present study to determine the time trends in asthma admissions and readmissions of children in Athens, Greece. Data were obtained retrospectively from hospital registries of the three main children's hospitals in Athens from 1978 to 2000. Children admitted with the diagnoses of asthma, asthmatic bronchitis or wheezy bronchitis were included. Hospital admission rate for asthma among children 0-14 yr from 1978 to 2000 rose by 271% (p <0.001). The rise in rates among those aged 0-4 and 5-15 yr were 250% and 276%, respectively. The mean annual increase in admission rate was 12.2% for 1978-1987, 4.7% for 1988-1993 and 0.6% for 1994-2000. The readmission rate among children 0-14 yr was increased from 15.3% to 23.3%. A positive correlation between admission and readmission rates in all age groups was observed. In conclusion, our findings show an increase in the childhood asthma admission rate in Athens in late 1970's and during the 1980's, which has decelerated in the 1990's, particularly in the second-half of the decade. The readmission rate paralleled that of admissions over the entire study period.

Adolescent↗
PubMed2003

Growth of asthmatic children before long-term treatment with inhaled corticosteroids.

The aim of this study was to examine the growth of asthmatic children before any long-term inhaled corticosteroid treatment. We studied 436 asthmatic children (254 boys and 182 girls), age range 3.9-15.4 years, that had not been treated with long-term inhaled corticosteroids. In each child height and weight were measured, and the height standard deviation score (HSDS) and the weight for height ratio (%WFH) were calculated. We also estimated asthma severity and tested atopic status by skin testing. Children were grouped into three age groups: prepuberty (3.9-7.9 years), peripuberty (8-11.9 years), and puberty (12-15.5 years). HSDS was correlated to asthma severity and duration, atopic status, and other coexisting allergic diseases. Seven hundred ten healthy children (345 boys, 365 girls) ages 4.1-15.5 years were used as controls for height and weight. There was no statistically significant difference in HSDS and %WFH between patients and controls, except for HSDS of pubertal female patients that was significantly less than that of controls, x: 0.06 (0.80) vs. x: 0.40 (0.90), respectively, p < 0.02. There was also no significant correlation between HSDS or %WFH and severity or duration of the disease, allergy status and other coexisting allergic diseases. However, there was significant difference in menarcheal age between asthmatic girls x: 12.49 (0.12) and controls x: 12.00 (0.10), p < 0.001. In conclusion, our data show that the growth of asthmatic children before any long-term treatment with inhaled corticosteroids is not different from the control population, except for the asthmatic girls of pubertal age who are shorter than control girls probably because of delay in pubertal maturation.

Administration, Inhalation↗
PubMed2001

Prevalence of asthma among schoolchildren in Patras, Greece: three surveys over 20 years.

BACKGROUND: The aim of the present study was to compare the prevalence of asthma among schoolchildren in 1978, 1991, and 1998 in Patras, Greece. METHODS: The study populations of the three comparable cross sectional surveys comprised third and fourth grade public school children in Patras, Greece. Sample sizes in 1978, 1991, and 1998 were 3735, 2952 and 3397 children and response rates were 80.4%, 81.9%, and 90.6%, respectively. Prevalence of current, non-current, and lifetime asthma or recurrent wheezing was determined by parental questionnaire. Personal communication with the parents of asthmatic children in 1991 and 1998 provided data on lost schooldays. RESULTS: Prevalence rates of current asthma or wheezing in 1978, 1991, and 1998 were 1.5%, 4.6%, and 6.0%, respectively (1978-91: p=0.01, 1991-98: p=0.02, 1978-98: p=0.03). Lifetime prevalences of asthma or wheezing in 1991 and 1998 were 8.0% and 9.6%, respectively (p=0.03). Current diagnosed asthma increased proportionally to diagnosed wheezing during 1991-98. The number of schooldays lost in the previous 2 years because of asthma did not change (p>0.1) between 1991 (0.31 per child) and 1998 (0.34 per child). CONCLUSIONS: Our results support a true increase in the prevalence of current and lifetime asthma in the last 20 years among pre-adolescent children in Patras, Greece.

Asthma↗
PubMed1993

Time trends and seasonal variation in hospital admissions for childhood asthma in the Athens region of Greece: 1978-88.

BACKGROUND: The aim of the study was to determine the trend and seasonal variation in hospital admissions for childhood asthma in the Athens region of Greece. METHODS: Data were obtained from hospital registries of the three main children's hospitals in Athens between 1978 and 1988. Children admitted with the diagnosis of asthma, asthmatic bronchitis, or wheezy bronchitis were included. The data were expressed as admission rates per 100,000 of the same aged population. RESULTS: There were 9795 admissions for asthma over the 11 years and the admission rate rose by 294%. Admissions among those aged 0-4 and 5-14 rose by 272% and 379% respectively. Monthly admissions showed a pronounced seasonal variation, rising during the cold damp period in the 0-4 age group, but peaking around May in the 5-14 age group. CONCLUSIONS: These findings suggest that hospital admissions due to asthma in the Athens region have increased considerably since 1978, and that clear cut seasonal variations exist which are specific to age.

Adolescent↗
PubMed1993

Sensitization of asthmatic children to common environmental allergens according to their residence.

The medical records of 974 asthmatic children aged 1-14 years (mean 8.7 +/- 3.9 years) who had been evaluated with skin prick tests (SPT) in two referral Children's Hospitals in Athens from 1975 to 1987 were analyzed. The children were grouped according to their residence into groups from urban area (UR), rural area (RU), and coastals (CO). The prevalence of positive SPT and the sensitizing allergens according to the residential area and the family atopic history were considered. It was found that 662/974 (68%) children had positive SPT with 63.6%, 70.7%, and 80.4% in UR, RU, and CO respectively. There was a significant difference in the prevalence of positive SPT between UR and CO. A positive family atopic history was more often accompanied by positive SPT in UR only. Sensitization to grass pollens was noted with higher prevalence in UR. The house dust mite Dermatophagoides pteronyssinus sensitization was more prevalent in CO. Our results support the notion that the environment can influence the prevalence of sensitization to common environmental antigens, the kind of sensitizing allergen, and the expressiveness of the genetic factor with regard to development of atopic asthma.

Adolescent↗
PubMed1991

Unexpected side-effects of inhaled steroids: a case report.

An asthmatic child is presented who developed a cushingoid appearance with evidence of adrenal suppression and growth impairment while on low dose inhaled topical steroids. When the inhaled steroids were replaced by inhaled sodium cromoglycate his adrenal function recovered while his appearance and growth returned to normal. This report indicates that there are some children who are at risk of developing side-effects on doses of inhaled topical steroids normally considered to be entirely safe.

Administration, Inhalation↗
PubMed1991

Ciliary beat frequency in newborn infants.

The ciliary beat frequencies of 31 newborns and 14 adults were measured in vitro by a photodiode method at body temperature (37 degrees C). The mean (SD) neonatal ciliary beat frequency (12.7 (0.82) Hz) was faster than that in adults (11.1 (0.84) Hz) (p less than 0.01). Increased ciliary beat frequency may be advantageous during the neonatal period.

Adult↗
PubMed1990

Adrenal function in asthma.

A dose dependent suppression of daily cortisol excretion was shown in 25 children with asthma being treated with beclomethasone dipropionate. Cortisol metabolites tended to occur below the normal range when doses of beclomethasone of more than 400 micrograms/m2/day were given. Androgen excretion below the normal range was apparent in asthmatic children aged 8-13 years regardless of whether they were receiving inhaled steroids. This may be the reason for growth delay often seen in asthmatic children. These side effects of beclomethasone are not enough reason to discourage its prescription for the treatment of asthma, but endocrine assessment is desirable when the dose exceeds 400 micrograms/m2/day.

Adolescent↗
PubMedDate not supplied

Masked myoclonus in corticobasal degeneration: neurophysiological study of a case.

A single case study of a 58 year-old male with right asymmetric apraxia and akinetic-rigid syndrome is described. Brainimaging scans (MRI, SPECT) indicated asymmetric cortical atrophy compatible with the diagnosis of Corticobasal Degeneration. Reflex myoclonus was absent and myoclonic discharges only appeared in response to pharmacological treatment of limb dystonia and rigidity. Electromyographic evidence of jerky movements was recorded only in the affected right hand and forearm after muscle relaxation, and myoclonus was not preceded by an EEG paroxysm. The cortical components of the correspondent SEPs were not increased in amplitude while LLRs recordings showed a late response over the muscles of the affected side. Furthermore, the duration of post MEP silent period was bilaterally reduced. This single case study report points out that sometimes myoclonus in Corticobasal Degeneration can be masked by the presence of increased muscle tone.

Apraxias↗