Biomedical subjects

N Agar

Publications and source records attributed to N Agar.

6 recordsLinked to original sources

PubMed2001

Script knowledge after severe traumatic brain injury.

Severe diffuse traumatic brain injury (TBI) may impair the performance of daily-life complex activities. The aim of the present study was to assess whether these difficulties are related to a representational impairment of action knowledge. Two tasks requiring the manipulation of scripts were used. The first (script reconstitution) required subjects to sort cards describing actions belonging to 4 different scripts, presented in a random order. The second (script generation) required subjects to generate actions belonging to a given script. The results showed that TBI patients had preserved access to goal representation and action knowledge. However, they demonstrated (1) significant impairments when they had to deal with simultaneous competing sources of information and (2) a lack of inhibitory control on routine overlearned skills. Patients' performance was significantly correlated with behavioral modifications in everyday life. These data suggest that action impairment in severe TBI patients cannot be attributed to an impairment of action knowledge per se. As previously suggested by Schwartz et al., a restriction of limited-capacity processing resources may account for the observed deficits.

Activities of Daily Living↗

PubMed1995

[Effect of modafinil in narcoleptic patients. Electrophysiologic and psychometric studies].

Clinical efficiency of Modafinil was clearly demonstrated in narcoleptic patients but only a few electrophysiological studies were carried out to confirm these observations. Since Modafinil did not change the propensy to fall asleep, the aim of this work was to study maintenance of wakefulness and performance levels in treated narcoleptic patients. Of the 16 treated patients, 12 responded as expected to Modafinil. These 12 patients were studied. After a one night polysomnography, electrophysiological tests included: baseline spectral analysis, maintenance of wakefulness tests carried out respectively eyes open in diffused light and eyes closed in darkness during which sleep latency, duration of test and changes in the theta/alpha ratio were measured. Psychometric performances were evaluated using verbal or non verbal tests: visual and auditory reaction time tests. Trail Making Test, Stroop, verbal Fluency and WAIS-R. Modafinil improved the ability of narcoleptic patients to remain awake only when the situation or the environmental conditions were favorable. Some psychometric performances also trended towards on improvement.

Adult↗

PubMed1995

Fibrolamellar hepatocellular carcinoma "it is not a ordinary case for Mediterranean countries".

The fibrolamellar variant of hepatocellular carcinoma (HCC) is an uncommon tumour with distinctive clinical and histological features. Although the first case of fibrolamellar hepatocellular carcinoma (FI-HCC) was described by Edmondson in 1956, and later confirmed in five patients by Peters, the majority of reports followed those of Berman et al. and Craig et al. A case of FI-HCC, which is rarely diagnosed in Mediterranean countries including Turkey, is presented in the following report.

Adult↗

PubMed1991

Auditory evoked responses (AER) and augmenting-reducing phenomenon in patients with progressive supranuclear palsy (PSP).

Variations in amplitude and latency of P1, N1 and P2 waves of AER induced by increasing the stimulus intensity (augmenting-reducing) were measured in PSP patients and compared to those observed in normal subjects. The studied population included 17 patients (10 male, 7 female, mean age 66 +/- 8 yr) with a typical PSP symptomatology and 17 normal subjects (10 male, 7 female, mean age 66 +/- 9 yr). All subjects from both the groups showed a normal auditory threshold (less than 30 db SPL or a moderately increased threshold never exceeding 10 db SPL). Nine patients had normal BAER; 4 patients showed an abnormal III wave; 3 patients showed an abnormal V wave. One patient had a poorly individualized BAER. Latencies and amplitudes of P1, N1 and P2 waves derived from Cz and Fz (linked ear reference) were studied with 50, 60, 70 and 80 db intensities and for each patient slopes of amplitude-stimulus intensity and latency-stimulus intensity curves were studied. Although patients showed decreased AER amplitudes, the augmenting-reducing phenomenon was not different from controls regarding either latency or amplitude changes with increasing stimulus intensity. Previous studies had established a negative correlation between the augmenting-reducing responses and HVA levels in the cerebrospinal fluid (CSF). Similarity of augmenting-reducing mechanisms in PSP and normal subjects favors the hypothesis of unimpaired mesocortical and mesolimbic dopaminergic pathways in PSP. This hypothesis is also supported by postmortem studies using biochemical markers.

Aged↗

PubMed1989

Effect of age on auditory evoked responses (AER) and augmenting-reducing.

Auditory evoked responses (AER) were obtained from Cz and Fz in 30 adults (14 male, 16 female) from 20-80 years old. Sound bursts (1000 Hz-200 msec) of four different intensities were used. Peak to trough amplitudes of P1N1 and N1P2 and latencies of P1, N1 and P2 peaks were measured with increasing stimulus intensity and slopes of amplitude - intensity and latency - intensity curves were analysed for assessment of an age effect. The main result is that the increase in P1N1 amplitude with increasing stimulus intensity is more pronounced in older persons. Previous studies have established a negative correlation between the augmenting-reducing responses and HVA levels in the CSF (with lower amounts of HVA in the CSF of "augmenters"). Decreased dopamine metabolism in old subjects could account for our results, so further studies should focus on patients with pathological dopamine deficiencies.

Acoustic Stimulation↗

PubMed1985

Hyperlipidemic dementia.

The dementia of a patient with hyperlipidemia improved dramatically on treatment with diet and fenofibrate. Rheologic study showed an abnormality of rouleaux disaggregation, and this disappeared as plasma lipid levels fell and mental state improved.

Clofibrate↗