Biomedical subjects

Caterina De Leo

Publications and source records attributed to Caterina De Leo.

5 recordsLinked to original sources

PubMed2005

Stroop interference task and single-photon emission tomography in anorexia: a preliminary report.

OBJECTIVE: The aim of this preliminary study was to investigate the physiologic substrate of executive function in anorexia nervosa (AN) by assessing the relation between brain perfusion and Stroop interference task (SIT). METHOD: The classical SIT test and brain single-photon emission tomography (SPET) were evaluated in 16 AN females (mean age = 23.69 +/- 8.68 years; mean body mass index [BMI] = 16.19 +/- 1.53 kg/m2). The relation between the two examinations was searched by statistical parametric mapping (SPM 99) with a height threshold of p = .001. RESULTS: An abnormally low or a borderline SIT value was found in 25% of patients. A significant correlation between the SIT score and brain perfusion was found in the superior frontal gyrus of both hemispheres (Brodmann's area [BA] 6 in both hemispheres and BA 8 in the right hemisphere). No correlation was found in the anterior cingulate gyrus. CONCLUSION: BA 6 and BA 8 and the anterior cingulate are believed to be the basis of both error detection and immediate correction. Activity of BA 6 and BA 8 reflects this executive task in AN patients as well, whereas the lack of correlation in the anterior cingulate may suggest its blunted activity in AN patients, similarly to what is shown in other conditions characterized by impaired executive function, such as patients with depression, patients with schizophrenia, and abstinent drug abusers. However, these findings should still be quoted as preliminary, given some limitations of the study design, such as the lack of a control group, and the unfeasibility of controlling some relevant confounding variables, such as psychiatric comorbidity, medication, and the time interval between examinations, mainly deriving from the relatively few patients studied.

Adolescent↗

PubMed2005

Resting SPECT-neuropsychology correlation in very mild Alzheimer's disease.

OBJECTIVE: To investigate the relationships between brain function and some of the most frequently impaired cognitive domains in the first stages of Alzheimer's disease (AD), we searched for correlation between the scores on 3 neuropsychological tests and brain perfusion, assessed by single photon emission computed tomography (SPECT) in patients with very mild AD. METHODS: Twenty-nine consecutive outpatients (mean age 78.2+/-5.5) affected by probable AD in the very mild phase (i.e. with a score > or =20 on the mini-mental state examination, MMSE) underwent brain SPECT with (99m)Tc-ethylcisteinate dimer. For correlative purposes, word list learning (by the selective reminding test, SRT), constructional praxis test (CPT) and visual search test (VST) were chosen a priori out of an extended battery employed to diagnose AD at first patient evaluation. Voxel-based correlation analysis was achieved by statistical parametric mapping (SPM99) with a height threshold of P=0.005. Age, years of education and the MMSE score were inserted in the correlative analysis as confounding variables. RESULTS: The SRT score showed correlation with brain perfusion in 3 clusters of the left hemisphere, including the post-central gyrus, the parietal precuneus, the inferior parietal lobule and the middle temporal gyrus, and in one cluster in the right hemisphere including the middle temporal gyrus and the middle occipital gyrus. The CPT score was significantly correlated with brain perfusion in the parietal precuneus and the posterior cingulate gyrus in the left hemisphere, whereas the VST score gave a significant correlation with brain perfusion in a left cluster including the parietal precuneus and the superior temporal gyrus. CONCLUSIONS: Cognitive impairment in very mild AD is reflected by brain dysfunction in posterior associative areas, with peculiar topographical differences proper of each domain. The parietal precuneus was a common site of correlation of all 3 neuropsychological tests. This region, together with the posterior cingulate and the superficial posterior temporal-parietal cortex, is thought to be affected by disconnection from the mesial temporal lobe, besides being directly affected by increased oxidative stress and by atrophy as well. The impairment of these areas is thought to contribute to cognitive decline in verbal memory, constructional praxis and visual sustained attention which are indeed among the earliest signs of cognitive impairment in AD. SIGNIFICANCE: Assessing the relationships between neuropsychology and brain functional imaging is a key approach to clarify the pathophysiology of cognitive failure in AD; the specificity of these findings in AD remains to be proven through comparison with correlation achieved in matched controls.

Aged↗

PubMed2004

Quantitative EEG and perfusional single photon emission computed tomography correlation during long-term donepezil therapy in Alzheimer's disease.

OBJECTIVE: There is an increasing interest in the effects of the acetylcholinesterase inhibitors (AChEIs) in Alzheimer's disease (AD), as investigated by means of objective, neurophysiological tools. In an open-label study, we evaluated the neurophysiological effects of chronic administration of donepezil to AD patients, by means of a correlative approach between quantitative EEG (qEEG) and perfusional brain single photon emission computed tomography (SPECT). METHODS: Sixteen patients (mean age: 74.8+/-7.9 years) with mild to moderate AD (MMSE score >13, mean: 20.7+/-4.6) underwent qEEG and SPECT examinations at the time of diagnosis (t0) and after approximately 1 year of donepezil therapy (t1). The brain SPECT (99mTc-hexamethylpropyleneamine oxime) was performed by means of a high-resolution SPECT camera; the qEEG was recorded from 19 scalp electrodes by average reference and digitized at 512 Hz. The mean frequency (MF) value of the mean power spectrum (fast Fourier transform) from 4 brain regions (one frontal and one temporal-parietal in each hemisphere) was chosen for statistical analysis. Changes in MMSE score and qEEG-MF values between t0 and t1 were assessed by analysis of variance. SPECT differences between t0 and t1, as well as the relationships between SPECT and qEEG changes, were assessed by statistical parametric mapping (SPM 99; height threshold: P=0.001 at cluster level). RESULTS: Between t0 and t1, the MMSE score significantly (P<0.05) decreased (from 20.7+/-4.64 to 19.1+/-5.09; 95% confidence interval: 1.14) and qEEG was unchanged. There was no regional perfusion decrease; a small area of relative perfusion increase was observed, including the right occipital cuneus and the left lingual gyrus. A positive correlation was found between the right frontal MF and brain perfusion in the left superior parietal lobule. A post hoc SPM analysis (height threshold: P=0.01) showed a positive correlation between brain perfusion and each of the 4 qEEG MF values in the left parietal lobe, including the precuneus, the superior parietal lobule, and the post-central gyrus. CONCLUSIONS: The posterior parietal region, which is involved in memory and attention, is often affected by hypoperfusion in AD, as a likely consequence of disconnection from the atrophic mesial temporal cortex. Metabolic activation induced by AChEIs may especially influence this disconnected but still not grossly impaired area, which could be one of the pathophysiological substrates of the cognitive effects of AChEIs. The modest topographical sensitivity of qEEG, reflecting the rather diffuse changes in AD, is further confirmed.

Aged↗

PubMed2002

Effects of long-term Donepezil therapy on rCBF of Alzheimer's patients.

BACKGROUND: The recent introduction of acetylcholinesterase inhibitors (AChEIs) therapy for Alzheimer's Disease (AD) has led to the need to assess the brain's response to the therapy on an objective, neurophysiological basis. Brain perfusion single photon emission computed tomography (SPECT) was used in an open-label study to evaluate the effect of chronic Donepezil administration to a group of patients affected by mild to moderate AD, compared to a group of AD patients not receiving AChEIs and kept under observation for a similar period. METHODS: Twenty-five consecutive patients with probable AD (National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria) (19 women, 6 men; mean age: 74.2+/-7.2; mean Mini-Mental State Examination score, MMSE: 19.8+/-3.5) underwent (t0) brain SPECT with 99mTc-hexamethylpropylene-amine-oxime by a brain-dedicated, high-resolution camera and were re-evaluated (t1) after 11+/-2.6 months of chronic Donepezil administration (5mg/day) (treated group). Thirteen AD patients (9 women, 4 men, mean age: 71.4+/-5.7, MMSE score: 20.6+/-3.5) were not treated with AChEIs and served as controls (untreated group). They were subjected to the same evaluation after 13+/-1.4 months as the treated group. Statistical parametric mapping (SPM) was employed to analyse SPECT findings. RESULTS: The MMSE score declined significantly (P<0.01) from t0 to t1 both in untreated (from 20.6+/-3.5 to 17.8+/-4.4) and in treated (from 19.8+/-3.5 to 17.8+/-4.1) group. At t(0), the untreated group showed higher regional cerebral blood flow (rCBF) than the treated group in a frontal and a frontal-parietal region of the left hemisphere. Between t0 and t1, significant rCBF reduction was observed in the temporal lobe and occipital-temporal cortex of the left hemisphere in the untreated group, whereas no significant change was observed in the treated group. The rCBF of the two groups did not significantly differ at t1. By covariate SPM analysis between t0 and t1 in treated patients, MMSE score changes correlated significantly with rCBF changes in a large left frontal-temporal region. CONCLUSIONS: Brain perfusion is preserved in AD patients undergoing chronic Donepezil therapy while it is reduced in untreated patients. SPECT is a promising tool with which to assess the impact of AChEI therapy on brain functioning of AD patients.

Aged↗

PubMed2002

Quantitative EEG changes in Alzheimer patients during long-term donepezil therapy.

Twenty patients affected with probable mild-to-moderate Alzheimer's disease (AD; NINCDS-ADRDA criteria; 14 women and 6 men, mean age 75.2 +/- 7.1 years) who regularly received an oral acetylcholinesterase inhibitor (AChEI; donepezil 5 mg/day; Dz group) were compared with a control group of 11 AD patients (6 women and 5 men, mean age 73.5 +/- 6.0 years) diagnosed and followed up in the pre-AChEIs era (C group). At basal evaluation (t(0)), the 2 groups were comparable for age, education, and severity of disease (Global Deterioration Scale). All patients underwent quantitative EEG (qEEG, average reference, 10-20 International System), and were reexamined about 1 year later (t(1); i.e., after 12.3 +/- 3.6 months the Dz group, and after 13.7 +/- 3.9 months the C group). Log-transformed values of two qEEG bands, i.e. 2-6 and 6.5-12 Hz, were averaged between adjacent channels (frontal F3 and F7, F4 and F8; parietotemporal P3 and T7, P4 and T8) to obtain a qEEG ratio (6.5-12/2-6 Hz.) from one frontal and one temporoparietal region in each hemisphere. Neuropsychological impairment was summarized by the Mini-Mental Status Examination (MMSE). At t(0), both the MMSE score and the qEEG ratio values were somewhat higher in the C than in the Dz group, although nonsignificantly. Between t(0) and t(1), the MMSE score decreased significantly (p < 0.01) more in the C group (-4.36 +/- 2.25) than in the Dz group (-1.45 +/- 2.16), as did the qEEG ratio in the right frontal region (p < 0.01), whereas in the left frontal region the significance level was not reached (p = 0.02). Between t(0) and t(1), the qEEG ratio difference in both frontal regions and in the right temporoparietal region significantly correlated with the MMSE difference (p < 0.01), but neither with time between examinations nor with the difference on the Visual Search Test score. Long-term treatment with Dz led to a lesser deterioration of qEEG, paralleling a milder neuropsychological decline. The effect was significant in frontal regions, possibly because they are relatively spared during the mild-to-moderate phases of the disease.

Aged↗