The Experts below are selected from a list of 3531 Experts worldwide ranked by ideXlab platform
Barbara J Sahakian - One of the best experts on this subject based on the ideXlab platform.
-
Idazoxan potentiates rather than antagonizes some of the cognitive effects of clonidine
Psychopharmacology, 1999Co-Authors: Hugh Middleton, Barbara J Sahakian, A. Sharma, D. Agouzoul, Trevor W RobbinsAbstract:Several investigations have revealed substantial influences of pharmacological manipulation of central noradrenergic activity upon performance in cognitive tests sensitive to Frontal Lobe Dysfunction. They suggest a significant role for the noradrenergic coeruleo-cortical projection in cognitive function but conflicting findings and the complex pharmacology of adrenoceptor agents make it difficult to be precise about underlying mechanisms. In order to clarify these we have compared the effects of an α1/α2-adrenoceptor agonist, clonidine, an α2-adrenoceptor antagonist, idazoxan, and these agents in combination. Three groups of healthy volunteers were used to investigate the effects of these noradrenergic manipulations upon performance of tasks from the CANTAB test battery known to be sensitive to Frontal Lobe Dysfunction. Previously reported effects of clonidine upon sustained visual attention and upon session-to-session improvement were replicated. Furthermore, idazoxan inhibited the hypotensive effect of clonidine. Idazoxan had no overall effect on performance of any of the tests but did inhibit session-to-session improvement in performance of a planning task, attentional set shifting and sustained visual attention. Rather than leading to the anticipated mutual antagonism of effects, combining clonidine and idazoxan led to a wider and more striking range of cognitive impairments. These results are discussed alongside findings which support a role for imidazoline (I1) receptors in blood pressure control, where clonidine and idazoxan are antagonistic, and evidence of less potent antagonism at somato-dendritic α2-adrenoceptors in the locus coeruleus.
-
the effects of chronic administration of hydrocortisone on cognitive function in normal male volunteers
Psychopharmacology, 1999Co-Authors: Allan H Young, Barbara J Sahakian, Trevor W Robbins, P.j. CowenAbstract:Rationale: Corticosteroids are elevated in certain neuropsychiatric disorders and this may contribute to the neuropsychological impairments reported in these disorders. Objective: To examine the effects of hydrocortisone on learning, memory and executive function. Methods: Hydrocortisone 20 mg was administered twice daily for 10 days to normal male volunteers in a randomized, placebo control, crossover, within-subject design. Learning, memory and executive function were measured using selected subtests from the Cambridge Neuropsychological Test Automated Battery. Results: Hydrocortisone caused impairments of visuo-spatial memory. These included increased within search errors and impaired use of strategies on the spatial working memory subtest. In addition, administration of hydrocortisone was associated with more errors in the paired associate learning subtest, although no effect was found on the Tower of London. Hydrocortisone speeded response latencies in certain tests (pattern and spatial recognition memory). Conclusion: These results indicate that chronic administration of hydrocortisone leads to deficits in certain tests of cognitive function sensitive to Frontal Lobe Dysfunction and may contribute to the cognitive impairment reported in certain neuropsychiatric disorders.
-
a study of performance on tests from the cantab battery sensitive to Frontal Lobe Dysfunction in a large sample of normal volunteers implications for theories of executive functioning and cognitive aging
Journal of The International Neuropsychological Society, 1998Co-Authors: Trevor W Robbins, Barbara J Sahakian, Merle James, Adrian M Owen, Andrew David Lawrence, Lynn Mcinnes, Patrick RabbittAbstract:Several tests from the CANTAB neuropsychological test battery previously shown to be sensitive to Frontal Lobe Dysfunction were administered to a large group of normal volunteers (N = 341) ranging in age from 21 to 79 years. The main tests included a computerized form of the Tower of London test of planning, a self-ordered spatial working memory task, and a test of attentional set formation and shifting. A computerized form of the Corsi spatial span task was also given. Age-related graded declines in performance were seen, sometimes in a discontinuous manner, especially for the attentional set shifting task (at the extradimensional shift stage). Patterns of deficits reminiscent of Frontal Lobe or basal ganglia damage were observed in the oldest age group (74–79). However, overall the data were only partially consistent with the hypothesis that Frontal Lobe functions are the most sensitive to effects of aging. Factor analyses showed that performance in the executive tests was not simply related to a measure of fluid intelligence, and their performance had a factor loading structure distinct from that for the CANTAB tests of visual memory and learning previously administered to the same sample. Finally, only limited support was found for the hypothesis that cognitive aging depends on slowed information processing. (JINS, 1998, 4, 474–490.)
-
effects of methylphenidate on spatial working memory and planning in healthy young adults
Psychopharmacology, 1997Co-Authors: Rebecca Elliott, Barbara J Sahakian, Keith Matthews, A Bannerjea, J Rimmer, Trevor W RobbinsAbstract:Previous studies of the effects of the psychomotor stimulant, methylphenidate, have concentrated on vigilance and reaction time tasks. In this study, the effects of methylphenidate on more complex aspects of cognition were studied using tasks from the CANTAB battery and related tests which have been shown to be sensitive to Frontal Lobe Dysfunction. Twenty-eight young healthy men participated in a counterbalanced, double-blind, placebo-controlled study of the effects of methylphenidate. Cognitive assessment included tests of spatial working memory, planning, verbal fluency, attentional set-shifting and sustained attention. Methylphenidate had significant effects on performance of the tests of spatial working memory and planning but not on the attentional and fluency tests. When the drug was taken on the first test session, performance on the spatial tests was enhanced by the drug compared to placebo. However, when the drug was taken second, performance accuracy was impaired whereas response latencies were decreased. These results are consistent with a hypothesis that methylphenidate influences performance in two conflicting ways; enhancing executive aspects of spatial function on novel tasks but impairing previously established performance. This pattern of effects is discussed within the framework of dual, interacting arousal mechanisms.
-
specific cognitive deficits in tests sensitive to Frontal Lobe Dysfunction in obsessive compulsive disorder
Psychological Medicine, 1996Co-Authors: David Veale, Barbara J Sahakian, A M Owen, I M MarksAbstract:Forty patients with obsessive-compulsive disorder (OCD) were compared to matched healthy controls on neuropsychological tests which are sensitive to Frontal Lobe Dysfunction. On a computerized version of the Tower of London test of planning, the patients were no different from healthy controls in the accuracy of their solutions. However, when they made a mistake, they spent more time than the controls in generating alternative solutions or checking that the next move would be correct. The results suggest that OCD patients have a selective deficit in generating alternative strategies when they make a mistake. In a separate attentional set-shifting task, OCD patients were impaired in a simple discrimination learning task and showed a continuous cumulative increase in the number who failed at each stage of the task, including the crucial extradimensional set shifting stage. This suggests that OCD patients show deficits in both acquiring and maintaining cognitive sets. The cognitive deficits in OCD may be summarized as: (i) being easily distracted by other competing stimuli; (ii) excessive monitoring and checking of the response to ensure a mistake does not occur; and (iii) when a mistake does occur, being more rigid at setting aside the main goal and planning the necessary subgoals. Both studies support the evidence of fronto-striatal Dysfunction in OCD and the results are discussed in terms of an impaired Supervisory Attentional System.
Carole Azuar - One of the best experts on this subject based on the ideXlab platform.
-
Acute Frontal Lobe Dysfunction Following PreFrontal Low-Frequency Repetitive Transcranial Magnetic Stimulation in a Patient with Treatment-Resistant Depression
Frontiers in Psychiatry, 2017Co-Authors: Guilhem Carle, Mehdi Touat, Nicolas Bruno, Damien Galanaud, Charles-siegfried Peretti, Antoni Valero-cabré, Richard Levy, Carole AzuarAbstract:The potential of repetitive transcranial magnetic stimulation (rTMS) to treat numerous neurological and psychiatric disorders has been thoroughly studied for the last two decades. Here, we report for the first time, the case of a 65-year-old woman suffering from treatment-resistant depression who developed an acute Frontal Lobe syndrome following eight sessions of low-frequency rTMS (LF-rTMS) to the right dorsolateral preFrontal cortex while also treated with sertraline and mianserin. The pathophysiological mechanisms underlying such an unexpected acute Frontal Lobe Dysfunction are discussed in relation to the therapeutic use of LF-rTMS in combination with pharmacotherapy in depressed patients.
Laura Bellodi - One of the best experts on this subject based on the ideXlab platform.
-
Frontal Lobe Dysfunction in pathological gambling patients
Biological Psychiatry, 2002Co-Authors: Paolo Cavedini, Giovanna Riboldi, Roberto Keller, Arcangela Dannucci, Laura BellodiAbstract:Abstract Background: Limited data are available about the validity of the diagnosis of pathological gambling (PG) and about the etiology and the efficacy of different treatment strategies of this disorder; however, similarities in decision-making behavior between PG patients and patients with ventromedial preFrontal cortex lesions suggest a possible implication of these areas in the pathophysiology of this disorder, as in obsessive-compulsive disorder, in which the decision-making impairment is significantly associated with response to serotonin reuptake inhibitor treatment. Nevertheless, several studies have shown that decision-making functioning is also impaired in drug-addicted patients who have shown abnormalities in ventromedial preFrontal cortex during functional neuroimaging studies. Methods: We assessed the decision-making function mediated by the ventromedial preFrontal cortex in 20 PG patients and 40 healthy control (HC) subjects using the Gambling Task, which simulates real-life decision-making, testing the ability to balance immediate rewards against long-term negative consequence. Results: Significant differences were found in Gambling Task performance between HC subjects and PG patients, who showed a specific decision-making profile across the sequence of the game. The dissimilarity does not appear to depend on the basic cognitive function deficit of the PG group. Conclusions: These data seem to suggest the existence of a link between PG and other disorders (i.e., obsessive-compulsive disorder and drug addiction) all having diminished ability to evaluate future consequences, which may be explained at least in part by an abnormal functioning of the orbitoFrontal cortex.
-
decision making heterogeneity in obsessive compulsive disorder ventromedial preFrontal cortex function predicts different treatment outcomes
Neuropsychologia, 2002Co-Authors: Paolo Cavedini, Giovanna Riboldi, Arcangela Dannucci, Patrizia Belotti, Michele Cisima, Laura BellodiAbstract:Certain clinical aspects of patients with Obsessive-Compulsive Disorder (OCD) appear similar to those of patients with damage to the ventromedial sector of the preFrontal cortex. The hypothesis for the involvement of the Frontal region in OCD is also supported by neuropsychological findings. Building on this evidence, we assessed the performance of a group of 34 OCD patients on a measure indexing with orbitoFrontal cortex functioning and compared it with the performance of two other subject groups, one consisting of 34 healthy control subjects and the other 16 patients with panic disorder. All study subjects performed a neuropsychological task, which is sensitive to Frontal Lobe Dysfunction and simulating real-life decision-making. Significant differences were found between the neuropsychological profiles of the OCD and of other groups, pointing to a possible specificity of decision-making deficit in OCD. Comparison of the performance of the OCD patients grouped according to response to antiobsessive drug treatment showed that poor neuropsychological task performance predicted poor outcome of pharmacological treatment. Task behavior did not correlate with severity of illness or demographic characteristics of the subjects. Results support the role of the ventromedial preFrontal cortex in OCD.
-
Frontal Lobe Dysfunction in obsessive compulsive disorder and major depression a clinical neuropsychological study
Psychiatry Research-neuroimaging, 1998Co-Authors: Paolo Cavedini, Stefano Ferri, S Scarone, Laura BellodiAbstract:Neuropsychological findings support a hypothesized relationship between obsessive-compulsive disorder (OCD) and the Frontal Lobe. The aim of the present study was to compare findings of neuropsychological tests of Frontal Lobe function in 28 OCD patients and 29 patients with major depressive disorder (MDD), all diagnosed according to DSM III-R criteria. The patient groups were homogeneous for educational level, handedness, duration of illness, and sex distribution. All 57 subjects received a battery of tests sensitive to Frontal Lobe Dysfunction as well as the Wechsler Memory Scale (WMS). Clinical symptomatology in the MDD and OCD groups was assessed with the Hamilton Rating Scale for Depression and the Yale-Brown Obsessive-Compulsive Scale, respectively. The only significant difference between the two diagnostic groups for any of the neuropsychological indices, with age as a covariate, was in the Object Alternation Test, in which OCD patients had a significantly higher number of perseverative responses. Test performances were not correlated with clinical symptomatology or severity of illness. Our preliminary results confirm the hypothesis that there is a selective impairment of orbito-Frontal cortex in OCD and seem to exclude the existence of specific Frontal Lobe Dysfunction in MDD, even though the two disorders show clinical similarities.
-
Frontal Lobe Dysfunction in schizophrenia and obsessive compulsive disorder a neuropsychological study
Brain and Cognition, 1995Co-Authors: Massimo Abbruzzese, Laura Bellodi, Stefano Ferri, S ScaroneAbstract:Abstract Converging evidence suggests there is a specific role of dorso-lateral-preFrontal cortex (DLPC) in schizophrenic disorders and of orbite-Frontal cortex (OFC) in obsessive-compulsive disorder (OCD). Here, 25 schizophrenic and 25 OCD patients were evaluated with Wisconsin Card Sorting Test and Object Alternation Test; neuropsychological tools sensitive to DLPC and OFC damage, respectively; and compared with 25 subjects of a control group. Moreover, they all underwent Weigls Sorting Test and the Word Fluency Test to assess global Frontal functioning. The results indicated a DLPC deficit in schizophrenia and an OFC involvement in OCD. These data suggest that functional disorders of the central nervous system can be explored with neuropsychological instruments.
Bruno Dubois - One of the best experts on this subject based on the ideXlab platform.
-
Frontal assessment battery and differential diagnosis of frontotemporal dementia and alzheimer disease
JAMA Neurology, 2004Co-Authors: Andrea Slachevsky, B Pillon, Juan Manuel Villalpando, Marie Sarazin, Valerie Hahnbarma, Bruno DuboisAbstract:Background The different distribution of pathologic features in frontotemporal dementia (FTD) and Alzheimer disease (AD) predicts a predominant dysexecutive syndrome in FTD. The Frontal Assessment Battery (FAB) has previously been validated in diseases associated with a Frontal Lobe Dysfunction. Objective To evaluate the sensitivity of the FAB to differentiate FTD and AD. Design Comparison study. Setting Memory Clinic of the Salpetriere Hospital, Paris, France. Patients Twenty-six patients with FTD and 64 patients with AD. Main Outcome Measures Comparison of FAB and Mini-Mental State Examination (MMSE) scores between patients with FTD and those with AD. Results The mean ± SD FAB scores significantly differed between patients with FTD (7.6 ± 4.2) and those with AD (12.6 ± 3.7) ( P Conclusions The FAB takes less than 10 minutes to administer and provides an objective measure to distinguish FTD from AD in mildly demented patients.
-
the fab a Frontal assessment battery at bedside
Neurology, 2000Co-Authors: Bruno Dubois, Andrea Slachevsky, Irene Litvan, B PillonAbstract:Objective: To devise a short bedside cognitive and behavioral battery to assess Frontal Lobe functions. Methods: The designed battery consists of six subtests exploring the following: conceptualization, mental flexibility, motor programming, sensitivity to interference, inhibitory control, and environmental autonomy. It takes approximately 10 minutes to administer. The authors studied 42 normal subjects and 121 patients with various degrees of Frontal Lobe Dysfunction (PD, n = 24; multiple system atrophy, n = 6; corticobasal degeneration, n = 21; progressive supranuclear palsy, n = 47; frontotemporal dementia, n = 23). Results: The Frontal Assessment Battery scores correlated with the Mattis Dementia Rating Scale scores (rho = 0.82, p p p p Conclusion: The Frontal Assessment Battery is easy to administer at bedside and is sensitive to Frontal Lobe Dysfunction.
-
relation of anosognosia to Frontal Lobe Dysfunction in alzheimer s disease
Journal of Neurology Neurosurgery and Psychiatry, 1994Co-Authors: A Michon, B Pillon, Bernard Deweer, Y Agid, Bruno DuboisAbstract:A self-rating scale of memory functions was administered to 24 non-depressed patients with probable Alzheimer's disease, divided into two groups according to the overall severity of dementia (mild, mini-mental state (MMS) > 21; moderate, MMS between 10 and 20). These groups did not significantly differ in their self-rating of memory functions. The same questionnaire was submitted to a member of each patient's family, who had to rate the patient's memory. An "anosognosia score" was defined as the difference between patient's and family's ratings. This score was highly variable, and covered, in the two groups, the full range between complete awareness of deficits and total anosognosia. Correlations between the anosognosia score and several neuropsychological data were searched for. No significant correlation was found with either the Wechsler memory scale, the MMS, or linguistic abilities and gestures. In contrast, this score was highly correlated with the "Frontal score", defined as the sum of scores on the Wisconsin card sorting test (WCST), verbal fluency, Luria's graphic series, and "Frontal behaviours" (prehension, utilisation, imitation behaviours, inertia, indifference). Among these tests of executive functions, the highest correlation with the anosognosia score was obtained on the WCST. This suggests that anosognosia in Alzheimer's disease is not related to the degree of cognitive deterioration but results, at least in part, from Frontal Dysfunction.
B Pillon - One of the best experts on this subject based on the ideXlab platform.
-
Frontal assessment battery and differential diagnosis of frontotemporal dementia and alzheimer disease
JAMA Neurology, 2004Co-Authors: Andrea Slachevsky, B Pillon, Juan Manuel Villalpando, Marie Sarazin, Valerie Hahnbarma, Bruno DuboisAbstract:Background The different distribution of pathologic features in frontotemporal dementia (FTD) and Alzheimer disease (AD) predicts a predominant dysexecutive syndrome in FTD. The Frontal Assessment Battery (FAB) has previously been validated in diseases associated with a Frontal Lobe Dysfunction. Objective To evaluate the sensitivity of the FAB to differentiate FTD and AD. Design Comparison study. Setting Memory Clinic of the Salpetriere Hospital, Paris, France. Patients Twenty-six patients with FTD and 64 patients with AD. Main Outcome Measures Comparison of FAB and Mini-Mental State Examination (MMSE) scores between patients with FTD and those with AD. Results The mean ± SD FAB scores significantly differed between patients with FTD (7.6 ± 4.2) and those with AD (12.6 ± 3.7) ( P Conclusions The FAB takes less than 10 minutes to administer and provides an objective measure to distinguish FTD from AD in mildly demented patients.
-
the fab a Frontal assessment battery at bedside
Neurology, 2000Co-Authors: Bruno Dubois, Andrea Slachevsky, Irene Litvan, B PillonAbstract:Objective: To devise a short bedside cognitive and behavioral battery to assess Frontal Lobe functions. Methods: The designed battery consists of six subtests exploring the following: conceptualization, mental flexibility, motor programming, sensitivity to interference, inhibitory control, and environmental autonomy. It takes approximately 10 minutes to administer. The authors studied 42 normal subjects and 121 patients with various degrees of Frontal Lobe Dysfunction (PD, n = 24; multiple system atrophy, n = 6; corticobasal degeneration, n = 21; progressive supranuclear palsy, n = 47; frontotemporal dementia, n = 23). Results: The Frontal Assessment Battery scores correlated with the Mattis Dementia Rating Scale scores (rho = 0.82, p p p p Conclusion: The Frontal Assessment Battery is easy to administer at bedside and is sensitive to Frontal Lobe Dysfunction.
-
relation of anosognosia to Frontal Lobe Dysfunction in alzheimer s disease
Journal of Neurology Neurosurgery and Psychiatry, 1994Co-Authors: A Michon, B Pillon, Bernard Deweer, Y Agid, Bruno DuboisAbstract:A self-rating scale of memory functions was administered to 24 non-depressed patients with probable Alzheimer's disease, divided into two groups according to the overall severity of dementia (mild, mini-mental state (MMS) > 21; moderate, MMS between 10 and 20). These groups did not significantly differ in their self-rating of memory functions. The same questionnaire was submitted to a member of each patient's family, who had to rate the patient's memory. An "anosognosia score" was defined as the difference between patient's and family's ratings. This score was highly variable, and covered, in the two groups, the full range between complete awareness of deficits and total anosognosia. Correlations between the anosognosia score and several neuropsychological data were searched for. No significant correlation was found with either the Wechsler memory scale, the MMS, or linguistic abilities and gestures. In contrast, this score was highly correlated with the "Frontal score", defined as the sum of scores on the Wisconsin card sorting test (WCST), verbal fluency, Luria's graphic series, and "Frontal behaviours" (prehension, utilisation, imitation behaviours, inertia, indifference). Among these tests of executive functions, the highest correlation with the anosognosia score was obtained on the WCST. This suggests that anosognosia in Alzheimer's disease is not related to the degree of cognitive deterioration but results, at least in part, from Frontal Dysfunction.
