Brain activation during the fist-edge-palm test: a functional MRI study

Luria's fist-edge-palm test: A small change makes a big difference

Slight modifications in the instructions or administration of neuropsychological tests could result in noticeable differences in performance. A good example is offered by a test devised by Luria to assess executive functioning in motor planning, the three-step fist-edge-palm (FEP) test, which is still frequently employed in clinical settings and features in several neuropsychological test batteries such as the Frontal Assessment Battery (FAB). While Luria described the orientation of the fist as horizontal to the testing desk (hFEP), recent versions of the task indicate the fist should be vertical to the testing desk (vFEP). The current study examined whether administering the hFEP or the vFEP tests results in different performance in healthy people, and whether one version is better than the other at detecting impairments in a patient population. The hFEP proved more challenging for healthy adults than the vFEP, and people with brain damage committed more errors on the hFEP than the vFEP. Both versions correlated with executive measures but also with several other cognitive variables, indicating that the test is not a specific marker of executive functions. Although performance on the FEP is sensitive to articulatory suppression, faster pace, and the number of sequences performed, none of these conditions fully account for the differences between the hFEP and vFEP. The additional demand of the hFEP appears to be due to the less natural (i.e., automatic) orientation of the horizontal fist. In conclusion, a small change in the administration of the test, eluding Luria's instructions, grossly modified its sensitivity. Clinicians and researchers should be wary of modifying instructions or testing procedures without considering the possible consequences of such modifications.

Cognitive Processes and Resting-State Functional Neuroimaging Findings in High Schizotypal Individuals and Schizotypal Personality Disorder Patients: A Systematic Review

Ample research findings indicate that there is altered brain functioning in the schizophrenia spectrum. Nevertheless, functional neuroimaging findings remain ambiguous for healthy individuals expressing high schizotypal traits and patients with schizotypal personality disorder (SPD). The purpose of this systematic review was to identify patterns of task-related and resting-state neural abnormalities across these conditions. MEDLINE-PubMed and PsycINFO were systematically searched and forty-eight studies were selected. Forty studies assessed healthy individuals with high schizotypal traits and eight studies examined SPD patients with functional neuroimaging techniques (fNIRS; fMRI; Resting-state fMRI). Functional alterations in striatal, frontal and temporal regions were found in healthy individuals with high schizotypal traits. Schizotypal personality disorder was associated with default mode network abnormalities but further research is required in order to better conceive its neural correlates. There was also evidence for functional compensatory mechanisms associated with both conditions. To conclude, the findings suggest that brain dysfunctions are evident in individuals who lie along the subclinical part of the spectrum, further supporting the continuum model for schizophrenia susceptibility. Additional research is required in order to delineate the counterbalancing processes implicated in the schizophrenia spectrum, as this approach will provide promising insights for both conversion and protection from conversion into schizophrenia.

Fist-Edge-Palm (FEP) test has a high sensitivity in differentiating dementia from normal cognition in Parkinson's disease

BACKGROUND

The Fist-Edge-Palm (FEP) test takes 0.5-3 min to complete and is highly sensitive in differentiating Alzheimer's disease and frontotemporal dementia from normal cognition, but it has not yet been studied in Parkinson's disease (PD).

OBJECTIVE

To determine the sensitivity and specificity of the FEP test in screening patients with PD for cognitive impairment and dementia.

METHODS

PD patients were recruited and divided into three groups based on cognitive status: normal cognition, mild cognitive impairment (MCI) and dementia according to 2015 MDS clinical diagnostic criteria for PD and clinical dementia rating scale (CDR) assessment for cognitive status. MMSE, FEP and clock drawing test (CDT) were tested in all recruited PD patients. Chi-square test was used to compare the sensitivity of FEP and CDT in detecting PDD and PD-MCI.

RESULTS

A total of 108 PD patients were included: 52 normal cognition, 28 MCI, and 28 dementia. The sensitivity of FEP in differentiating PDD from PD-NC was 96.4% and the sensitivity for PD-MCI from PD-NC was 71.4%. The sensitivity of CDT in differentiating PDD from PD-NC was 71.4% and PD-MCI from PD-NC was 53.6%. The sensitivities of FEP and CDT were 83.9% and 62.5%, respectively, in identifying cognitive impairment (CDR ≥ 0.5) in PD patients.

CONCLUSION

FEP is a sensitive screening tool in differentiating PDD or PD-MCI from PD-NC, and it is much faster than MMSE and more sensitive than CDT. FEP may be a practical screening tool for daily clinical practice.

Examination of the Prefrontal Cortex Hemodynamic Responses to the Fist-Edge-Palm Task in Naïve Subjects Using Functional Near-Infrared Spectroscopy

The Fist-Edge-Palm (FEP) task, a manual hand task, has been used to detect frontal dysfunctions in clinical situations: its performance failures are observed in various prefrontal cortex (PFC)-related disorders, including schizophrenia. However, previous imaging studies reported that the performance of the FEP task activated motor-related areas, but not the PFC. Here, we aimed to investigate the relationships between the performance of the FEP task and PFC functions. Hemodynamic activity in the PFC, including the dorsolateral PFC (area 46) and frontal pole (area 10), was recorded. Healthy young subjects performed the FEP task as well as a palm tapping (PT) task (control task) three times. The subjects also completed a Wisconsin Card Sorting Test (WCST) and Schizotypal Personality Scale (STA) questionnaire. We found that hemodynamic activity (Oxy-Hb) in the PFC increased in the first trial of the FEP task but decreased considerably in the second and third trials compared to the PT task. The number of performance errors in the FEP task also decreased in the second and third trials. Error reduction (i.e., learning) in the FEP task between the first and second trials was negatively correlated with schizotypal trait and the number of perseveration errors in the WCST. Furthermore, changes in the PFC hemodynamic activity between the first and second trials were positively correlated with error reduction in the FEP task between the first and second trials, and negatively correlated with the number of perseveration errors in the WCST. These results suggest that learning in the FEP task requires PFC activation, which is negatively associated with perseveration errors in the WCST. The results further suggest that the FEP task, in conjunction with near-infrared spectroscopy, may be useful as a diagnostic method for various disorders with PFC dysfunction.

Prospective investigation of cerebellar cognitive affective syndrome in a previously non-demented population of acute cerebellar stroke

OBJECTIVE

In this prospective study, we aimed to investigate the presence and evolution of cerebellar cognitive affective syndrome in a cohort of isolated cerebellar stroke with no known cognitive or psychiatric impairment. We tried to distinguish the unconfounded effect of cerebellar lesions on neuropsychological processing.

METHODS

After a meticulous exclusion procedure based on possible confounders, we recruited 14 patients and 13 age-matched healthy controls to the study, prospectively. All of the patients had a detailed initial neuropsychological assessment at the first week and a follow-up assessment at the 4th month after stroke.

RESULTS

The prevalence of cognitive or behavioral-affective abnormalities in our cohort were 86% and 64% respectively. The patients exhibited mild and transient affective-behavioral abnormalities except for depressive symptoms that persisted in the subacute stage. They scored lower in general cognitive performance as revealed by mini mental test (p=0.001). Memory, executive functions, attention and working memory, central processing speed, and linguistic abilities were impaired (p<0.001; p=0.001; p=0.007; p=0.05; p<0.001 respectively). Improvement was evident only in memory domain of the cognitive functions in the subacute stage. Cognitive impairment was more likely with a medial or posterolateral infarct (p=0.014). Behavioral-affective abnormalities were not associated with a specific location in our cohort. Age seemed to negatively correlate with the recovery in general cognitive performance on the follow-up.

CONCLUSIONS

These findings show that acute denervation of cerebellocortical projections leads to mild affective-behavioral abnormalities, and full-blown cerebellar cognitive affective syndrome is rare. However, cognition was significantly affected after an acute cerebellar infarct even in a previously healthy, non-demented pure population.

What type of inhibition underpins performance on Luria's Fist-Edge-Palm task?

OBJECTIVE

The Fist-Edge-Palm task is a motor sequencing task believed to be sensitive to frontal lobe impairment. The present study aimed to investigate the inhibitory processes underlying successful execution of this task.

METHOD

Seventy-two healthy participants were asked to perform the Fist-Edge-Palm task paced at 120 bpms, 60 bpms and self-paced. They also completed assessments sensitive to recently dissociated forms of inhibition (the Hayling Sentence Completion Test and the Stroop Color-Word Test) that have recently been shown to be differentially lateralized (the right and left Prefrontal Cortex, respectively), and Cattell's Culture Fair Intelligence test.

RESULTS

Analysis revealed that performance on the Hayling Sentence Completion Test predicted the amount of crude errors and the overall score on the Fist-Edge-Palm task, and that pacing condition had no effect on this outcome. Neither the Stroop Color-Word Test nor Cattell's Culture Fair Intelligence Test predicted performance on the Fist-Edge-Palm task.

CONCLUSIONS

Consistent with some previous neuroimaging findings, the present findings suggest that Fist-Edge-Palm task performance relies on right lateralized inhibitory processes.

Neurological soft signs (NSS) and brain morphology in patients with chronic schizophrenia and healthy controls

Subtle abnormalities in sensory integration, motor coordination and sequencing of complex motor acts or neurological soft signs (NSS) are characteristic phenomena in patients with schizophrenia at any stage of the illness. Previous MRI studies in schizophrenia found NSS to be associated with cortical, thalamic and cerebellar changes. Since these studies mainly focused on first-episode or recent onset schizophrenia, the cerebral correlates of NSS in chronic schizophrenia remained rather unclear. 49 middle-aged patients with chronic schizophrenia with a mean duration of illness of 20.3 ± 14.0 years and 29 healthy subjects matched for age and sex were included. NSS were examined on the Heidelberg Scale and correlated to grey matter (GM) by using whole brain high resolution magnetic resonance imaging (3 Tesla) with SPM12/CAT12 analyses. As expected, NSS in patients were significantly (p≤0.001) elevated in contrast to healthy controls, a finding, which not only applied to NSS total score, but also to the respective subscales "motor coordination", "sensory integration", "complex motor tasks", "right/left and spatial orientation" and "hard signs". Within the patient group NSS total scores were significantly correlated to reduced GM in right lingual gyrus, left parahippocampal gyrus, left superior temporal gyrus, left thalamus (medial dorsal nucleus) and left posterior lobe of the cerebellum (declive). Respective negative associations could also be revealed for the subscales "motor coordination", "complex motor tasks" and "right/left and spatial orientation". These findings remained significant after FWE-correction for multiple comparisons and were confirmed when years of education, chlorpromazine-equivalents or variables indicating the severity of psychopathology were introduced as additional covariates. According to our results lingual, parahippocampal, superior temporal, inferior and middle frontal gyri, thalamus and cerebellum have to be considered as important sites of NSS in chronic schizophrenia. That these findings only applied for patients but not healthy controls may indicate a different pathogenesis of NSS.

Neural mechanism and heritability of complex motor sequence and audiovisual integration: A healthy twin study

Complex motor sequencing and sensory integration are two key items in scales assessing neurological soft signs. However, the underlying neural mechanism and heritability of these two functions is not known. Using a healthy twin design, we adopted two functional brain imaging tasks focusing on fist-edge-palm (FEP) complex motor sequence and audiovisual integration (AVI). Fifty-six monozygotic twins and 56 dizygotic twins were recruited in this study. The pre- and postcentral, temporal and parietal gyri, the supplementary motor area, and the cerebellum were activated during the FEP motor sequence, whereas the precentral, temporal, and fusiform gyri, the thalamus, and the caudate were activated during AVI. Activation in the supplementary motor area during FEP motor sequence and activation in the precentral gyrus and the thalamic nuclei during AVI exhibited significant heritability estimates, ranging from 0.5 to 0.62. These results suggest that activation in cortical motor areas, the thalamus and the cerebellum associated with complex motor sequencing and audiovisual integration function may be heritable.

Dysfunctional putamen modulation during bimanual finger-to-thumb movement in patients with Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder affecting middle-aged and elderly people. PD can be viewed as “circuit disorder,” indicating that large scale cortico-subcortical pathways were involved in its pathophysiology. The brain network in an experimental context is emerging as an important biomarker in disease diagnosis and prognosis prediction. This context-dependent network for PD and the underling functional mechanism remains unclear. In this paper, the brain network profiles in 11 PD patients without dementia were studied and compared with 12 healthy controls. The functional magnetic resonance imaging (fMRI) data were acquired when the subjects were performing a pseudorandomized unimanual or bimanual finger-to-thumb movement task. The activation was detected and the network profiles were analyzed by psychophysiological interaction (PPI) toolbox. For the controls and PD patients, the motor areas including the primary motor and premotor areas, supplementary motor area, the cerebellum and parts of the frontal, temporal and parietal gyrus were activated. The right putamen exhibited significant control > PD activation and weaker activity during the bimanual movement relative to the unimanual movement in the control group. The decreased putamen modulation on some nucleus in basal ganglia, such as putamen, thalamus and caudate, and some cortical areas, such as cingulate, parietal, angular, frontal, temporal and occipital gyrus was detected in the bimanual movement condition relative to the unimanual movement condition. Between-group PPI difference was detected in cingulate gyrus, angular gyrus and precuneus (control > PD) and inferior frontal gyrus (PD > control). The deficient putamen activation and its enhanced connectivity with the frontal gyrus could be a correlate of impaired basal ganglia inhibition and frontal gyrus compensation to maintain the task performance during the motor programs of PD patients.

Prefrontal cortex connectivity dysfunction in performing the Fist-Edge-Palm task in patients with first-episode schizophrenia and non-psychotic first-degree relatives

Neurological soft signs have been considered one of the promising neurological endophenotypes for schizophrenia. However, most previous studies have employed clinical rating data only. The present study aimed to examine the neurobiological basis of one of the typical motor coordination signs, the Fist–Edge–Palm (FEP) task, in patients with first-episode schizophrenia and their non-psychotic first degree relatives. Thirteen patients with first-episode schizophrenia, 14 non-psychotic first-degree relatives and 14 healthy controls were recruited. All of them were instructed to perform the FEP task in a 3 T GE Machine. Psychophysiological interaction (PPI) analysis was used to evaluate the functional connectivity between the sensorimotor cortex and frontal regions when participants performed the FEP task compared to simple motor tasks. In the contrast of palm-tapping (PT) vs. rest, activation of the left frontal–parietal region was lowest in the schizophrenia group, intermediate in the relative group and highest in the healthy control group. In the contrast of FEP vs. PT, patients with schizophrenia did not show areas of significant activation, while relatives and healthy controls showed significant activation of the left middle frontal gyrus. Moreover, with the increase in task complexity, significant functional connectivity was observed between the sensorimotor cortex and the right frontal gyrus in healthy controls but not in patients with first episode schizophrenia. These findings suggest that activity of the left frontal–parietal and frontal regions may be neurofunctional correlates of neurological soft signs, which in turn may be a potential endophenotype of schizophrenia. Moreover, the right frontal gyrus may play a specific role in the execution of the FEP task in schizophrenia spectrum disorders.

•

Examine the neurobiological basis of the typical Fist–Edge–Palm (FEP) signs

•

Patients with first-episode schizophrenia showed functional connectivity of the FEP signs.

•

Right frontal gyrus plays a specific role in the FEP in patients and non-psychotic first-degree relatives.

Luria revisited: cognitive research in schizophrenia, past implications and future challenges

Contemporary psychiatry is becoming more biologically oriented in the attempt to elicit a biological rationale of mental diseases. Although mental disorders comprise mostly functional abnormalities, there is a substantial overlap between neurology and psychiatry in addressing cognitive disturbances. In schizophrenia, the presence of cognitive impairment prior to the onset of psychosis and early after its manifestation suggests that some neurocognitive abnormalities precede the onset of psychosis and may represent a trait marker. These cognitive alterations may arise from functional disconnectivity, as no significant brain damage has been found. In this review we aim to revise A.R. Luria's systematic approach used in the neuropsychological evaluation of cognitive functions, which was primarily applied in patients with neurological disorders and in the cognitive evaluation in schizophrenia and other related disorders. As proposed by Luria, cognitive processes, associated with higher cortical functions, may represent functional systems that are not localized in narrow, circumscribed areas of the brain, but occur among groups of concertedly working brain structures, each of which makes its own particular contribution to the organization of the functional system. Current developments in neuroscience provide evidence of functional connectivity in the brain. Therefore, Luria's approach may serve as a frame of reference for the analysis and interpretation of cognitive functions in general and their abnormalities in schizophrenia in particular. Having said that, modern technology, as well as experimental evidence, may help us to understand the brain better and lead us towards creating a new classification of cognitive functions. In schizophrenia research, multidisciplinary approaches must be utilized to address specific cognitive alterations. The relationships among the components of cognitive functions derived from the functional connectivity of the brain may provide an insight into cognitive machinery.

Luria revisited: complex motor phenomena in first episode schizophrenia and schizophrenia spectrum disorders

Patients with schizophrenia frequently exhibit motor deficits. However, to date, there are no studies comparing motor performance in first episode patients with schizophrenia and schizophrenia spectrum disorders (SSD; e.g. schizoaffective and brief psychosis). Participants comprised 57 first episode patients with schizophrenia, 32 first episode patients with SSD, and 51 healthy controls who underwent neuropsychological testing based on Luria׳s systematic approach, including the following tests on complex motor sequencing: the Fist-Edge-Palm (FEP) test and the bimanual probe (BP). Schizophrenia patients performed worse than SSD patients in FEP and BP, and both patient groups showed decreased scores compared to healthy controls. Furthermore, we found that a higher proportion of schizophrenia cases failed to correct their motor performance and needed external error correction, while SSD cases exhibited a higher proportion of self-correction in FEP and in BP. Lack of insight and poor executive functioning correlated with motor performance in schizophrenia, while impulse control and difficulties in abstract thinking were related to motor performance in schizophrenia spectrum disorder. Thus, psychomotor impairments appear already in first episode patients with schizophrenia and differ from impairments in SSD. Especially the inability to self-correct errors may be characteristic of schizophrenia, suggesting that impairments in error monitoring are related to psychomotor dysfunction in schizophrenia.

Sequential motor task (Luria's Fist-Edge-Palm Test) in children with benign focal epilepsy of childhood with centrotemporal spikes

This study evaluated the sequential motor manual actions in children with benign focal epilepsy of childhood with centrotemporal spikes (BECTS) and compares the results with matched control group, through the application of Luria's fist-edge-palm test. The children with BECTS underwent interictal single photon emission computed tomography (SPECT) and School Performance Test (SPT). Significant difference occurred between the study and control groups for manual motor action through three equal and three different movements. Children with lower school performance had higher error rate in the imitation of hand gestures. Another factor significantly associated with the failure was the abnormality in SPECT. Children with BECTS showed abnormalities in the test that evaluated manual motor programming/planning. This study may suggest that the functional changes related to epileptiform activity in rolandic region interfere with the executive function in children with BECTS.

The frontal assessment battery in the differential diagnosis of dementia

AIM

The Frontal Assessment Battery (FAB) has been used in different clinical settings as a valuable quick bedside test for executive dysfunction. The aim of the study was to evaluate clinical utility of the FAB for differential diagnosis of Alzheimer disease (AD), subcortical vascular cognitive impairment (scVCI), and frontotemporal lobar degeneration (FTLD).

METHODS

Scores of the total FAB test and subtests were compared between consecutive series of 37 patients with AD, 31 patients with scVCI, 13 patients with FTLD, and 29 cognitively healthy individuals.

RESULTS

There was no statistically significant difference in the total FAB scores among the groups of patients with dementia. When comparing subtest scores, patients with FTLD had significantly lower scores on the lexical fluency subtest compared to the patients with AD (P<.001) or scVCI (P<.001); patients with scVCI had significantly lower scores on the motor series subtest compared to patients with FTLD (P=.02) and AD (P=.035) and on conflicting instructions subtest compared to patients with AD (P=.033).

CONCLUSION

Some FAB subtests might enhance diagnostic accuracy taking into account clinical history and other tests of executive function.

Dementia incidence and mortality in middle-income countries, and associations with indicators of cognitive reserve: a 10/66 Dementia Research Group population-based cohort study

BACKGROUND

Results of the few cohort studies from countries with low incomes or middle incomes suggest a lower incidence of dementia than in high-income countries. We assessed incidence of dementia according to criteria from the 10/66 Dementia Research Group and Diagnostic and Statistical Manual of Mental Disorders (DSM) IV, the effect of dementia at baseline on mortality, and the independent effects of age, sex, socioeconomic position, and indicators of cognitive reserve.

METHODS

We did a population-based cohort study of all people aged 65 years and older living in urban sites in Cuba, the Dominican Republic, and Venezuela, and rural and urban sites in Peru, Mexico, and China, with ascertainment of incident 10/66 and DSM-IV dementia 3-5 years after cohort inception. We used questionnaires to obtain information about age in years, sex, educational level, literacy, occupational attainment, and number of household assets. We obtained information about mortality from all sites. For participants who had died, we interviewed a friend or relative to ascertain the likelihood that they had dementia before death.

FINDINGS

12,887 participants were interviewed at baseline. 11,718 were free of dementia, of whom 8137 (69%) were reinterviewed, contributing 34,718 person-years of follow-up. Incidence for 10/66 dementia varied between 18·2 and 30·4 per 1000 person-years, and were 1·4-2·7 times higher than were those for DSM-IV dementia (9·9-15·7 per 1000 person-years). Mortality hazards were 1·56-5·69 times higher in individuals with dementia at baseline than in those who were dementia-free. Informant reports suggested a high incidence of dementia before death; overall incidence might be 4-19% higher if these data were included. 10/66 dementia incidence was independently associated with increased age (HR 1·67; 95% CI 1·56-1·79), female sex (0·72; 0·61-0·84), and low education (0·89; 0·81-0·97), but not with occupational attainment (1·04; 0·95-1·13).

INTERPRETATION

Our results provide supportive evidence for the cognitive reserve hypothesis, showing that in middle-income countries as in high-income countries, education, literacy, verbal fluency, and motor sequencing confer substantial protection against the onset of dementia.

FUNDING

Wellcome Trust Health Consequences of Population Change Programme, WHO, US Alzheimer's Association, FONACIT/ CDCH/ UCV.

Neuropsychological profiles and short-term outcome in late-onset depression

OBJECTIVE

Neuropsychological impairments are common in older persons with late-onset depression. This study examined the relationship between neuropsychological profiles and short-term outcome in late-onset depression.

METHODS

A total of 54 non-demented Chinese elders presented with their first major depressive episode after 60 years of age participated in this study and were treated according to a standardised protocol. At entry, they were assessed on neurological signs (Parkinsonian features and neurological soft signs) and neuropsychological measures (executive function, psychomotor-speed, attention and working memory, episodic memory, conceptualisation, construction and global cognitive function). The Hamilton Depression Rating Scale (HAM-D) was administered at baseline, the sixth and 12th week of treatment.

RESULTS

Abnormal fist-edge-palm (FEP) test, a sign reflecting impairment in motor sequencing, was more common in non-remitters (defined as HAM-D score above 7) at the 12th week of treatment.

CONCLUSIONS

The FEP test may be included in the clinical assessment for patients with late-onset depression to identify a susceptible group who may require more intensive treatment. Further research is warranted to ascertain the link between late-onset depression, neuropsychological deficits and prognosis.

Neuroanatomical correlates of neurological soft signs in antipsychotic-naive schizophrenia

Recent imaging studies suggest that the so-called "soft" neurological signs in schizophrenia might have neuroanatomical validity. We examined gray matter volume correlates of neurological soft signs (NSS) in antipsychotic-naive schizophrenia patients using an automated image analysis technique. NSS were assessed using a modified neurological evaluation scale with good inter-rater reliability. Magnetic resonance images of 30 schizophrenia patients and 27 age-, sex-, education- and handedness-matched healthy controls were processed using optimized voxel-based morphometry (VBM). Logistic regression analysis showed that only the Motor Sequencing Signs (MSS) sub-score was a significant predictor of subject's status among the NSS sub-scores. Optimized VBM analysis showed that the MSS sub-score had a significant negative correlation with total and regional gray matter volumes (prefrontal, posterior cingulate, temporal cortices, putamen, and cerebellum) in schizophrenia patients but not in controls. Prefrontal and temporal cortices, putamen and cerebellum had significant volume deficits in patients. Cortical and cerebellar correlates of the sub-score MSS support the concept of "cognitive dysmetria" in schizophrenia.

Dexterous movement complexity and cerebellar activation: a meta-analysis

The importance of the cerebellum in coordinates of movement has been established by lesion studies. However, there is no clear understanding of whether there is consistent activation in cerebellum across various motor task complexities or how different parts of the cerebellum contribute to finger coordinates in dexterous manipulation. This article reviews imaging studies with data from healthy subjects. A mini meta-analysis using label-based and activation likelihood estimation (ALE) methods reveals that ipsilateral anterior and vermis regions of the cerebellum were consistently activated across various dexterous movement complexities and were associated with finger and hand movement.

A regulation role of the prefrontal cortex in the fist-edge-palm task: evidence from functional connectivity analysis

The Fist-Edge-Palm (FEP) task is a motor sequencing task that is widely used in neurological examination. Deficits in this task are believed to reflect impairment in the frontal lobe regions. However, two recent functional brain imaging studies of the FEP task using conventional subtraction analysis failed to demonstrate FEP-induced activation in the prefrontal cortex (PFC), which contradicts existing neuropsychological literature. In this study, psychophysiological interaction (PPI) analysis was used to reanalyze our previous neuroimaging dataset from 10 healthy subjects in order to evaluate the changes of functional connectivity between the sensorimotor cortex and the prefrontal regions during the performances of the FEP task relative to simple motor control tasks. The PPI analysis revealed significantly increased functional connectivity between bilateral sensorimotor cortex and the right inferior and middle frontal cortex during the performance of the FEP task compared with the control tasks. However, regional signal changes showed no significant activation differences in these prefrontal regions. These results provide evidence supporting the involvement of the frontal lobe in the performance of the FEP task, and suggest a role of regulation, rather than direct participation, of the prefrontal cortex in the execution of complex motor sequence tasks such as the FEP task.

Behavioural assessment of the dysexecutive syndrome (BADS) in healthy elders and Alzheimer's disease patients: preliminary study

Although the main initial deficit is considered to be in the memory domain, an early impairment of executive functions is also found in AD where these deficits are correlated to functional impairment. Ecological tests are more indicated to evaluate executive impairment, and are better able to assist in treating AD patients than more commonly used tests.

The neural basis of motor sequencing: an fMRI study of healthy subjects

The present study used functional MRI to clarify the brain regions activated during a series of motor sequencing tasks in healthy volunteers. Ten subjects were scanned while performing three soft signs tasks ranging from simple (PT: palm tapping), moderate (PS: pronation/supination) to complex movements (FEP: fist-edge-palm). The FEP task induced significant activations within the cortical networks including bilateral sensorimotor, SMA, left parietal, and right cerebellum, but no activation in the prefrontal area. Moreover, the percentage signal changes within the left sensorimotor, left thalamus and right cerebellum showed an increase in activation with task complexity. The present findings challenge the traditional belief that FEP was a task for frontal lobe function but suggest that successful performance of more complex neurological soft sign tasks like FEP requires the participation of more brain areas than simple motor sequencing and coordination task like PS and PT. These also provide the empirical data on the neural basis of neurological soft signs for further study in other clinical group like schizophrenia in the near future.

Performance in Luria's Fist-Edge-Palm Test According to Educational Level

OBJECTIVE

To investigate the performance of a large population with heterogeneous educational background in a test apparently uninfluenced by formal education.

METHODS

We administered the Luria's fist-edge-palm test to 966 elderly individuals (299 illiterates) while screening for dementia in a Brazilian population. Individuals with scores in the Mini-Mental State Examination below the 25th percentile (adjusted for each of 4 educational levels) were considered suspect for dementia and excluded. The influence of educational level, age, and gender on the occurrence of failures and on the number of demonstrations for a successful reproduction was investigated.

RESULTS

The final population comprised 745 individuals (238 illiterates). Forty-eight individuals (25 illiterates) were unable to reproduce the sequence. Logistic regression showed that illiteracy was associated with failure, whereas gender and age were not. The proportion of individuals failing to reproduce the sequence was inversely related to the years of schooling. For those individuals who were able to reproduce the sequence, the number of demonstrations for successful reproduction was also inversely related to the years of schooling.

CONCLUSION

Illiteracy and low educational level are associated with impaired performance in the fist-edge-palm test, which may be the result of the use of different strategies according to educational level.

Involvement of the inferior frontal junction in cognitive control: meta-analyses of switching and Stroop studies

There is growing evidence that a specific region in the posterior frontolateral cortex is involved intimately in cognitive control processes. This region, located in the vicinity of the junction of the inferior frontal sulcus and the inferior precentral sulcus, was termed the inferior frontal junction (IFJ). The IFJ was shown to be involved in the updating of task representations and to be activated commonly in a within-subject investigation of a task-switching paradigm, the Stroop task, and a verbal n-back task. Here, we investigate the involvement of the IFJ in cognitive control by employing a meta-analytic approach. Two quantitative meta-analyses of functional magnetic resonance imaging (fMRI) studies were conducted. One meta-analysis included frontal activations from task-switching, set-shifting, and stimulus-response (S-R) reversal studies, the other included frontal activations from color-word Stroop studies. Results showed highly significant clustering of activations in the IFJ in both analyses. These results provide strong evidence for the consistent involvement of the IFJ in both switching and Stroop paradigms. Furthermore, they support our concept of areal specialization in the frontolateral cortex, which posits that it is not only the middorsolateral part that plays an important role in cognitive control, but also the IFJ. Finally, our results demonstrate how quantitative meta-analyses can be used to test hypotheses about the involvement of specific brain regions in cognitive control.

A fMRI Study of Age-Related Differential Cortical Patterns During Cued Motor Movement

Healthy adults of three age groups (young, middle-age and older) were cued by a multimedia projector to perform a series of simple (making a fist, opening/closing of the mouth) and complex (opposition of index finger and thumb, chewing gum) motor tasks while being scanned by functional magnetic resonance imaging. Our results showed that in unilateral hand movements, the premotor/motor cortex in the contralateral hemisphere was most strongly activated. Supplementary motor cortex involvement was usually present in the young and not in the old, except in precision movement when supplementary motor cortex was also involved in the old. For movements of the face (chewing, opening and closing of mouth), the prefrontal cortex was activated in the old age group but finger and hand movements never activated the prefrontal cortex in any age. Furthermore, areas like insula and cingulate gyrus might be activated in motor tasks. We conclude that different motor activities triggered diverse activation patterns which differed in different age groups.

Unified SPM–ICA for fMRI analysis

A widely used tool for functional magnetic resonance imaging (fMRI) data analysis, statistical parametric mapping (SPM), is based on the general linear model (GLM). SPM therefore requires a priori knowledge or specific assumptions about the time courses contributing to signal changes. In contradistinction, independent component analysis (ICA) is a data-driven method based on the assumption that the causes of responses are statistically independent. Here we describe a unified method, which combines ICA, temporal ICA (tICA), and SPM for analyzing fMRI data. tICA was applied to fMRI datasets to disclose independent components, whose number was determined by the Bayesian information criterion (BIC). The resulting components were used to construct the design matrix of a GLM. Parameters were estimated and regionally-specific statistical inferences were made about activations in the usual way. The sensitivity and specificity were evaluated using Monte Carlo simulations. The receiver operating characteristic (ROC) curves indicated that the unified SPM-ICA method had a better performance. Moreover, SPM-ICA was applied to fMRI datasets from twelve normal subjects performing left and right hand movements. The areas identified corresponded to motor (premotor, sensorimotor areas and SMA) areas and were consistently task related. Part of the frontal lobe, parietal cortex, and cingulate gyrus also showed transiently task-related responses. The unified method requires less supervision than the conventional SPM and enables classical inference about the expression of independent components. Our results also suggest that the method has a higher sensitivity than SPM analyses.