Frontal Lobe Cognitive Function Research Articles

Photobiomodulation improves frontal lobe cognitive functions and mental health of older adults with non-amnestic mild cognitive impairment: Case studies.

This study investigated the effects of transcranial photobiomodulation (tPBM) on improving the frontal lobe cognitive functions and mental health of older adults. Three older adults with mild cognitive impairment (MCI) of the non-amnestic type received 18-session tPBM stimulation for 9 weeks and were assessed with neuropsychological tests of memory and executive functions and standardized questionnaires on depressive and anxiety symptoms, global cognitive functions, and daily functioning abilities before and after tPBM stimulation. At baseline, their intrusion and/or perseveration errors in a verbal memory test and a fluency test, as measures of the frontal lobe cognitive functions, were in the borderline to severely impaired range at baseline. After tPBM stimulation, the three older adults showed various levels of improvement in their frontal lobe cognitive functions. One older adult's intrusion and perseveration errors improved from the <1st-2nd percentile (moderately to severely impaired range) to the 41st-69th percentile (average range), another older adult's intrusion errors improved from the 11th percentile to the 83rd percentile, and the third older adult's intrusion errors improved from the 5th percentile to the 56th percentile. Moreover, improvements in their anxiety and/or depressive symptoms were also observed. One older adult's depressive and anxiety symptoms improved from the severe range at baseline to the mild range after the intervention. The other two older adults' depressive symptoms improved from the mild range at baseline to the normal range after the intervention. These findings provide preliminary support for the potential of tPBM to improve the frontal lobe cognitive functions and mental health of older adults with MCI. Given the small sample size of only three older adults and the absence of a placebo control group, larger randomized controlled studies are needed to confirm its potential.

Effect of surgical menopause and frontal lobe cognitive function

Objective This study aims to explore the prevalence of decreased frontal lobe function and its associated factors in women with surgical menopause. Methods This study is a retrospective analysis of a cross-sectional study conducted between October 2013 and July 2014. Data from 164 women with surgical menopause were analyzed. The Montreal Cognitive Assessment Thai version (MoCA-T) test was administered by a psychologist. The MoCA frontal lobe function score was derived from visuospatial/executive, abstraction, attention, and verbal fluency tests. Multivariable logistic regression was used to assess data associated with decreased frontal lobe function. Results The mean age of participants was 56.3 ± 6.9 years, and the mean time since menopause was 11.3 ± 7.4 years. The prevalence of decreased frontal lobe function score was 73.8%, with an average score of 6.21 ± 1.84. The independent factor associated with a lower MoCA frontal lobe function score was duration of education greater than 6 years. Conclusion Our study adds information about decreased frontal lobe function in almost three-quarters of women with surgical menopause. Duration of education greater than 6 years was a protective factor. Menopause hormone therapy usage did not seem to increase the detrimental effect on frontal lobe function when initiated in young women with surgical menopause.

Do interictal EEG findings reflect cognitive function in juvenile myoclonic epilepsy?

PurposeThis study investigated the relationship between frontal lobe cognitive function and frontal focal electroencephalography (EEG) findings in patients with juvenile myoclonic epilepsy (JME). MethodsThe study enrolled 60 patients diagnosed with JME and followed at the Epilepsy Outpatient Clinic of the University of Health Sciences, Bakırkoy Psychiatric Hospital, and 30 healthy volunteers. Demographic and clinical features were recorded. Frontal lobe cognitive functions were tested in both groups. Video-EEG recordings of patients with JME were evaluated. The presence and duration of generalized discharges, the presence and lateralization of focal findings, and the presence of generalized discharges during hyperventilation and photic stimulation were recorded during EEG. Cognitive function test results were compared between the two groups, and the relationship between the EEG findings and cognitive function was investigated. ResultsThe study included 35 (58.3%) female and 25 (41.6%) male patients and 17 (56.7%) female and 13 (43.3%) male healthy controls. The mean ages of the group with JME and controls were 28.3 ± 8.6 (16–50) and 31.3 ± 7.9 (17–45) years, respectively. Patients with JME performed more poorly on the frontal lobe cognitive tests than controls (p < 0.05). Patients whose generalized discharges were longer than 1 s performed more poorly on tests evaluating attention and made more perseverative errors (p < 0.05). There was no significant correlation between the presence of focal EEG findings and the scores on frontal lobe cognitive functions tests in the group with JME (p > 0.05). ConclusionFrontal lobe cognitive functions are affected in patients with JME. The cognitive effects were more pronounced in patients with prolonged generalized discharges on EEG.

Pathological risk-propensity typifies Mafia members\u2019 cognitive profile

Since the recruitment process, Italian Mafias impose on their members a strict code of conduct. These rigid rules regulate their private and public behavior, implying a total adhesion to the group’s values. Such juridical and social aspects substantially distinguish organized crime (OC) from ordinary crime. It is still unknown whether these two categories of offenders also show distinctive cognitive traits. Here we investigated the frontal lobe cognitive functions of 50 OC prisoners from the Mafia and 50 non-OC prisoners based on the performance of 50 non-prisoner controls. We found that OC members were more likely to show pathological risk-propensity than non-OC prisoners. We interpret this finding as the result of the internal dynamics of Mafia groups. OC is a worldwide threat, and the identification of cognitive traits behind criminal behavior will help in devising focused prevention policies.

Influence of collateral circulation on cerebral blood flow and frontal lobe cognitive function in patients with severe internal carotid artery stenosis

BackgroundThis study aimed to investigate the cerebral blood flow (CBF) and frontal lobe cognitive function in severe internal carotid artery (ICA) stenosis patients with different types of collateral circulation.MethodsOne hundred twenty-six patients with severe unilateral ICA stenosis were enrolled. Digital subtraction angiography (DSA) was performed to recruit patients with one of three common types of collateral circulation: anterior communicating artery (AcoA), posterior communicating artery (PcoA) and ophthalmic artery (OA). The hemodynamic parameters of the middle cerebral artery (MCA) were measured using transcranial Doppler (TCD), and the individual frontal lobe cognitive attention functions were evaluated using Word Fluency Test, Trail-Making Test (TMT), Digit Span, and Stroop Color Word Test (SCWT). The correlation between hemodynamic changes and the scores of all tasks was analyzed.ResultsOn the side of arterial stenosis, the CBF velocities were highest in AcoA group and lowest in the OA group. All patients performed worse in TMT and Digit Span than the matched normal controls. The AcoA group exhibited a lower pulsatility index (PI) and a longer response time in the Stroop task, but had a higher accuracy rate in the Stroop task and higher scores in Word Fluency Test than the PcoA and OA groups. In all the three groups, PI was positively correlated with the accuracy rate for Stroop interference effects.ConclusionsOur findings suggested that the frontal lobe cognitive function of patients with ICA was impaired, and AcoA collaterals may be beneficial for selective attention functions, whereas OA collaterals may be associated with impairment of selective attention functions. Additionally, a high PI may be an indicator for identifying impaired selective attention in patients with severe ICA stenosis.

Frontal lobe cognitive functions and electroencephalographic features in juvenile myoclonic epilepsy

PurposeThe study aimed to examine the relationship between frontal lobe functions and interictal electroencephalography (EEG) discharge characteristics of patients with juvenile myoclonic epilepsy (JME). MethodThirty patients with JME who had EEG with asymmetrical generalized discharge (aEEG), 15 patients with JME who had EEG with symmetrical generalized discharge (sEEG), and 15 healthy controls were included in the study. To evaluate attention, the digit span and Corsi block tests were used; to evaluate memory, we applied verbal and visual memory tests; to evaluate frontal lobe functions, we used clock drawing, verbal fluency, the Stroop test, trail making, mental control, and antisaccadic eye movement tests as well as the continuous performance (CPT) tests. Ethical ConsiderationsThe research was approved by the Research Ethics Committee of the Bakirkoy Research and Training Hospital for Psychiatry, Neurology, Neurosurgery, with protocol number: 41340010/4891-262, date: 05.02.2013. ResultsThe mean age of the 45 patients with JME was 22.89 ± 6.77 years, and 34 (75.6%) were female. The age at onset of seizures and disease duration of the patients with JME was 15.56 ± 4.06 years (range, 9–26 years) and 7.20 ± 5.59 years (range, 1–25 years), respectively. All patients were under valproate (VPA) treatment, and the mean VPA dosage was 783.33 ± 379.14 mg/day. Patients with JME scored worse than the control group in attention, memory, and frontal lobe functions. In patients with aEEG, scores of attention, memory, and frontal lobe function tests were lower than in patients with sEEG; however, with the exception of CPT, they were not statistically significant. ConclusionCognitive functions in JME have been shown to be impaired. Furthermore, we concluded that the frontal lobe cognitive functions may be worse in patients with aEEG than in patients with sEEG. Further studies in patients with JME with aEEG abnormalities may lead to a better understanding of the pathophysiology of JME.

Raven coloured progressive matrices in migraine without aura patients.

Conflicting results emerged from studies investigating cognitive performances in migraine patients. Based on clinical and neuroradiological aspects, the possible involvement of executive functions has been especially taken into consideration. The aim of this study was to evaluate, in a population of subjects affected by migraine without aura (MwoA), frontal lobe cognitive functions. We enrolled all the consecutive patients affected by MwoA referred to our headache centre for a first evaluation. Each patient underwent a neuropsychological evaluation including Raven coloured progressive matrices (CPM). We collected variables as age, education, years of migraine, frequency of attacks and CPM scores. Relationship between continuous variables was explored with multiple regression lines, selecting the best-fitting trendline for each relationship. We obtained a final sample of 36 subjects (females: 62.5%; mean age: 42.25±10.21years). Patients had mean length of migraine history of 12.25±11.00years and a mean frequency of attacks of 8.06±7.15 per month. Linear regression underlines a progressive decrease of CPM score with the increase of the migraine history's length (R 2=0.8871; p<0.001), and the frequency of migraine attacks (R 2=0.3122; p<0.05). Our findings suggest that pathological CPM scores can be associated with the severity of migraine. These data seem to confirm the hypothesis of an impairment of executive functions in MwoA. Different hypotheses to explain cognitive impairment in migraine have been postulated including the impact of the typical white matter lesions and a long history of drug abuse. The possible relevant clinical consequence of a full comprehension of this particular aspect related to migraine deserves further attention and consideration.

Obese Adolescents Show Reduced Cognitive Processing Speed Compared with Healthy Weight Peers.

Childhood obesity and obesity-associated diabetes and metabolic syndrome (MetS) continue to rise. Obesity has been linked to structural and functional brain abnormalities, particularly in the frontal lobe. One hundred sixty-two adolescents (aged 19.53 ± 1.53 years) underwent medical, neurocognitive, and brain magnetic resonance imaging assessments. Participants were either healthy weight (BMI <25.0 kg/m2 or BMI percentile <85%) or obese (BMI ≥30.0 kg/m2 or BMI percentile ≥95%). We evaluated frontal lobe cognitive functions and the size of the corpus callosum (CC). Groups differed on four measures of processing speed contained in four different cognitive tests, but not on executive function. A confirmatory factor analysis verified that the significant processing speed variables loaded on the same factor. We also found differences between the weight groups on the area of the anterior portion of the CC, but not the overall CC. Only the Controlled Oral Word Association Test (COWAT) was significantly correlated with the area of the anterior portion of the CC. In the obese group, 32.4% met criteria for MetS. No differences were found between obese participants with or without MetS and none of the MetS factors contributed consistently to cognitive performance. Obese adolescents show slower cognitive processing speed while maintaining equivalent performance on executive functioning compared with their healthy weight peers. The group differences in the anterior portion of the CC, responsible for frontal lobe interhemispheric communication, may in part explain our processing speed findings. Future studies should include a longitudinal design and diffusion tensor imaging to examine the integrity of white matter.

Motor co-activation in siblings of patients with juvenile myoclonic epilepsy: an imaging endophenotype?

Juvenile myoclonic epilepsy is a heritable idiopathic generalized epilepsy syndrome, characterized by myoclonic jerks and frequently triggered by cognitive effort. Impairment of frontal lobe cognitive functions has been reported in patients with juvenile myoclonic epilepsy and their unaffected siblings. In a recent functional magnetic resonance imaging study we reported abnormal co-activation of the motor cortex and increased functional connectivity between the motor system and prefrontal cognitive networks during a working memory paradigm, providing an underlying mechanism for cognitively triggered jerks. In this study, we used the same task in 15 unaffected siblings (10 female; age range 18-65 years, median 40) of 11 of those patients with juvenile myoclonic epilepsy (six female; age range 22-54 years, median 35) and compared functional magnetic resonance imaging activations with 20 age- and gender-matched healthy control subjects (12 female; age range 23-46 years, median 30.5). Unaffected siblings showed abnormal primary motor cortex and supplementary motor area co-activation with increasing cognitive load, as well as increased task-related functional connectivity between motor and prefrontal cognitive networks, with a similar pattern to patients (P < 0.001 uncorrected; 20-voxel threshold extent). This finding in unaffected siblings suggests that altered motor system activation and functional connectivity is not medication- or seizure-related, but represents a potential underlying mechanism for impairment of frontal lobe functions in both patients and siblings, and so constitutes an endophenotype of juvenile myoclonic epilepsy.

Neuropsychological differentiation between Alzheimer's disease and dementia with Lewy bodies in a memory clinic

The aim of this study was to identify a useful neuropsychological instrument for making a differential clinical diagnosis between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). We examined 402 AD and 38 DLB patients with neuropsychological tests that covered general cognition, frontal lobe cognitive function, non-verbal abstract reasoning, working memory and attention, and verbal memory. Discriminant analysis using a stepwise method was performed to identify the measures best able to discriminate between AD and DLB. The AD patients performed significantly worse than the DLB patients on orientation to time, delayed recall subtests on the Mini-Mental State Examination, and logical memory subtests 1 and 2 of the Revised Wechsler Memory Scale. The DLB patients performed significantly worse than the AD patients on the attention, repetition, and pentagon copying subtests of the Mini-Mental State Examination, the constructional praxis subtests of the Alzheimer's Disease Assessment Scale-cognitive component-Japanese version, the Frontal Assessment Battery total score, Raven's Coloured Progressive Matrices (RCPM) sets A, AB, and B, and backward digit span. Discriminant analyses between AD and DLB established the key variables as Logical Memory 1, Logical Memory 2, backward digit span, RCPM, and delayed recall on the Mini-Mental State Examination. We inferred the AD-DLB discriminant index from the following discriminant analyses: AD-DLB discriminant index = (Backward digit span score + RCPM set B score) - (Logical Memory 1 score + Logical Memory 2 score), which offered a highly favourable value for diagnostic utility. The AD-DLB discriminant index, consisting of backward digit span, RCPM set B, and logical memory 1 and 2, is useful to differentiate between AD and DLB.

Cognitive Components of Frontal Lobe Function in Alcoholics Classified According to Lesch's Typology

This study examined the frontal lobe cognitive function and the mental state among patients with different types of alcohol dependence according to Lesch's typology. The frontal assessment battery (FAB) and the mini-mental status examination (MMSE) were given to 170 patients with alcoholism from a Brazilian outpatient service classified by Lesch's typology and to 40 non-alcoholic controls matched for age, gender, socio-demographic characteristics and education. Of the alcoholic sample, 21.2% were classified as Type I, 29.4% as Type II, 28.8% as Type III and 20.6% as Type IV. Alcoholics showed significantly lower overall scores on the MMSE and the FAB as compared to non-alcoholic subjects. Type IV alcoholics had lower MMSE and FAB overall scores as compared to non-alcoholic controls and also to all other types of alcoholic subjects. However, Type II and III subjects with alcoholism also had lower overall FAB scores, but not overall MMSE scores, as compared to non-alcoholic controls. The FAB subsets of motor programming, sensitivity to interference and inhibitory control were significantly reduced in Types II, III and IV alcoholics as compared to non-alcoholic subjects, but only motor programming remained impaired in Type IV alcoholics with preserved mental function. Executive dysfunctions in alcohol dependence seem to vary depending upon the type of alcoholism. Therefore, the determination of clinical type of alcohol dependence by applying Lesch's typology, along with brief mental state and frontal function examinations, is of clinical relevance in the examination of alcoholics and provides significant clues for more directed forms of alcohol dependence treatment.

Effects of an Exercise Program on Frontal Lobe Cognitive Function in Elders

The purpose of this study was to identify the effects of an exercise program on frontal lobe cognitive function in seniors. The participants were 42 seniors using a health center in Seoul (experimental group) and 28 seniors using a facility for elders in Seoul (control group). The exercise program was carried out for 16 weeks from April to August 2007. The frontal lobe cognitive function, which includes short term memory, attention, immediate memory, delayed memory, verbal fluency and motor function, was measured by the Digit Span Forward test, Trail Making test, Immediate recall words test, Delayed recall words, Controlled oral word association test and Finger tapping test. The collected data were analyzed by Fisher's exact test, Chi-square, t-test, and ANCOVA using the SAS program. The major findings of this study were as follows: Attention (p=.009), immediate memory (p=.005), delayed memory (p=.009), and verbal fluency (p=.004) improved after the exercise program. In this study, the exercise program was effective in improving frontal lobe cognitive function in elders. So it provides basic information for further nursing education on exercise programs which will be effective for prevention of early cognitive function decline in normally aging elders.

Effects of an Exercise Program on Frontal Lobe Cognitive Function in Elders

Purpose: The purpose of this study was to identify the effects of an exercise program on frontal lobe cognitive function in seniors. Methods: The participants were 42 seniors using a health center in Seoul (experimental group) and 28 seniors using a facility for elders in Seoul (control group). The exercise program was carried out for 16 weeks from April to August 2007. The frontal lobe cognitive function, which includes short term memory, attention, immediate memory, delayed memory, verbal fluency and motor function, was measured by the Digit Span Forward test, Trail Making test, Immediate recall words test, Delayed recall words, Controlled oral word association test and Finger tapping test. The collected data were analyzed by Fisher’s exact test, Chi-square, t-test, and ANCOVA using the SAS program. Results: The major findings of this study were as follows: Attention (p=.009), immediate memory (p=.005), delayed memory (p=.009), and verbal fluency (p=.004) improved after the exercise program. Conclusion: In this study, the exercise program was effective in improving frontal lobe cognitive function in elders. So it provides basic information for further nursing education on exercise programs which will be effective for prevention of early cognitive function decline in normally aging elders.

Relationship of Striatal Dopamine Synthesis Capacity to Age and Cognition

Past research has demonstrated that performance on frontal lobe-dependent tasks is associated with dopamine system integrity and that various dopamine system deficits occur with aging. The positron emission tomography (PET) radiotracer 6-[(18)F]fluoro-l-m-tyrosine (FMT) is a substrate of the dopamine-synthesizing enzyme, aromatic amino acid decarboxylase (AADC). Studies using 6-[(18)F]fluorodopa (FDOPA) (another AADC substrate) to measure how striatal PET signal and age relate have had inconsistent outcomes. The varying results occur in part from tracer processing that renders FDOPA signal subject to aspects of postrelease metabolism, which may themselves change with aging. In contrast, FMT remains a purer measure of AADC function. We used partial volume-corrected FMT PET scans to measure age-related striatal dopamine synthesis capacity in 21 older (mean, 66.9) and 16 younger (mean, 22.8) healthy adults. We also investigated how striatal FMT signal related to a cognitive measure of frontal lobe function. Older adults showed significantly greater striatal FMT signal than younger adults. Within the older group, FMT signal in dorsal caudate (DCA) and dorsal putamen was greater with age, suggesting compensation for deficits elsewhere in the dopamine system. In younger adults, FMT signal in DCA was lower with age, likely related to ongoing developmental processes. Younger adults who performed worse on tests of frontal lobe function showed greater FMT signal in right DCA, independent of age effects. Our data suggest that higher striatal FMT signal represents nonoptimal dopamine processing. They further support a relationship between striatal dopamine processing and frontal lobe cognitive function.

Relative contributions of the cerebellar vermis and prefrontal lobe volumes on cognitive function across the adult lifespan

Recent research has revealed significant relationships between the vermian regions of the cerebellum and cognitive functions typically associated with prefrontal lobe function. These relationships are believed to be supported by anatomical connections between the distant brain regions. Recent evidence also suggests that age-related reductions in the posterior vermis are associated with age-related decline in frontal lobe cognitive functions, but these studies did not consider concomitant age-related atrophy of the prefrontal lobes. In the present study we addressed this issue by examining cognitive and structural MRI data obtained from 251 adults ranging in age from 18 to 79. Cognition was examined with a computerized cognitive battery and volumes of the cerebellar vermian regions and the prefrontal lobes were determined using quantitative morphometry. Results of the study revealed that both prefrontal and vermian volumes were smaller in older adults compared to younger adults, and both volumes correlated with cognitive performances in the older individuals. However, after controlling for prefrontal volume, the relationships between cognitive function and vermian volumes were eliminated, whereas prefrontal lobe volume remained significantly related to cognitive function after controlling for vermian volumes. These results suggest that while a reduction in cerebellar vermian volume does not significantly relate to normal age-related cognitive decline, prefrontal volume is significantly related to cognitive aging. Our results are consistent with the frontal aging hypothesis.

Paratonia and Frontal Lobe Cognitive Function

Paratonia, an alteration of tone to passive movement, was assessed in 25 adult patients with degenerative dementia and correlated with other tests of frontal lobe function (echopraxia, distractibility, word fluency) and cognitive function (Mini-Mental State Examination) in a study at Ohio State University Medical Center, Columbus, OH.

Hereditary form of parkinsonism--dementia.

In four generations of a family, 13 members were afflicted with an autosomal dominant disorder characterized by young age at onset, early weight loss, and rapidly progressive dopa-responsive parkinsonism, followed later by dementia and, in some, by hypotension. Intellectual dysfunction began with subjective memory loss and objective visuospatial dysfunction and was followed later by decline of frontal lobe cognitive and memory functions. Neuropathological examination in 4 autopsied cases showed neuronal loss in the substantia nigra and locus ceruleus and widespread Lewy bodies, many of them in the cerebral cortex; those in the hypothalamus and locus ceruleus were often of bizarre shapes. Other findings were vacuolation of the temporal cortex, unusual neuronal loss and gliosis in the hippocampus (CA 2/3), and neuronal loss in the nucleus basalis. There were no neuritic plaques, neurofibrillary tangles, or amyloid deposits. Positron emission tomography in 3 patients showed decreased striatal uptake of fluorodopa. Neurochemical analysis of an autopsied brain showed a pronounced decrease in choline acetyltransferase activity in the frontal and temporal cortices and hippocampus and a severe depletion of striatal dopamine with a pattern not typical of classic Parkinson's disease.

The effect of white matter hyperintensity volume on brain structure, cognitive performance, and cerebral metabolism of glucose in 51 healthy adults.

To assess the association of MRI white matter hyperintensities (WMHI) with cognitive performance, cerebral structure, and cerebral metabolism in 51 healthy individuals aged 19 to 91 years without cerebrovascular risk factors. Abnormal white matter signals have been associated with brain atrophy, reduced cerebral blood flow, focal neurologic signs, gait disorder, and poorer neuropsychological test performance. Most studies of WMHI, however, include subjects with hypertension or other identifiable causes of cerebrovascular disease that may have an independent effect on brain structure and function. To assess brain changes associated with WMHI independent of cerebrovascular risk factors, we determined WMHI volume, brain volume, cerebral metabolism, and cognitive performance for a group of subjects free of medical illness. Regional cerebral metabolism and cognitive domains were also assessed to evaluate the possible role of frontal lobe dysfunction in subjects with WMHI. Cross-sectional study of 51 very healthy subjects aged 19 to 91 years. WMHI, brain, and CSF volumes were determined by MRI segmentation. Neuropsychological tests were employed to assess multiple cognitive domains. Brain metabolism was determined from 18-fluoro-2-deoxy-D-glucose PET. Multivariate relations were tested with stepwise linear regression. Models included the potential confounders of age and education where appropriate. The distribution of WMHI volume was bimodal, with five subjects having WMHI volumes beyond three SDs from the normally distributed population. A WMHI volume of greater than 0.5% of intracranial volume was considered abnormal. Within the multivariate models, WMHI volumes were significantly predictive of increased ventricular volume, reduced brain volume, and reduced cognitive scores. Subjects with greater than 0.5% WMHI volume also had significantly lower frontal lobe metabolism, significantly higher systolic blood pressure, significantly larger ventricular volume, and significantly lower scores on frontal lobe-mediated neuropsychological tests than age-matched controls. WMHI volume is associated with structural and functional brain changes even within a group of very healthy individuals. WMHI is associated with poorer frontal lobe cognitive function and, when severe, is accompanied by significantly reduced frontal lobe metabolism. Subjects with large WMHI volumes have significantly higher systolic blood pressure, brain atrophy, reduced cerebral metabolism, and lower scores on tests of frontal lobe function than age-matched controls. Large amounts of WMHI are, therefore, pathologic and may be related to elevated systolic blood pressure even when it is within the normal age-related range.

Frontal lobe cognitive functions in aging: methodologic considerations.

The empirical literature has been contradictory regarding whether frontal functions decline with age, perhaps due to important differences across studies in medical and psychiatric exclusion criteria. We review literature and present preliminary data suggesting that frontal lobe functions are particularly affected by several medical and psychiatric disorders common in old age. Investigations of frontal lobe functions in aging require careful screening of subject samples; otherwise, any impact of age on cognition is contaminated by the effects of coexistent physical and/or psychiatric illness.

Cerebral metabolic and cognitive studies in dementia with frontal lobe behavioral features

Three subjects with dementia of the Alzheimer type (DAT) with frontal lobe features of behavioral disinhibition were studied using positron emission tomography with [18F]2-fluoro-2-deoxy-D-glucose (18 FDG) and standardized neuropsychological tests. The three subjects showed significant decrements ( p < .05) in relative glucose metabolism (regional/mean gray metabolism) in the orbitofrontal, prefrontal and anterior cingulate regions when compared to healthy controls. Severity-matched subjects with DAT without the associated frontal lobe features did not show the relative reductions in glucose metabolism in these regions when compared to controls. However, on neuropsychological testing of frontal lobe cognitive functions the three subjects did not show decrements that were more severe than those shown by severity-matched DAT patients without the behavioral features. These data demonstrate physiologic dysfunction in specific cortical regions in subjects with behavioral aberrations attributed to these regions and an apparent dissociation between behavioral and cognitive functions of the frontal lobe.