Go - no go learning after frontal lobe lesions in humans.

48 patients with unilateral frontal or non-frontal cortical lesions were given a go - no go learning task. Patients with frontal lesions in either hemisphere took longer to learn the task and made more false "go" responses than control patients. They also, unlike controls, took longer to make in correct positive responses than correct positive ones. Medial frontal lesions were found to be particularly important in giving rise to poor performance on this task. It is suggested that this task is non-unitary in nature and that the medial area may be important for more than one ability.     

Disruption of attention to novel events after frontal lobe injury in humans

OBJECTIVE: To investigate whether frontal lobe damage in humans disrupts the natural tendency to preferentially attend to novel visual events in the environment. METHODS: Nine patients with chronic infarctions in the dorsolateral prefrontal cortex (DLPFC) and 23 matched normal controls participated in a study in which subjects viewed repetitive background stimuli, infrequent target stimuli, and novel visual stimuli (for example, fragmented or "impossible" objects). Subjects controlled viewing duration by a button press that led to the onset of the next stimulus. They also responded to targets by pressing a foot pedal. The amount of time spent looking at the different kinds of stimuli, and the target detection accuracy and speed served as dependent variables. RESULTS: Overall, normal controls spent significantly more time than frontal lobe patients looking at novel stimuli. Analysis of responses across blocks showed that initially frontal lobe patients behaved like normal controls by directing more attention to novel than background stimuli. However, they quickly began to distribute their viewing time evenly between novel and background stimuli, a pattern that was strikingly different from normal controls. By contrast, there were no differences between frontal lobe patients and normal controls for viewing duration devoted to background and target stimuli, target detection accuracy, or reaction time to targets. Frontal lobe patients did not differ from normal controls in terms of age, education, estimated IQ, or mood, but were more apathetic as measured by self report and informants' judgments. Attenuated responses to novel stimuli significantly correlated with degree of apathy. CONCLUSIONS: This study demonstrates that DLPFC injury selectively impairs the natural tendency to seek stimulation from novel and unusual stimuli. These data provide the first quantitative behavioural demonstration that the human frontal lobes play a critical part in directing and sustaining attention to novel events. The impairment of novelty seeking behaviour may contribute to the characteristic apathy found in patients with frontal lobe injury.     

Electrophysiology of the frontal lobe.

The electrophysiology of the frontal lobe appears to be unimpressive when the view is limited to the routine EEG recording of a healthy waking adult. There is usually low voltage fast activity, which becomes more pronounced when recorded with depth leads. Three special EEG patterns of marginal to slightly abnormal character are discussed: a) rhythmical midfrontal 6-7/sec activity of juveniles, b) rhythmical midfrontal sharp 4-6/sec activity of infancy and early childhood with arousal from sleep, and c) frontal intermittent rhythmical delta activity (FIRDA) in waking adults with frontopolar maximum, possibly related to thought processes under abnormal conditions. With extension of the frequency range, ultraslow (DC-like) as well as fast beta (gamma, 40-80/sec) and ultrafast activity (80-1000/sec) are found particularly over the frontal lobes. Ultraslow baseline shifts are arousal-related and mixed with overlying ultrafast waves. Attention control and the "working memory" involve chiefly the dorsolateral prefrontal cortex, investigated with P300 responses and likely to show ultrafast spectra. Perception-related 40-80/sec gamma activity has been thought to be associated with the entrance into consciousness. Initiation and design of motor activity spreads from prefrontal to the frontomotor cortex, associated with powerful event-related potentials: contingent negative variation (CNV) and "Bereitschafts potential" ("readiness potential," RP). Neuroscientific research of the highest frontal lobe functions has become a very active domain of neuroimaging. With the use of the extended frequency range, EEG and also evoked potential studies could add further information with acquisition in real time. Ultrafast frequency ranges presented in computerized frequency analysis and mapping might show impressive correlates of highest frontal lobe functions.     

Dementia of frontal lobe type.

A significant proportion of patients with presenile dementia due to primary cerebral atrophy do not have Alzheimer's disease. One form of non-Alzheimer dementia may be designated as dementia of frontal lobe type (DFT), on the basis of a characteristic neuropsychological picture suggestive of frontal lobe disorder, confirmed by findings on single photon emission tomography. The case histories of seven patients exemplify the disorder: a presentation of social misconduct and personality change, unconcern and disinhibition, in the presence of physical well-being and few neurological signs. Assessment revealed economic and concrete speech with verbal stereotypes, variable memory impairment, and marked abnormalities on tasks sensitive to frontal lobe function. Visuo-spatial disorder was invariably absent. Comparisons of DFT and Alzheimer patients revealed qualitative differences in clinical presentation, neurological signs, profile of psychological disability, electroencephalography, single photon emission tomography and demography. DFT, which may represent forms of Pick's disease, may be more common than is often recognised.     

Neuropsychological performance in frontal lobe epilepsy.

The search for a special neuropsychological profile of frontal lobe epilepsy subjects (FLE) has so far led to inconclusive results. In this paper we compared the preoperative neuropsychological performance of FLE and temporal lobe epilepsy (TLE) subjects. We further investigated whether frontal lobe lesions of epileptogenic cause produce the same type of cognitive dysfunction as do tumours of the frontal lobe. Sixteen FLE subjects were compared to 16 TLE subjects as well as to a group of 10 subjects after the removal of frontal lobe tumors (TUM) and a healthy control group. A set of neuropsychological test measures routinely used for presurgical evaluation, an emotional conceptualization task and two associative learning tasks were administered. We found that subjects with frontal lobe damage were significantly impaired relative to controls on a wide range of cognitive functions independent of neurological cause. FLE subjects could hardly be discriminated from TLE subjects as both groups showed a similarly reduced level of neuropsychological performance. Our results demonstrate the devastating effect that frontal lobe epilepsy can have on cognitive functioning. Routinely used neuropsychological test measures lack the specificity to distinguish between frontal and temporal lobe epilepsy. Highly specialized measures are necessary to reveal differences.     

Planning impairments in frontal lobe dementia and frontal lobe lesion patients

Patients with frontal lobe brain damage are reportedly impaired on tasks that require plan development and execution. In this study, we examined the performance of 15 patients diagnosed with frontal lobe dementia and 14 patients with focal frontal lobe lesions on the Tower of London planning task. Patients with frontal lobe dementia committed a significantly higher number of rule violations, made more moves, and demonstrated longer solution time latencies compared to their matched controls. Patients with frontal lobe lesions demonstrated significantly delayed solution times and also made more moves compared to their matched controls. Frontal lobe lesion patient performance suggests an impairment in execution-related processes, while frontal lobe dementia patients appear to be impaired in both plan development and execution. Despite these findings, the identification of a specific cognitive impairment that induces these planning problems remains elusive.     

Catatonia with frontal lobe atrophy.

A middleaged woman with a four year history of behavioural change including episodes of catatonia is described. Despite a persistently abnormal electroencephalogram, the patient was diagnosed repeatedly as suffering from a primary psychiatric disorder. Neurological examination and psychological testing suggested frontal lobe dysfunction, which was confirmed by the finding of isolated frontal lobe atrophy on computed axial tomography.     

Akinesia and the frontal lobe.

A report of severe akinetic episodes in patients with Parkinson disease (PD) has been the stimulus for the following discussion of akinesia and its variants. Severe persistent akinesia may occur in frontal lobe impairment. Therefore, it is likely that extension of the Parkinsonian dysfunction into the frontal lobe causes severe akinesia which should be separated from the very common Parkinsonian hypokinesia. Another very common clinical phenomenon of PD is sudden freezing. Hence the frontal lobe--hardly regarded as a region of special interest in the realm of PD--can be the cause of severe and dangerous complications of PD. The term "arrest reaction" or "motor arrest" denotes a similar freezing. It is recommended to restrict these terms to certain forms of frontal lobe epilepsy. This discussion of hypokinetic and akinetic states should also include catatonia: a form of schizophrenia with a special type of akinesia. Though without major neuropathological substratum, this condition can, in extremely rare cases, lead to severe hyperthermia and fatal outcome (presumably via hypothalamic dysfunction).     

Confabulation and frontal lobe dysfunction.

A patient is reported who displayed marked confabulation after frontal lobe damage, and whose pattern of performance on memory tests was not typically amnesic. He initially displayed both "fantastic" and "momentary" confabulation, but several months later showed only "momentary" confabulation, which was apparent on direct questioning. This change in type of confabulation was paralleled by improved performance on frontal lobe tests, although his overall pattern of performance on memory tests was unchanged. It is suggested that severity of frontal lobe dysfunction determines the type of confabulation displayed.     

Neuropsychologic assessment of frontal lobe dysfunction.

Given the pervasive nature of executive deficit, assessment of executive functions is of crucial importance in neuropsychiatry, child and adolescent psychiatry, geriatric psychiatry, and other related areas. A number of neuropsychologic tests of executive function commonly are used in assessing several clinical disorders, including but not limited to traumatic brain injury, schizophrenia, depression, attention deficit disorder/attention deficit hyperactivity disorder, and dementia. Because the concept of executive control in its current form constitutes an over arching construct, a construct that is based on the cognitive symptoms of the frontal lobe disorder caused by many disparate underlying conditions, no single measure of executive function can adequately tap the construct in its entirety.Therefore, it is necessary to administer several tests of executive function,each assessing a particular aspect of the executive function. An appropriate combination of such neuropsychologic tests and batteries, including the Wisconsin Card Sorting Test, Tower test, Stroop test, the D-KEFS, and the ECB, provides an adequate but relatively crude mechanism for assessing executive systems dysfunction. Neuroscientists continue to refine their understanding of the nature of executive control, and additional innovative procedures that reflect state-of-the-art insights of cognitive neuroscience have been introduced recently. Among a few first steps in that direction are nonveridical, actor-centered procedures such as the CBT and the Iowa Gambling Test.     

Examination by near-infrared spectroscopy for evaluation of piano performance as a frontal lobe activation task

The purpose of this study was to reveal the activation of the frontal lobe in piano performance by the use of near-infrared spectroscopy. Participants wereseven healthy volunteer music college students. The results of the examination showed a tendency towards an increase in total hemoglobin volume over a wider area in the frontal part of the brain during an appropriate piano task compared with an easy piano task or the Keio version of the Wisconsin Card Sorting Test. The results suggest that piano performance is recognized as a frontal lobe-activating task and that performance of an appropriate piano task can be expected to elicit wider activation of the frontal lobe than an easy one.     

Electric source imaging in frontal lobe epilepsy.

The objective of this study was to determine the validity of interictal spike (IIS) source localization in frontal lobe epilepsies (FLE) using stereoelectroencephalography as a validating method. Ten patients with drug-resistant FLE were studied with high-resolution EEG and stereoelectroencephalography. Sixty-four scalp channels, a realistic head model, and different algorithms were used. For each patient, the intracerebral interictal distribution was studied and classified into one of three groups: lateral, medial, and mixed (latero-medio-basal). Surface IIS were abundant or subcontinuous for 8 of 10 FLE patients. In lateral and medial groups, intracerebral interictal activities were accurately localized. In the mixed group, source localizations designated a part of the intracerebral interictal distribution. A high degree of source localization accuracy is obtained in FLE. False-positive results were never obtained, but the extent of interictal activity could be underestimated by source localization results. Geometrical and cytoarchitectonic characteristics of the generator appear crucial to explain why medial frontal IIS (anterior para-cingulate gyrus and anterior cingulate gyrus) may be localizable whereas only the lateral orbitofrontal IIS seems to be localizable.     

Automatisms during frontal lobe epileptic seizures.

Three new cases of automatisms occurring during frontal lobe epileptic seizures are reported. If these cases are added to those already published and adequately described in the literature, a total of 12 cases is obtained. An attempt is made to elucidate the clinical characteristics of automatisms encountered during frontal lobe seizures. This kind of automatism would seem to be clinically distinguishable from other types.     

Absence seizures and the frontal lobe.

There is no doubt that the frontal lobe plays a major role in the 3/sec spike-wave absence seizure. It is pointed out initially that the controversies of cortical vs. thalamic origin of the spike-waves and the associated absence can be laid at rest as far as human absence seizures and human primary generalized epilepsy (PGE) are concerned: their origin is cortical with maximal frontal lobe involvement. Experimentally-induced spike-wave bursts or spontaneous spike-waves in animals pertain to other forms of epileptic seizure disorder. The frontal maximum of the 3/sec spike-wave pattern indeed indicates maximal frontal lobe involvement including both prefrontal and frontomotor portions. The absence as such is presumed to be a suspension of the working memory--an eminently frontal lobe function. This explains the immediate restoration of ictally-impaired neurocognitive functions right at the termination of the seizures. This concept can be applied not only to the classical absence occurring in PGE but also to the rare cases of secondary bilateral synchrony with a primary frontal epileptogenic focus leading to true (though very slightly different) absences.     

Dementia of frontal lobe type in Kennedy's disease.

The pathomorphological correlate of Kennedy's disease (KD) is a degeneration of spinal and bulbar alpha-motor neurons. The disease is caused by a CAG repeat expansion in the first exon of the X-chromosomal androgene receptor gene. Contrary to the common belief that cognitive disorders in motor neuron diseases (MND) are either rare or only mild, there is now an increasing number of case reports on dementia in amyotrophic lateral sclerosis (ALS). In ALS, dementia of the frontal lobe type (frontotemporal dementia, FTD) seems to be the characteristic pattern. However, in KD cognitive dysfunction has not been studied systematically. Here we present a case with clinical characteristics of FTD in a patient with genetically confirmed KD. It remains speculative whether there is an association between KD and FTD comparable to a genetic linkage between ALS and FTD, which has been proposed in recent years. However, we suggest that cognitive dysfunction may be more common in KD than reported until today.     

Topiramate in frontal lobe epilepsy

BACKGROUND: Frontal lobe epilepsy (FLE) is a type of epilepsy that is difficult to treat and there are few studies about the use of topiramate (TPM). AIM OF THE STUDY: To evaluate the efficacy and tolerability of TPM monotherapy in FLE. METHODS: The study group consisted of 55 (33 male; 22 female) patients. TPM was administered as a first drug (n = 16) or converted after previous treatment (n = 39). All patients were followed every 3 months for at least 1 year. The patients were subdivided into two groups: 'newly diagnosed' patients and 'difficult-to-treat' patients. RESULTS: Overall, all patients completed the 1-year study. At the end of follow-up, 10 patients showed disappearance of seizures and 33 patients showed improvement in seizure frequency. In particular, among the newly diagnosed patients 6/16 patients showed complete cessation of seizures and 5/16 patients showed very good response; in the other group, 4/39 patients showed complete cessation and 4/39 patients showed a very good response. No patients of both groups had worsening of seizures. No treatment-limiting adverse events associated with TPM were reported. CONCLUSIONS: TPM is effective in newly diagnosed patients with FLE; TPM can be considered for the treatment of FLE.