Dominant Parietal Lobe Research Articles

Gerstmann Syndrome Case-Control Study: Correlation between Brain Lesions & Functional Disability.

Deep functional and structural neuroimaging of a series of Gerstmann's syndrome patients required high accuracy, and our results avoided false overlaps of heterogeneous brain lesions by handling each case of our study subjects separately as an individual case regarding functional and neuroimaging tests. Six patients with Gerstmann tetrad (one with dominant acalculia, one with dominant left and right disorientation, two with writing disabilities and two with finger agnosia) and 6 control subjects with close ages were recruited in the current study. In the main phase, we assessed brain activation in response to experimental and interventional settings using neuroimaging techniques (FMRI-Functional Magnetic Resonance Imagingwhere twelve pictures were taken on a Dell inspiration 3T all-body scanner with sequences of echo pictures, 80o angled, TE 35 ms) of the subject's brain to declare lesions existence and locations that might result in one of the four cognitive impairment domains of Gerstman's syndrome tetrad. We assessed statistically significant differences of patient images vs. control images as well as the images of patients presenting specific symptomatic cognitive dysfunction domain vs. the images of patients presenting the three other domains. Neuroimages were analyzed using multiple databases such as T1 weighted and free sequence types. Gerstmann's syndrome is mainly connected to injury in the dominant parietal lobe, so images comparisons and analysis were only restricted to the left parietal lobe region. P values <0.05were only considered as statistically significant difference in comparisons of functional tests time and accuracy of patients vs. in addition to comparisons of brain images parameters of patient group vs. control group and specific symptomatic domain patients vs. other symptomatic domains patients. Regarding functional testing, Patients group took significantly higher time compared to control group. Regarding brain images parameters, patients in each domain showed significantly different lesions compared to other domains. Moreover, control subjects showed no lesions in the left parietal lobe compared to significant lesions in the patient groups. These results oppose the theory of Gerstmann that a common brain structural injury may result in the combination of all of the four symptomatic dysfunction domains. This may be due to the fact that Gerstmann examined incomplete cases which represent a considerable criticism to his scientific basis. Moreover, he excluded patients with speech difficulties and apraxia.

Dominant Parietal Lobe Ischaemic Stroke Presenting as Alien Hand Syndrome

We describe an unusual case of stroke manifesting as alien hand syndrome (AHS) causing sudden onset of abnormal hand movements. The patient reported his left arm would move outside his control and grab things in his surroundings without his conscious will. He felt his arm did not belong to him. Examination showed left arm brisk reflexes, astereognosis, and agraphesthesia in the left hand. Imaging revealed an established right parietal lobe ischaemic stroke. Lesions of the parietal cortex can cause AHS by disrupting the interpretation of somatosensory feedback when a movement is made and decreasing the ability to consciously monitor motor intentions. A low threshold should be adopted for arranging brain imaging and a thorough neurological examination is needed in any sudden onset movement disorder.

A Tetrad Cognitive Presentation of Gerstmann Syndrome: A Rare Manifestation of Stroke

Gerstmann Syndrome is a rare neurological presentation due to a lesion in the left dominant parietal lobe, manifesting as a tetrad of agraphia, acalculia, finger agnosia and right-left disorientation. We present a case of a 52-year-old man, right hand dominant, who presented to the Emergency Department with acute confusion for one day. He was disorientated to time, place and person. Focused neurological examination revealed atypical signs of acute stroke, comprising agraphia, acalculia, finger agnosia and right-left disorientation. Stroke protocol was activated and he underwent computed tomography brain perfusion, which confirmed a large penumbra area at the left middle cerebral artery territory. Computed tomography angiogram of the carotid arteries showed a long segment thrombosis in the left internal carotid artery. Emergency thrombectomy was abandoned due to impenetrable hard thrombus. He was treated with dual antiplatelet therapy and discharged after three days with partial improvement in terms of following commands, simple calculations and reduced finger agnosia. He was scheduled for outpatient follow up. This case highlights Gerstmann syndrome as an atypical manifestation of acute stroke.

Two different subcortical language networks supporting distinct Japanese orthographies: morphograms and phonograms.

Language systems worldwide are based on either morphograms or phonograms, but Japanese is unique in that uses a complicated combination of kanji (morphogram) and kana (phonogram) characters. The white matter networks associated with reading have been investigated previously but remain incompletely understood. In this study, we performed intraoperative language mapping under local anesthesia and postoperative language assessments of 53 consecutive patients who underwent awake craniotomy for surgical resection of cerebral glioma within the dominant temporal or parietal lobe. Six cases showing intraoperative dyslexia elicited by direct electrical stimulation (DES) were examined, and all cases showed transient symptoms of kanji or kana dyslexia during DES. We investigated the intraoperative positive mapping points localized near four white matter bundles: the arcuate fascicle, posterior superior longitudinal fascicle, inferior fronto-occipital longitudinal fascicle, and inferior longitudinal fascicle (ILF). The intraoperative DES distributions for kanji dyslexia were especially associated with the anterior-inferior side of the ILF. On the other hand, the DES points associated with kana dyslexia were localized on the posterior-superior side of the complex composed of these four tracts. These results suggest the presence of specific non-interfering networks that subserve the processes of reading morphograms and phonograms.

Crossed Aphasia after Intracranial Hematoma in the Right Temporoparietal Lobe: A Case Report

Purpose: Aphasia in a dextral after right hemisphere injury is called crossed aphasia (CA). We are reporting a first case of transformation of motor aphasia to conduction aphasia after right hemisphere intracerebral hemorrhage (ICH) associated with arteriovenous malformation (AVM) with literature reviews.Methods: A case of a man in his 30s with CA following right hemisphere ICH in the temporal-parietal lobe associated with AVM was reviewed. We analyzed his brain images, initial linguistic characteristics, and changes in aphasia for 8 weeks of follow-up.Results: The initial Paradise Korean Western Aphasia Battery Revised (PK-WAB-R) was evaluated as aphasia quotient (AQ) 72, 64%ile; post evaluation was evaluated AQ 95, 98.9%ile after 8 weeks. The post-test repetition score was the patient score range, which can be attributed to impairment in phonological short-term memory. The patient is diagnosed anomalous CA based on Alexander et al., and we could predict that the language ability originates from both hemispheres based on Nagaraja et al. Considering the appearance of Gerstmann syndrome at the beginning of the onset, we could expect that the function of the dominant parietal lobe is partially crossed as well.Conclusion: Changes in aphasia were reported throughout the initial stage to the end of speech therapy. It is also important to note that literature review of Korean studies was analyzed in this study. It will be necessary to conduct a cognitive test in the early stage of onset to understand the language problems of crossed conduction aphasia to know the characteristics of the cognitive process.

Lewy Body Disease is a Contributor to Logopenic Progressive Aphasia Phenotype.

The objective of this study was to describe clinical features, [18 F]-fluorodeoxyglucose (FDG)-positron emission tomography (PET) metabolism and digital pathology in patients with logopenic progressive aphasia (LPA) and pathologic diagnosis of diffuse Lewy body disease (DLBD) and compare to patients with LPA with other pathologies, as well as patients with classical features of probable dementia with Lewy bodies (pDLB). This is a clinicopathologic case-control study of 45 patients, including 20 prospectively recruited patients with LPA among whom 6 were diagnosed with LPA-DLBD. We analyzed clinical features and compared FDG-PET metabolism in LPA-DLBD to an independent group of patients with clinical pDLB and regional α-synuclein burden on digital pathology to a second independent group of autopsied patients with DLBD pathology and antemortem pDLB (DLB-DLBD). All patients with LPA-DLBD were men. Neurological, speech, and neuropsychological characteristics were similar across LPA-DLBD, LPA-Alzheimer's disease (LPA-AD), and LPA-frontotemporal lobar degeneration (LPA-FTLD). Genetic screening of AD, DLBD, and FTLD linked genes were negative with the exception of APOE ε4 allele present in 83% of LPA-DLBD patients. Seventy-five percent of the patients with LPA-DLBD showed a parietal-dominant pattern of hy pometabolism; LPA-FTLD - temporal-dominant pattern, whereas LPA-AD showed heterogeneous patterns of hypometabolism. LPA-DLBD had more asymmetrical hypometabolism affecting frontal lobes, with relatively spared occipital lobe in the nondominantly affected hemisphere, compared to pDLB. LPA-DLBD had minimal atrophy on gross brain examination, higher cortical Lewy body counts, and higher α-synuclein burden in the middle frontal and inferior parietal cortices compared to DLB-DLBD. Whereas AD is the most frequent underlying pathology of LPA, DLBD can also be present and may contribute to the LPA phenotype possibly due to α-synuclein-associated functional impairment of the dominant parietal lobe. ANN NEUROL 2021;89:520-533.

Gerstmann syndrome as a disconnection syndrome, evidence from DTI tractography: A case report

Gerstmann's syndrome is a syndrome caused by lesions of the dominant parietal lobe. It has historically been a subject of dispute as it is often accompanied by other neuropsychological deficits such as aphasia. Novel neuropsychological tests and neuroimaging techniques have lately changed the perspective allowing to decode a conjunction of symptoms like Gerstmann's. In our case, we present Diffusion Tensor Imaging Tractography findings of a patient who acutely exhibited Gerstmann's tetrad. Using advanced structural neuroimaging we tested a hypothesis that up until recently could only be challenged post mortem. Our study offers much needed patient neuroimaging data helping to establish Gerstmann's as a disconnection syndrome. More reports of Gerstmann's syndrome patients including high resolution tractography and fMRI data are needed.

Abstract 697: Improvement in quality and length of life following treatment with mifepristone in women with stage IV non-small cell lung cancer, positive for the epidermal growth factor receptor (EGFR) mutation, that previously progressed on targeted therapy

Abstract Treatment with the oral single agent progesterone receptor modulator, mifepristone, has been demonstrated to significantly increase the quality and length of life in a patient with stage IV non-small cell lung cancer (NSCLC) that progressed despite multiple rounds of chemotherapy, when no markers existed for specific targeted therapy. The purpose of the present study was to determine if mifepristone could similarly provide palliative benefits to patients with NSCLC, that were positive for EGFR mutation, who had progressed despite targeted therapies. Patient 1, a 59 year old woman presented with 6 months of upper back pain and dyspnea, was found to have innumerable tiny lung nodules (miliary pattern), bone metastases, and a single brain metastasis (left occipital lobe). The tumor was an adenocarcinoma, with an EGFR exon leu858 arg identified. The brain metastasis was treated with palliative radiation therapy and erlotinib was started. She remained stable for 1 ½ years, but then her lung nodules started to increase in size. Erolotinib was stopped, and osimertinib was started. However, she progressed 6 months later, with continued growth of pulmonary nodules bilaterally and a new brain metastasis, in the right lateral cuneus. Her dyspnea, which had improved on erlotinib, returned to pre-treatment status. She was started on oral single agent mifepristone, 200mg per day. Patient 2, a 46 year old woman, had presented with headaches, difficulty with executive function, and memory loss. She was diagnosed with stage IV NSCLC, with extensive lung lesions and brain metastases. A MRI of the brain revealed innumerable supratentorial rim enhancing lesions, with one dominant left parietal lobe lesion measuring 3 × 2.1cm (treated with palliative radiation). CT scans showed innumerable bilateral pulmonary nodules with evidence of lymphangitic spread and multiple bone lesions. Because the tumor was positive for the EGFR1 exon 19 mutations (E746/751 mutation), she was started on afatinib, which was stopped 8 months later. She then had a second course of brain radiation and 5 months after stopping afatinib she began osimertinib. After 10 months of osimertinib, it seemed to be losing effectiveness, and so 200mg oral mifepristone was added. Both women have had stable disease, with no growth of previous nodules and no new nodules, or new brain metastases after 6 months and 14 months of mifepristone therapy, respectively. More importantly they both feel much better, with no dyspnea, or pain, and remain ECOG-0. Thus, similar to small cell lung cancer and NSCLC devoid of tumor markers, or with the PD-L1 mutation, patients with advanced NSCLC with EGFR mutation also seem to respond to the progesterone receptor modulator, mifepristone. Citation Format: Jerome H. Check, Diane Check, Trina Poretta, James Aikins, Carrie Wilson. Improvement in quality and length of life following treatment with mifepristone in women with stage IV non-small cell lung cancer, positive for the epidermal growth factor receptor (EGFR) mutation, that previously progressed on targeted therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 697.

Plasticity in language cortex and white matter tracts after resection of dominant inferior parietal lobule arteriovenous malformations: a combined fMRI and DTI study.

The dominant inferior parietal lobe (IPL) contains cortical and subcortical structures that serve language processing. A high incidence of postoperative short-term aphasia and good potential for language reorganization have been observed. The authors' goal was to study the plasticity of the language cortex and language-related fibers in patients with brain arteriovenous malformations (BAVMs) located in the IPL. A total of 6 patients who underwent microsurgical treatment of an IPL BAVM were prospectively recruited between September 2016 and May 2018. Blood oxygen level-dependent functional MRI (BOLD-fMRI) and diffusion tensor imaging (DTI) were performed within 1 week before and 6 months after microsurgery. Language-related white matter (WM) eloquent fiber tracts and their contralateral homologous fiber tracts were tracked. The Western Aphasia Battery was administered to assess language function. The authors determined the total number of fibers and mean fractional anisotropy (FA) indices for each individual tract. In addition, they calculated the laterality index (LI) between the activated language cortex voxels in the lesional and contralesional hemispheres and compared these indices between the preoperative and postoperative fMR and DT images. Of the 6 patients with IPL BAVMs, all experienced postoperative short-term language deficits, and 5 (83.3%) recovered completely at 6 months after surgery. Five patients (83.3%) had right homologous reorganization of BOLD signal activations in both Broca's and Wernicke's areas. More fibers were observed in the arcuate fasciculus (AF) in the lesional hemisphere than in the contralesional hemisphere (1905 vs 254 fibers, p = 0.035). Six months after surgery, a significantly increased number of fibers was seen in the right hemispheric AF (249 fibers preoperatively vs 485 postoperatively, p = 0.026). There were significantly more nerve fibers in the postoperative left inferior frontooccipital fasciculus (IFOF) (874 fibers preoperatively vs 1186 postoperatively, p = 0.010). A statistically significant increase in right hemispheric dominance of Wernicke's area was observed. The overall functional LI showed functional lateralization of Wernicke's area in the right hemisphere (LI ≤ -0.20) in all patients. The authors' findings provide evidence for the functional reorganization by recruiting the right hemispheric homologous region of Broca's and Wernicke's areas, right hemispheric AFs, and left hemispheric IFOFs following resection of IPL BAVMs.Clinical trial registration no.: NCT02868008 (clinicaltrials.gov).

Neuroimaging Characteristics of Frailty Status in Patients with Alzheimer's Disease.

Although frailty is closely linked to dementia, particularly Alzheimer's disease (AD), underlying pathophysiology of frailty associated with AD remains uncertain. This study aimed to investigate differences in structural and functional brain imaging abnormalities between AD with and without frailty. A total of 191 outpatients with probable AD (men: 91; women: 100; age: 80.7±6.3 years) who underwent both magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) were enrolled in this study. Frailty was determined in accordance with the Obu study Health Promotion for the Elderly. We compared numbers of small infarctions in the subcortical gray and white matter and severity of white matter abnormalities (periventricular hyperintensity [PVH] and deep white matter hyperintensity [DWMH]) on MRI, and regional cerebral blood flow (rCBF) changes on SPECT between AD with and without frailty. The prevalence of frailty was 43.4% in patients with AD. PVH and DWMH scores were significantly higher in AD with frailty compared to those without frailty. AD with frailty had a trend of decreased rCBF in the bilateral anterior cingulate gyrus, whereas those without frailty tend to have decreased rCBF in the left dominant parietal lobe and precuneus. Our MRI and SPECT imaging studies suggest different underlying pathophysiology in the brain between AD with frailty and without frailty.

Gerstmann's Syndrome

The propose of this paper, is to tested the performing in-depth functional and structural neuroimaging in a series of Gerstmann's syndrome. Additional, to avoid spurious overlap from blurring and inter-subject brain variability we conducted our experiment at high spatial resolution and sensitivity and analyzed our findings as a series of single cases. In a mainphase, we documented brain activation in answer to experimental and management conditions that were interpreted to identify cortical candidate areas where harm would putatively outcome in one of the four indications of Gerstmann's tetrad, and after that, we verified for overlap of all four corticalshapes. In a subsequent phase, established on diffusion tensor imaging data, we operated the functional outcomes to describe seeding facts for following the white-matter associates of the activated corticalareas, and after that we were again inspected whether there was an zone of overlap among all four categorizes of whitematterpamphlets. Sex Gerstmann's syndrome volunteers (2 female, 4 male, mean age 21 years) gave penned notified agreement to contribute in the case, which was accepted by the native ethicsagency. This taster size is acceptable for the reason as well as the resources active in this case, which complicated in-depth examines in a series of particular subjects relatively to relying on collection averaging. FMRI which shortcut for (Functional magnetic resonance imaging) where twelve pictures were developed on a Dell inspiration 3T all-body scanner with an echo pictures sequence (angle 80o, TE 35 ms). To assess the statistical importance of these maps, we have addressed the issue of multiple comparisons in the following way, voluntary compromise. Since Gerstmann's syndrome is associated with the damage of the dominant parietal lobe, we have corrected the levels of importance of activation only in size within the left parietal mask. By applying the threshold corrected, we could not identify any signal of domain linked to any subjects. There was no statistical association between Gerstmann's symptoms and above that, with other signs of damage to the parietal lobe. In particular, he referred to (i) Incomplete cases and thus disintegration within the syndrome and (ii) Exclusion from a oligarchic fellowship Symptoms are often associated with loss of speech and apraxia.

Gerstmann syndrome in a young man: a case report

Gerstmann syndrome is a classical cerebral syndrome in neurology, named after Joseph Gerstmann, a Jewish Austrian-born American neurologist. Patients present with a tetrad of cognitive symptoms, including agraphia, acalculia, finger agnosia and left-right disorientation. The syndrome is known to result from a lesion of the posterior portion of the dominant parietal lobe and is usually due to stroke or to developmental problems. We describe the case of a 35-year-old man whose illness debuted about 9 months before the initial presentation to the neurology clinic, with memory complaints, anxiety, verbal aggression, sleeping problems, as well as subjective word finding difficulty and depressed mood. The patient had 3 out of the 4 classic symptoms of Gerstmann syndrome, among other, mostly neuropsychiatric symptoms. Initially, structural lesions were sought for, but were not found on magnetic resonance imaging. Psychiatric conditions were discussed but not confirmed by the consulting psychiatrist. We are prone to accepting a non-organic reason for the condition of the patient, but follow-up of the clinical course and repeated assessments, including neuropsychological and psychiatric evaluations, structural and possibly functional neuroimaging will be required to verify and confirm this presumption.

Multimodal responses induced by cortical stimulation of the parietal lobe: a stereo-electroencephalography study.

The functional complexity of the parietal lobe still represents a challenge for neurophysiological and functional neuroimaging studies. While the somatosensory functions of the anterior parietal cortex are well established, the posterior parietal cortex has a relevant role in processing the sensory information, including visuo-spatial perception, visual attention, visuo-motor transformations and other complex and not completely understood functions. We retrospectively analysed all the clinical manifestations induced by intracerebral bipolar electrical stimulation in 172 patients suffering from drug-resistant focal epilepsy (mean age 25.6, standard deviation 11.6; 44% females and 56% males) with at least one electrode stereotactically implanted in the parietal cortex. A total of 1186 electrical stimulations were included in the analysis, of which 88 were subsequently excluded because of eliciting pathological electric activity or inducing ictal symptomatology. In the dominant parietal lobe, clinical responses were observed for 56 (25%) of the low-frequency stimulations and for 76 (50%) of the high-frequency stimulations. In the non-dominant parietal lobe, 111 (27%) low-frequency and 176 (55%) high-frequency stimulations were associated with a clinical response. Body scheme alteration was the only clinical effect showing a lateralization, as they were evoked only in the non-dominant hemisphere. The occurrence of somatosensory sensations, motor symptoms, dysarthria and multimodal responses were significantly associated with stimulation of the postcentral gyrus (odds ratio: 5.83, P < 0.001; odds ratio: 8.77, P < 0.001; odds ratio: 5.44, P = 0.011; odds ratio: 8.33, P = 0.006; respectively). Stimulation of the intraparietal sulcus was associated with the occurrence of sensory illusions or hallucinations (odds ratio: 8.68, P < 0.001) and eyeball/eyelid movements or sensations (odds ratio: 4.35, P = 0.047). To our knowledge, this is the only currently available complete revision of electrical stimulation of the entire parietal cortex with the aim to evaluate the neurophysiology of this relevant brain region. Our analysis offers a general overview of the multiple roles of the parietal cortex and supports its crucial involvement in different networks related to complex integrative functions.media-1vid110.1093/brain/awv187_video_abstractawv187_video_abstract.

Functional mapping using subdural electrodes combined with monitoring during awake craniotomy enabled preservation of function and extensive resection of a glioma adjacent to the parietal lobe language sites: a case report

Surgical resection of gliomas located in the dominant parietal lobe is difficult because this lesion is surrounded by multiple functional areas. Although functional mapping during awake craniotomy is very useful for resection of gliomas adjacent to eloquent areas, the limited time available makes it difficult to sufficiently evaluate multiple functions, such as language, calculative ability, distinction of right and left sides, and finger recognition. Here, we report a case of anaplastic oligodendroglioma, which was successfully treated with a combination of functional mapping using subdural electrodes and monitoring under awake craniotomy for glioma. A 32-year-old man presented with generalized seizure. Magnetic resonance imaging revealed a non-enhanced tumor in the left angular and supramarginal gyri. In addition, the tumor showed high accumulation on 11C-methionine positron emission tomography(PET)(tumor/normal brain tissue ratio=3.20). Preparatory mapping using subdural electrodes showed absence of brain function on the tumor lesion. Surgical removal was performed using cortical mapping during awake craniotomy with an updated navigation system using intraoperative magnetic resonance imaging(MRI). The tumor was resected until aphasia was detected by functional monitoring, and the extent of tumor resection was 93%. The patient showed transient transcortical aphasia and Gerstmann's syndrome after surgery but eventually recovered. The pathological diagnosis was anaplastic oligodendroglioma, and the patient was administered chemo-radiotherapy. The patient has been progression free for more than 2 years. The combination of subdural electrode mapping and monitoring during awake craniotomy is useful in order to achieve preservation of function and extensive resection for gliomas in the dominant parietal lobe.

TREATING GERSTMANN'S SYNDROME WITH NATALIZUMAB

Gerstmann9s syndrome is a rare disorder resulting from damage to the angular gyrus of the dominant parietal lobe leading to agraphia, acalculia, finger agnosia and left-right disorientation. In adults the syndrome is usually seen after stroke. Particularly in young patients other causes need to be considered. We present video, MRI and pathological evidence of the case of a 30 year old woman who developed Gerstmann9s syndrome as a result of a tumefactive multiple sclerosis (MS) lesion affecting the left cerebral hemisphere. Intravenous corticosteroids failed to stop rapid enlargement of the index lesion and occurrence of additional hemispheric lesions leading to clinical deterioration. Brain biopsy confirmed the diagnosis of MS. Strong contrast enhancement of the lesions prompted us to start treatment with natalizumab 300 mg i.v. every four weeks leading to sustained disease remission over a 14 month follow-up period though complex-focal epileptic seizures require ongoing anti-epileptic treatment. This case highlights the heterogeneous presentation of tumefactive MS, the need in some cases of an early brain biopsy, and the worthwhile consideration of natalizumab treatment where additional evidence supports a diagnosis of relapsing MS.

Editorial: Functional mapping

Direct cortical electrostimulation during brain surgery has been the basis of much of our understanding of functional regions of the cortex. The classic electrostimulation studies of Wilder Penfield and Herbert Jasper still guide our approaches to eloquent brain regions today. Direct cortical electrostimulation has also traditionally been the litmus test of whether neurological deficits would be incurred by tissue removal. This principle guides neurosurgeons removing lesions in the vicinity of languagebearing or sensorimotor cortex. It is also clear that removal of other known functional brain regions could result in specific neurological dysfunction (such as visual loss in occipital resection, alexia in dominant posterior temporal resection, and Gerstmann syndrome in dominant parietal lobe resection). The accompanying study by Della Puppa et al. documents an unexpected finding of mathematical processing dysfunction elicited by direct cortical electrostimulation of the nondominant parietal lobe, in the vicinity of the intraparietal sulcus.1 Data was obtained from 3 patients who were undergoing awake surgery of this area, and the authors found a reproducible dysfunction of multiplication and addition functions induced by direct cortical stimulation in the nondominant parietal lobe at relatively low amplitudes. These regions were spared and the patients had no deficit in mathematical processing postoperatively. Given that conventional wisdom holds that computational processing is housed in the dominant inferior parietal lobule, the results of this study contradict that widely held belief. Theirs is therefore an interesting and potentially important observation. It is not clear, however, that there is a 1-to-1 correlation between stimulation-induced function and focal deficit after resection. For example, the basal temporal lobe cortex on the dominant side commonly harbors language sites, yet resection of this area is routine in temporal lobe resections, and results in no detectable deficit. One must therefore interpret the results of the present study with caution. It must be remembered that mathematical processing—like many of the more complex brain functions—is likely a distributed function. The finding of a “node” in this network that could be stimulated and cause interruption in this function does not mean that this is the only such node, or even that it is a necessary one. Just like the basal temporal lobe and its relationship to language, it is possible that these areas in the nondominant parietal lobe could be safely resected despite the findings on direct cortical electrostimulation mapping. This study nicely illustrates a fairly highly localized area whose stimulation results in specific mathematical dysfunction. In order to improve our understanding of the significance of this finding, it should be followed up with focused functional MRI studies in an attempt to corroborate the significance of the direct cortical electrostimulation findings. Functional MRI could also help answer questions relating to the possibility of other brain regions involved in this function, and perhaps provide an answer to the question of where division and subtraction went. (http://thejns.org/doi/abs/10.3171/2013.4.JNS13560)

Clinical Progress of Gerstmann's Syndrome with Left Frontal Lobe Lesion: Two Cases

Gerstmann’s syndrome, assigned to a lesion of the dominant parietal lobe, is a neurological disorder characterized by acalculia, agraphia, right-left disorientation and finger agnosia. Some studies report that these symptoms are also shown in other brain lesions. We report two patients who presented with this tetrad of symptoms in initial assessment. Their Brain MRI images both showed lesion of left frontal lobe. Over time, these symptoms became better but some still remained in last assessment. Accordingly, we suggest that a left frontal lesion cause Gerstmann’s syndrome. Received: December 1, 2013 Revision received: December 12, 2013 Accepted: December 12, 2013

Right superior longitudinal fasciculus: Implications for visuospatial neglect mimicking Gerstmann's syndrome

Gerstmann’s syndrome comprises a tetrad of symptoms: finer agnosia, right–left disorientation, dysgraphia, and dyscalculia 1]. Although Gerstmann’s syndrome is described in textbooks as n example of damage to the dominant parietal lobe, the sympoms could be associated with visuospatial disturbances that are ommonly caused by lesions of the non-dominant parietal lobe nd its associated subcortical fiber tracts. The following case report llustrates that the symptoms of Gerstmann’s syndrome could be elated to a disturbance of the white matter association fiber netork in the non-dominant hemisphere, manifest as consequence f damages in superior longitudinal fasciculus (SLF) and inferior arietal cortex.

Gerstmann's Syndrome in Acute Stroke Patients

Objective:Gerstmann in 1924. observed in a few patients a concomitant impairment in discriminating their own fingers, writing by hand, distinguishing left from right and performing calculations. He claimed that this tetrad of symptoms constituted a syndromal entity, assigned it to a lesion of the dominant parietal lobe. Since than, Gerstmann`s syndrome (GS) was enigma for neuropsychologists. The aim of this study was to analyze frequency and clinical features of GS among acute stroke patients.Patients and methods:We prospectively analyzed 194 acute stroke patients (average age 65±11.06 years, male 113 (58.2%), female 81 (41.8%) hospitalized at department of Neurology, University Clinical Center tuzla, during the six mounths in 2010. For clinical assessment of agraphia, alexia and acalculia we used Minessota test for differential diagnosis of aphasia’s.Results:Among these acute stroke patients, 59 (30.40%) had alexia, agraphia and acalculia or different combinations of these disorders. two patients (3.4%) had agraphia and acalculia associated with other part of tetrad of GS: fi nger agnosia and left-right disorientation. they both where men, right handed, and cranial computed tomography scan showed ischemic lesion in the left parietal and left temporoparietal lobe.Conclusion:Gerstmann`s syndrome is rare clinical entity, and has the high value in localization and the lesion is mainly localized to angular gyrus of the dominant hemisphere.

The enigma of Gerstmann's syndrome revisited: a telling tale of the vicissitudes of neuropsychology

Eighty years ago, the Austrian neurologist Josef Gerstmann observed in a few patients a concomitant impairment in discriminating their own fingers, writing by hand, distinguishing left from right and performing calculations. He claimed that this tetrad of symptoms constituted a syndromal entity, assigned it to a lesion of the dominant parietal lobe and suggested that it was due to damage of a common functional denominator. Ever since, these claims have been debated and an astute synopsis and sceptical discussion was presented 40 years ago by MacDonald Critchley in this journal. Nonetheless, Gerstmann's syndrome has continued to intrigue both clinical neurologists and researchers in neuropsychology, and more frequently than not is described in textbooks as an example of parietal lobe damage. In this review, we revisit the chequered history of this syndrome, which can be seen as a case study of the dialectic evolution of concepts in neuropsychology. In light of several modern era findings of pure cases we conclude that it is legitimate to label the conjunction of symptoms first described by Gerstmann as a 'syndrome', but that it is very unlikely that damage to the same population of cortical neurons should account for all of the four symptoms. Instead, we propose that a pure form of Gerstmann's syndrome might arise from disconnection, via a lesion, to separate but co-localized fibre tracts in the subcortical parietal white matter, a hypothesis for which we have recently provided evidence using combined imaging of functional and structural organization in the healthy brain.