[Show abstract][Hide abstract] ABSTRACT: OBJECT Acute cervical spine injuries have been extensively studied in high-level contact sports. However, the relation between the appearance of degenerative cervical spine disease and the exposure to repeated trauma in such sports as rugby is still unclear. Using clinical and MRI evaluation, we aimed to determine if former professional rugby players had more serious degenerative cervical spine symptoms than the general population. METHODS Two groups, one composed of 101 former rugby players (all men, mean age 40.3 years, range 35-47 years, SD 2.3 years) and the other of 85 male volunteers serving as a control group (mean age 41.6 years, range 35-49 years, SD 4.5 years) were studied. The former rugby players were evaluated on average 5.8 years after retirement (range 1-16 years, SD 3.5 years). The groups were matched in terms of sex, age, job, current sports training, and smoking habits. Each participant received a complete neurological evaluation. Clinical symptoms were evaluated using the Japanese Orthopaedic Association (JOA) questionnaire, and chronic neck pain was specifically evaluated using a visual analog scale (VAS) and the Neck Disability Index (NDI). Overall, 25 MRI studies were performed in each group. MRI studies, including dynamic sequences, focused on degenerative lesions (Matsumoto score and canal diameter) and on muscular and medullary morphological analysis. RESULTS Significantly more former rugby players than controls complained of chronic neck pain (51 [50.50%] of 101 vs 27 [31.76%] of 85, p = 0.01). Rugby players also had significant reductions of neck mobility. Nevertheless, in those complaining of pain, there was no statistically significant difference between groups with respect to VAS and NDI scores (p = 0.57). On MRI, former rugby players had a narrower vertebral canal (on average 0.88 ± 0.167 cm vs 0.99 ± 0.130 cm, p = 0.007) and more foraminal stenosis (p = 0.01). No significant difference in the Matsumoto score was found between the 2 groups with respect to other degenerative lesions. Former rugby players had more often undergone surgery for a degenerative condition than had members of the control group (10 cases vs 0 in the control group, p = 0.0021). CONCLUSIONS A few years after retirement, former professional rugby players seem to have more frequent cervical spine pain and MRI degenerative lesions, such as foraminal stenosis and narrowing of the spinal canal, compared with controls who had not been professional rugby players. A longer evaluation is necessary to determine if these findings persist over time.
[Show abstract][Hide abstract] ABSTRACT: Object
Sparing optic radiations can be of paramount importance during epilepsy surgery of the temporal lobe. The anatomical heterogeneity of the Meyer’s loop of the optic radiations could be assessed by means of diffusion tensor tractography. We used temporal lobe surgery as a lesion model to validate this method.
Material and methods
We analyzed the distance between the temporal pole (TP) and Meyer’s loop (ML) and the correlation between visual impairment and the percentage of virtual fibers injured. MRI studies were performed in 18 patients and 13 controls. Diffusion tensor imaging (DTI) with fiber tracking was performed using four different algorithms and various gradient directions (15 or 32) and fractional anisotropy (FA) thresholds (0.18, 0.20, and 0.22). To find the best DTI model, we tested each gradient direction and FA threshold on 16 operated patients by pre- and post-operative visual field testing that analyzed the percentage of virtual fibers damaged on 3-month-post-operative MRIs.
Marked individual differences were noted in the TP-ML distances (mean: 25.4 mm; range 18.2–38.3 mm; standard deviation: 4.7) but with no significant difference between patients and controls (P = 0.9). The percentage of virtual fibers reconstructed by tracking and damaged by surgery was correlated with visual impairment. Significant differences appeared between algorithm types. The tensor-line algorithm with 15-direction resolution and an anisotropy threshold of 0.18 seemed to be the most relevant. A threshold of 5.5% of injured virtual fiber could predict a visual defect with a sensitivity of 71.4% and a specificity of 87.5%.
Optic radiation tractography by DTI could be a useful method to assess an individual patient’s risk of postoperative visual deficit.
No preview · Article · Jul 2014 · Clinical Neurology and Neurosurgery
[Show abstract][Hide abstract] ABSTRACT: Cortical electrical stimulation mapping was used to study neural substrates of the function of writing in the temporoparietal cortex. We identified the sites involved in oral language (sentence reading and naming) and writing from dictation, in order to spare these areas during removal of brain tumours in 30 patients (23 in the left, and 7 in the right hemisphere). Electrostimulation of the cortex impaired writing ability in 62 restricted cortical areas (.25 cm(2)). These were found in left temporoparietal lobes and were mostly located along the superior temporal gyrus (Brodmann's areas 22 and 42). Stimulation of right temporoparietal lobes in right-handed patients produced no writing impairments. However there was a high variability of location between individuals. Stimulation resulted in combined symptoms (affecting oral language and writing) in fourteen patients, whereas in eight other patients, stimulation-induced pure agraphia symptoms with no oral language disturbance in twelve of the identified areas. Each detected area affected writing in a different way. We detected the various different stages of the auditory-to-motor pathway of writing from dictation: either through comprehension of the dictated sentences (word deafness areas), lexico-semantic retrieval, or phonologic processing. In group analysis, barycentres of all different types of writing interferences reveal a hierarchical functional organization along the superior temporal gyrus from initial word recognition to lexico-semantic and phonologic processes along the ventral and the dorsal comprehension pathways, supporting the previously described auditory-to-motor process. The left posterior Sylvian region supports different aspects of writing function that are extremely specialized and localized, sometimes being segregated in a way that could account for the occurrence of pure agraphia that has long-been described in cases of damage to this region.
[Show abstract][Hide abstract] ABSTRACT: Considered as the most famous French military surgeon, Dominique-Jean Larrey (1766-1842), who joined all the campaigns of Napoleon, wrote his memoirs and several medical articles. This paper discusses how in the Napoleonic times, Larrey dealt with neurosurgical diseases or injuries.
We reviewed four main publications of Larrey published between 1812 and 1838 and analyzed the type of neurosurgical cases presented and their treatment.
These works include his practice of what we call now "neurosurgery" since most injuries described concern the skull or spine. He seemed to treat patients with humanity, integrity and perseverance. Larrey dealt with many aspects of neurosurgery, such as cranial or spinal trauma surgery, and also infectious diseases. He saw many head injuries inflicted not only by muskets or artillery, but also with spears and sabers. Unlike some others, Larrey advocated the use of trepanation in many situations as practiced, for instance, in the treatment of depressed fractures or in presence of subdural collections. On the other hand, this surgeon who saw thousands of amputees during his career did not mention the phantom limb phenomenon in his memoirs. Similarly, the issue of cerebral localizations is only mentioned in his last work, published in 1838.
In his work, Larrey (and all his contemporaries) dealt essentially with "cranial" surgery, as in skull fractures where the brain could potentially have been injured by bone fragments. The time for brain surgery had not come yet.
No preview · Article · Sep 2013 · Clinical neurology and neurosurgery
[Show abstract][Hide abstract] ABSTRACT: Handwriting is a modality of language production whose cerebral substrates remain poorly known although the existence of specific regions is postulated. The description of brain damaged patients with agraphia and, more recently, several neuroimaging studies suggest the involvement of different brain regions. However, results vary with the methodological choices made and may not always discriminate between "writing-specific" and motor or linguistic processes shared with other abilities.
We used the "Activation Likelihood Estimate" (ALE) meta-analytical method to identify the cerebral network of areas commonly activated during handwriting in 18 neuroimaging studies published in the literature. Included contrasts were also classified according to the control tasks used, whether non-specific motor/output-control or linguistic/input-control. These data were included in two secondary meta-analyses in order to reveal the functional role of the different areas of this network.
An extensive, mainly left-hemisphere network of 12 cortical and sub-cortical areas was obtained; three of which were considered as primarily writing-specific (left superior frontal sulcus/middle frontal gyrus area, left intraparietal sulcus/superior parietal area, right cerebellum) while others related rather to non-specific motor (primary motor and sensorimotor cortex, supplementary motor area, thalamus and putamen) or linguistic processes (ventral premotor cortex, posterior/inferior temporal cortex).
This meta-analysis provides a description of the cerebral network of handwriting as revealed by various types of neuroimaging experiments and confirms the crucial involvement of the left frontal and superior parietal regions. These findings provide new insights into cognitive processes involved in handwriting and their cerebral substrates.
[Show abstract][Hide abstract] ABSTRACT: A fundamental issue in cognitive neuroscience is the existence of two major, sub-lexical and lexical, reading processes and their possible segregation in the left posterior perisylvian cortex. Using cortical electrostimulation mapping, we identified the cortical areas involved on reading either orthographically irregular words (lexical, "direct" process) or pronounceable pseudowords (sublexical, "indirect" process) in 14 right-handed neurosurgical patients while video-recording behavioral effects. Intraoperative neuronavigation system and Montreal Neurological Institute (MNI) stereotactic coordinates were used to identify the localization of stimulation sites. Fifty-one reading interference areas were found that affected either words (14 areas), or pseudo-words (11 areas), or both (26 areas). Forty-one (80%) corresponded to the impairment of the phonological level of reading processes. Reading processes involved discrete, highly localized perisylvian cortical areas with individual variability. MNI coordinates throughout the group exhibited a clear segregation according to the tested reading route; specific pseudo-word reading interferences were concentrated in a restricted inferior and anterior subpart of the left supramarginal gyrus (barycentre x = -68.1; y = -25.9; z = 30.2; Brodmann's area 40) while specific word reading areas were located almost exclusively alongside the left superior temporal gyrus. Although half of the reading interferences found were nonspecific, the finding of specific lexical or sublexical interferences is new evidence that lexical and sublexical processes of reading could be partially supported by distinct cortical sub-regions despite their anatomical proximity. These data are in line with many brain activation studies that showed that left superior temporal and inferior parietal regions had a crucial role respectively in word and pseudoword reading and were core regions for dyslexia.
[Show abstract][Hide abstract] ABSTRACT: Cortical and subcortical electrostimulation mapping during awake brain surgery for tumor removal is usually used to minimize deficits.
To use electrostimulation to study neuronal substrates involved in spatial awareness in humans.
Spatial neglect was studied using a line bisection task in combination with electrostimulation mapping of the right hemisphere in 50 cases. Stimulation sites were identified with Talairach coordinates. The behavioral effects induced by stimulation, especially eye movements and deviations from the median, were quantified and compared with preoperative data and a control group.
Composite and highly individualized spatial neglect maps were generated. Both rightward and leftward deviations were induced, sometimes in the same patient but for different stimulation sites. Group analysis showed that specific and reproducible line deviations were induced by stimulation of discrete cortical areas located in the posterior part of the right superior and middle temporal gyri, inferior parietal lobe, and inferior postcentral and inferior frontal gyri (P < .05). Fiber tracking identified stimulated subcortical areas important to spare as sections of fronto-occipital and superior longitudinal II fascicles. According to preoperative and postoperative neglect battery tests, the specificity and sensitivity of intraoperative line bisection tests were 94% and 83%, respectively.
In humans, discrete cortical areas that are variable in location between individuals but mainly located within the right posterior Sylvian fissure sustain visuospatial attention specifically toward the contralateral or ipsilateral space direction. Line bisection mapping was found to be a reliable method for minimizing spatial neglect caused by brain tumor surgery.
[Show abstract][Hide abstract] ABSTRACT: The use of an awake craniotomy in the treatment of supratentorial lesions is a challenge for both patients and staff in the operation theater.
To assess the safety and effectiveness of an awake craniotomy with brain mapping in comparison with a craniotomy performed under general anesthesia.
We prospectively compared 2 groups of patients who underwent surgery for supratentorial lesions: those in whom an awake craniotomy with intraoperative brain mapping was used (AC group, n = 214) and those in whom surgery was performed under general anesthesia (GA group, n = 361, including 72 patients with lesions in eloquent areas). The AC group included lesions in close proximity to the eloquent cortex that were surgically treated on an elective basis.
Globally, the 2 groups were comparable in terms of sex, age, American Society of Anesthesiologists score, pathology, size of lesions, quality of resection, duration of surgery, and neurological outcome, and different in tumor location and preoperative neurological deficits (higher in the AC group). However, specific data analysis of patients with lesions in eloquent areas revealed a significantly better neurological outcome and quality of resection (P < .001) in the AC group than the subgroup of GA patients with lesions in eloquent areas. Surgery was uneventful in AC patients and they were discharged home sooner.
AC with brain mapping is safe and allows maximal removal of lesions close to functional areas with low neurological complication rates. It provides an excellent alternative to craniotomy under GA.
[Show abstract][Hide abstract] ABSTRACT: Direct cortical electrostimulation was used to study cortical areas hypothetically involved in translation in bilinguals during brain tumour resections, with a view to sparing these functional areas. A series of seven proficient bilingual patients was studied: two left-handed and five right-handed individuals with no pre-existing language deficit. Hemispheric cortex (on the side contralateral to the patient's hand-dominance) was directly stimulated whilst the patient performed naming and reading tasks in both languages and a translation task (of a written text from their second 'learned' language to their first or 'native' language). Of the 147 different cortical sites studied, 26 'language functional sites' were detected, where electrostimulation affected reading and/or naming in the patient's native and/or second learned language. Of these, 8 sites (in 4 patients) were "task-specific" and "language-specific" i.e., affecting only naming or reading in only one of the patient's languages. Of the 26 "language sites", only 3 produced any interferences in translation. All of these were located in frontal regions. Electrostimulation at these sites caused the patient to stop translating abruptly, but no language switching or other translation-related phenomenon was observed. No site was found that was involved only in translation and not other language tasks. Overall, in contrast to other language tasks, cortical structures of the convexity were rarely involved in translation. We suggest that translation interference could be more readily detected by subcortical stimulations. This spatial dissociation within the brain of translation function versus other language functions could explain the cases of dissociated language impairments observed in some bilingual patients with brain lesions. On a practical level, because the cortical sites found by translation tasks are few and related with other cortical language sites, we think that translation tasks provide little additional helpful information for cortical brain mapping in bilingual neurosurgical patients.
[Show abstract][Hide abstract] ABSTRACT: Selective naming categories impairments for living and non-living things are widely reported in brain damaged patients. Electrostimulation mapping was used to study the possible anatomical segregation of living/non-living categories in a prospective series of patients operated on for tumor removal.
Fifty brain mappings (patients with no language impairment; range: 14-80 years; mean: 48 years; 26 males; 5 left handed) were performed in 46 left and 4 right hemispheres using two linguistically controlled tasks (naming for living and non-living things) during an awake surgery procedure. Fifteen regions and four macro cortical areas were designed to analyze the distribution of the interference sites.
Over 761 sites stimulated in the lateral hemispheres, 130 naming interferences sites were detected in small cortical areas (<1cm(2)). High individual variability was observed for living/non-living word retrieval localization and organization with a majority (62%) of shared living/non-living interferences. Specific living (12%) or non-living (26%) interferences were found too. In group analysis, no statistical significant anatomical localization was observed for living items in left lateral hemispheric cortex. A statistical significant representation of interference sites for non-living objects was found (Generalized Estimating Equation methodology, z-test=2.28, p=0.027) in the left posterolateral temporoparietal cortex. No influence of histopathology, gender and age on anatomical localization of naming categories was detected.
The existence of dedicated neural structures for naming non-living things in the left posterolateral temporoparietal cortex is supported by this study although high individual differences exist in the organization of word categories retrieval.
[Show abstract][Hide abstract] ABSTRACT: Frontoethmoidal mengingoencephaloceles (fMECs) are frequently observed in Cambodia, especially in poor families. The authors describe issues related to the surgical treatment of fMECs in Cambodia at the end of a humanitarian program that provided surgery free of charge to patients and their families.
The authors reviewed 257 cases of fMEC involving patients who presented to their institution, the Children's Surgical Center in Phnom Penh, between 2004 and 2009. They treated 200 of these patients surgically (108 males, 92 females; 89% younger than 18 years) using a "low-cost" management plan with no routine pre- or postoperative investigations. Initially, surgery was performed by visiting foreign surgeons who taught the procedures to resident surgeons. Patients were not charged for consultations or treatment and received at least 1 follow-up examination 6 months postoperatively.
The nasoethmoidal type was the most frequent fMEC encountered (69%). Many patients had associated ophthalmological issues (46% of cases). Only 1 familial case was detected. Combined neurosurgical and facial procedures were successfully standardized and learned by surgeons initially unfamiliar with fMEC management. A neurosurgical approach avoided the need for a facial incision in 42 cases, improving cosmetic results. The most common postoperative issues were a temporary CSF leak (24 cases [12%]) and/or infection (28 cases [14%]). There were 3 deaths directly related to the operations. Cosmetic results were good in 145 cases, average in 27, poor in 7, and worse than preoperative appearance in 6 patients. Fifteen patients were lost to follow-up. The parents of 87% of the children were rice farmers. Questionnaire results confirmed that fMEC has important social and educational consequences for the affected children and that these consequences can be partially improved by fMEC correction.
This experience in fMEC management demonstrates that local surgeons can treat these malformations with limited surgical materials and in a nonspecialized infrastructure after principles of treatment have been learned and if they are carefully respected. Surgery for fMEC can thus be more accessible to a larger number of patients in developing countries. Moreover, local treatment facilitates better postoperative and follow-up care.
Full-text · Article · Dec 2010 · Journal of Neurosurgery Pediatrics
[Show abstract][Hide abstract] ABSTRACT: Surgical resection of mass lesions in Broca's area is controversial. To demonstrate that pathology may influence the localization of functional areas and language performance, we reviewed our experience of awake craniotomies in Broca's area.
Sixteen consecutive patients who underwent awake craniotomy and direct brain mapping for resective surgery in Broca's area were analyzed. Six patients had well-circumscribed lesions, whereas 10 patients had infiltrative gliomas. A short version of the Boston Diagnostic Aphasia Examination test was used for language assessment.
Inferior frontal language sites were found in all but 4 patients. In patients with cavernomas or well-circumscribed tumors, 9 of 9 (100%) of the positive sites were located in the classic Broca's area (BA 44/45). By contrast, in those patients with gliomas, only 5 of 20 (25%) of the positive sites were located in BA 44/45. Patients with infiltrative gliomas demonstrated more deficits in the pre and postoperative periods than those with well-circumscribed mass lesions. All patients returned to their baseline abilities within 6 months.
Intraoperative language maps generated in cases with well-circumscribed lesions are different from those generated in cases with infiltrative gliomas. This supports the view that interindividual language variability and displacement of critical structures by mass effect should first be considered for circumscribed lesions, whereas reshaping should largely be attributed to brain plasticity in gliomas. Surgery in Broca's area can be safely conducted using awake craniotomy and brain mapping.
[Show abstract][Hide abstract] ABSTRACT: We have translated the most famous text of Sigmund Exner (1846-1926), which relates to the existence of a localised "writing centre" in the brain. We discuss its relevance to modern studies and understanding of writing and agraphia. In Exner's most famous text, he hypothesised about the eponymous "Exner's Area", a discrete area within the brain that was located in the left middle frontal gyrus, which was dedicated to the function of writing. This text in German, included in a book published in 1881 "Untersuchungen über die Lokalisation der Functionen in der Grosshirnrinde des Menschen" (Studies on the localisation of functions in the cerebral cortex of humans), lent itself to passionate debates during the following decades on the possibility of finding a specific writing centre in left middle frontal gyrus. Modern authors still refer back to the evidence cited in this seminal text. However, over the 281 pages of Exner's book, only a few chapters dealt with agraphia. Only four of the 167 case reports in the book explicitly mention agraphia. Although Exner describes the anatomical details of these lesions (from autopsies), no patient had pure agraphia, and only one case had an isolated lesion of the posterior part of the middle frontal gyrus. The small number of patients, the absence of pure agraphia symptoms, and the variation in the anatomy of these lesions are the main reasons why Exner's hypothesis of a writing centre in left middle frontal gyrus has been continually debated until now. More than the seminal publication of Sigmund Exner on agraphia, we think that the diffusion of his hypothesis was partly due to the influence that Exner and his family had within the scientific community at the turn of the 20th century.
[Show abstract][Hide abstract] ABSTRACT: Although endoscopic third ventriculostomy (ETV) has been accepted as a procedure of choice for the treatment of obstructive hydrocephalus, the outcome of this treatment remains controversial with regard to age, cause, and long-term follow-up results. The goal of this study was to assess the risk of failure associated with these factors in a retrospective cohort study.
Between 1999 and 2007, 368 ETVs were performed in 350 patients (165 patients < 18 years of age) with hydrocephalus at the University Hospital of Toulouse. Failure of ETV was defined as cases requiring any subsequent surgical procedure for CSF diversion or death related to hydrocephalus management.
Tumors (53%), primary aqueductal stenosis (18%), and intracranial hemorrhage (13%) were the most common causes of hydrocephalus. The median follow-up period was 47 months (range 6-106 months), and the overall success rate was 68.5% (252 of the 368 procedures). Patients < 6 months of age had a 5-fold increased risk of ETV failure than older patients (adjusted hazard ratio [HRa] 5.0; 95% CI 2.4-10.4; p < 0.001). Hemorrhage-related (HRa 4.0; 95% CI 1.9-8.5; p < 0.001) and idiopathic chronic hydrocephalus (HRa 6.3, 95% CI 2.5-15.0, p < 0.001) had a higher risk of failure than other causes. Most failures (97%) occurred within 2 months of the initial procedure. The overall morbidity rate was 10%, although most complications were minor. Finally, the introduction of ETV in the authors' department reduced the number of shunt insertions and hospital admissions for shunt failures by half and was a source of cost savings.
Endoscopic third ventriculostomy is a safe procedure and an effective treatment option for hydrocephalus. Factors indicating potential poor ETV outcome seem to be very young children and hemorrhage-related and chronic hydrocephalus in adults.
Preview · Article · Jan 2010 · Journal of Neurosurgery Pediatrics
[Show abstract][Hide abstract] ABSTRACT: Cervical spine injuries after diving into private swimming pools can lead to dramatic consequences. We reviewed 34 patients hospitalized in our center between 1996 and 2006. Data was collected from their initial admission and from follow-up appointments. The injuries were sustained by young men in 97% (mean age 27) and the majority happened during the summer (88%). Fractures were at C5-C7 in 70%. American Spinal Injury Association class (ASIA) on admission was A for 8 patients, B for 4, C for 4, D for 1, and E for 17. There were 23 surgical spine stabilizations. Final ASIA class was A for 6 patients, B for 1, C for 3, D for 5, and E for 18. The mean duration of hospitalization was 21.3 days in our neurosurgical center (mean overall cost: 36,000 Euros/patient) plus 10.6 months in rehabilitation center for the 15 patients admitted who had an ASIA class A to C. Mean overall direct cost for a patient with class A is almost 300,000 Euros, compared to around 10,000 Euros for patients with class D and E. In addition, a profound impact on personal and professional life was seen in many cases including 11 divorces and 7 job losses. Dangerous diving into swimming pools can result in spinal injuries with drastic consequences, including permanent physical disability and a profound impact on socio-professional status. Moreover, there are significant financial costs to society. Better prevention strategies should be implemented to reduce the impact of this public health problem.
Preview · Article · Dec 2009 · European Spine Journal
[Show abstract][Hide abstract] ABSTRACT: Frontoethmoidal meningoencephalocele (fMEC) is relatively common in many Southeast Asian countries, with devastating aesthetic and social consequences for affected children. No cause has been detected to date. Among other factors, the authors of this paper attempt to identify a statistically significant difference in the spread of fMEC births throughout the year compared with other births. This seasonal variation in the incidence of fMEC births may provide clues to the causes of this condition.
From a group of 175 children with fMEC who underwent surgery at the authors' humanitarian institution (Children's Surgical Centre) in Phnom Penh between 2004 and 2008, 86 children were studied. These children were born at full term and had an accurately recorded date of birth. The birth dates of this fMEC group were compared with a group of > 15,000 other live births at one of the main maternity units in Phnom Penh in 2005 and 2006.
Seasonal variation in incidence of fMEC by month of birth was highly statistically significant (p < 0.001), with the peak of births occurring in the dry season (between March and May). This is in contrast to the control group, in which there was an equal distribution of births throughout the year. More than 85% of the parents of children with fMEC who the authors treated were farmers, but this figure reflects the composition of the Cambodian population.
Uneven spread in the incidence of fMEC births throughout the year suggests that a seasonal factor during the wet season may be suspected in the pathogenesis of fMEC in Cambodia.
No preview · Article · Dec 2009 · Journal of Neurosurgery Pediatrics
[Show abstract][Hide abstract] ABSTRACT: In 1881, Exner first described a "graphic motor image center" in the middle frontal gyrus. Current psycholinguistic models of handwriting involve the conversion of abstract, orthographic representations into motor representations before a sequence of appropriate hand movements is produced. Direct cortical stimulation and functional magnetic resonance imaging (fMRI) were used to study the human frontal areas involved in writing.
Cortical electrical stimulation mapping was used intraoperatively in 12 patients during the removal of brain tumors to identify the areas involved in oral language (sentence reading and naming) and writing, and to spare them during surgery. The fMRI activation experiment involved 12 right-handed and 12 left-handed healthy volunteers using word dictation (without visual control) and 2 control tasks.
Direct cortical electrical stimulation of restricted areas rostral to the primary motor hand area (Brodmann area [BA] 6) impaired handwriting in 6 patients, without disturbing hand movements or oral language tasks. In 6 other patients, stimulation of lower frontal regions showed deficits combining handwriting with other language tasks. fMRI also revealed selective activation during word handwriting in left versus right BA6 depending on handedness. This area was anatomically matched to those areas that affected handwriting on electrical stimulation.
An area in middle frontal gyrus (BA6) that we have termed the graphemic/motor frontal area supports bridging between orthography and motor programs specific to handwriting.
Full-text · Article · Oct 2009 · Annals of Neurology