Keith G. Davies

Naming Decline After Left Anterior Temporal Lobectomy Correlates with Pathological Status of Resected Hippocampus

Summary: Purpose: To evaluate the determinants of postoperative change in visual confrontation naming ability and the differential sensitivity of two common tests of confrontation naming.

The interictal dysphoric disorder: recognition, pathogenesis, and treatment of the major psychiatric disorder of epilepsy

The unawareness of psychiatrists about the importance of epilepsy dates back half a century, when epilepsy became considered an ordinary neurologic disorder. Epileptic seizures, however, can be provoked in every human being. Epilepsy is an extraordinary disorder that, beyond its well-known neurologic complexities, tends to become complicated with a wide range of specific psychiatric changes; they occur on the establishment of a temporal-limbic focus of intermittent excessive neuronal excitatory activity that produces increasingly inhibitory responses. These changes are distinct from those related to the two major psychiatric spheres for which a genetic basis is established, i.e., the manic-depressive and schizophrenic disorders, and represent a genetic sphere of its own. Apart from more subtle personality changes and the serious late complications of interictal psychoses and suicidal episodes, the key psychiatric syndrome associated with epilepsy consists of the interictal dysphoric disorder, with its characteristic intermittent and pleomorphic symptomatology. This disorder was clearly identified about a century ago by Kraepelin, when he established a comprehensive basis for the modern classification of the psychiatric disorders, at a time when epilepsy represented an area of major interest to psychiatrists. A practical method of recognizing the dysphoric disorder is reported. The disorder tends to be very treatable by combining psychotropic (chiefly antidepressant) with antiepileptic medication. The variations in treatment approach required are discussed and illustrated by representative case studies. Psychiatrists must become familiar with the psychiatric aspects of epilepsy to be able to assist the neurologists who focus on the neural complexities of the illness. They also must become able to recognize, among their own patients, the presence of a subictal dysphoric disorder that requires the same treatment as the interictal dysphoric disorder; combined treatment with antidepressant and antiepileptic medication is likewise indicated for the premenstrual dysphoric disorder, a condition that appears to belong to the spectrum of epilepsy-related psychiatric disorders. Furthermore, they must learn how an ignored population in their care, epilepsy patients confined to state hospitals, can be properly treated. Of particular importance is the need for psychiatrists to become familiar with the role of the paroxysmal affects in the general human condition, with their basic conflict to be intermittently angry and irascible yet otherwise good-natured, helpful, and religious--a conflict that tends to be particularly accentuated among patients with the Sacred Disease.

Assessment of the variability in the anatomical position and size of the subthalamic nucleus among patients with advanced Parkinson’s disease using magnetic resonance imaging

PurposeTargeting of the subthalamic nucleus (STN) during deep brain stimulation (DBS) surgery using standard atlas coordinates is used in some centers. Such coordinates are accurate for only a subgroup of patients, and subgroup size depends on the extent of inter-individual variation in STN position/size and degree to which atlas represents average anatomical relations. Few studies have addressed this issue.MethodsSixty-two axial T2-weighted magnetic resonance (MR) images of the brain (1.5 T) were obtained before STN-DBS in 62 patients (37 males) with Parkinson’s disease using a protocol optimized for STN visualization. Image distortion was within sub-millimeter range. Midcommissural point (MCP)-derived coordinates of STN borders, STN center, and other brain landmarks were obtained using stereotactic software. MR-derived measurements were compared to Schaltenbrand and Wahren Atlas.ResultsWe evaluated 117 best-visualized STNs. STN dimensions and coordinates of its center were highly variable. STN lateral coordinate ranged 8.7xa0mm–14.5xa0mm from MCP, A-P coordinate 3.5xa0mm posterior to 0.5xa0mm anterior to MCP, and vertical coordinate 1.3xa0mm–6xa0mm below MCP. The antero-posterior nucleus dimension varied by 8xa0mm and lateral-medial dimension by 5.8xa0mm. Differences between mean values of MR-derived data sets and Atlas values were statistically significant but moderate, excluding AC-PC length, for which the Atlas value was below the 1st percentile of the MR data set. The STN lateral coordinate strongly correlated with the width of the third ventricle (ru2009=u20090.73, pu2009<u20090.001).ConclusionsIt is now possible to directly evaluate STNs at 1.5 T with minimal image distortion, which reveals variation in STN position and dimensions in the range of nucleus size. This puts under question the rationale of use of standard STN coordinates during DBS surgery.

Naming ability after tailored left temporal resection with extraoperative language mapping: Increased risk of decline with later epilepsy onset age

Standard temporal resection in the left hemisphere carries the risk of postoperative naming ability decline, especially with later epilepsy onset age/absence of hippocampal sclerosis. Language mapping has been performed routinely at some centers to minimize postoperative primary language impairment, but its effect on changes in naming performance has not been explored. This study examined naming outcome in 24 patients with nonlesional epilepsy who had left temporal resection after extraoperative language mapping. The mean decline in Boston Naming Test (BNT) score was 7.8, and 13 (54%) patients had a BNT decline greater than the Reliable Change Index. Simple correlations found significant relationships between BNT score decline and: later onset age, higher preoperative BNT score, and resection of isolated language sites. A multiple regression analysis showed that onset age was the best predictor of BNT decline. Although naming ability in patients with early onset age is stable with language mapping, there is still a risk of decline for those with later onset age.

Major Psychiatric Disorders Subsequent to Treating Epilepsy by Vagus Nerve Stimulation

Purpose. The goal of this work was documentation of incidence, phenomenology, pathogenesis, and treatment of psychiatric disorders occurring subsequent to treating epilepsy by vagus nerve stimulation (VNS).Methods. In a series of 81 patients treated by VNS, all patients who developed major psychiatric complications underwent systematic psychiatric evaluation and treatment with psychotropic medication; VNS was modified if necessary.Results. After the seizure frequency was reduced by at least 75%, 7 of 81 patients (9%) developed major psychiatric disorders: Six became severely dysphoric (5 with catastrophic rage and 4 with psychotic symptoms), and one became psychotic. All 7 patients had experienced dysphoric disorders and 2 had experienced psychotic episodes prior to the VNS treatment. Five patients had frequent daily seizures prior to treatment. Remission or satisfactory improvement was achieved with psychotropic medication in 6 patients, aided by decreasing or interrupting VNS in two patients. One patient was noncompliant and suffered a fatal outcome.Conclusion. Severe interictal dysphoric disorders associated with catastrophic rage and psychotic episodes may develop on suppressing seizures by VNS in patients with previous epilepsy-related psychiatric disorders. Patients with multiple daily seizures may be more vulnerable to this occurrence. The phenomenon corresponds to the common finding of interictal dysphoric and psychotic symptoms emerging when inhibitory mechanisms predominate (alternative psychiatric disorders in the absence of seizures, or forced normalization of the EEG). The dysphoric symptom of catastrophic rage appears to occur more often on seizure suppression by VNS than by antiepileptic drugs. Psychiatric intervention, primarily with antidepressant medication, must be available to secure a good outcome; decrease of VNS may occasionally be required.

Pleomorphic xanthoastrocytoma-report of four cases, with MRI scan appearances and literature review

Pleomorphic xanthoastrocytoma (PXA) is a rare glial tumour typically occurring in young patients in the first three decades, having a superficial cortical location and with a relatively good prognosis for long-term survival. Four cases are reviewed. The magnetic resonance imaging (MRI) appearances, which in PXA have been reported only once before, are described in three cases. The fourth case was studied by computed tomography and angiography. One patient developed seizures at age 2 days and was aged 2 1/2 years at presentation. This is the youngest patient with PXA yet reported. Three of the four patients had seizures, but in one case the tumour was not the cause of the seizures. Review of the literature has revealed 47 reported cases. Mean age at presentation was 14.3 years. Epilepsy occurred in 78%. Seventeen patients were alive without recurrence at a mean of 7.9 years after diagnosis and 10 patients died at a mean of 7.4 years after diagnosis. Thirteen cases had recurrence at a mean of 6 years after surgery and in five instances the recurrence was in the form of a glioblastoma. Resections which were grossly total were less likely to develop recurrence than those which were subtotal. Complete gross resection of tumour offers the best therapeutic option in PXA.

Isolation of the brain-related factor of the error between intended and achieved position of deep brain stimulation electrodes implanted into the subthalamic nucleus for the treatment of Parkinson's disease.

OBJECTIVE Although a few studies have quantified errors in the implantation of deep brain stimulation electrodes into the subthalamic nucleus (STN), a significant trend in error direction has not been reported. We have previously found that an error in axial plane, which is of most concern because it cannot be compensated for during deep brain stimulation programming, had a posteromedial trend. We hypothesized that this trend results from a predominance of a directionally oriented error factor of brain origin. Accordingly, elimination of nonbrain (technical) error factors could augment this trend. Thus, implantation accuracy could be improved by anterolateral compensation during target planning. METHODS Surgical technique was revised to minimize technical error factors. During 22 implantations, targets were selected on axial magnetic resonance imaging scans up to 1.5 mm anterolateral from the STN center. Using fusion of postoperative computed tomographic and preoperative magnetic resonance imaging scans, implantation errors in the axial plane were obtained and compared with distances from the lead to the STN to evaluate the benefit of anterolateral compensation. RESULTS Twenty errors and the mean error had a posteromedial direction. The average distances from the lead to the target and to the STN were 1.7 mm (range, 0.8–3.1 mm) and 1.1 mm (range, 0.1–1.9 mm), respectively. The difference between the 2 distances was significant (paired t test, P < 0.0001). The lower parts of the lead were consistently bent in the posteromedial direction on postoperative scout computed tomographic scans, suggesting that a brain-related factor is responsible for the reported error. CONCLUSION Elimination of the technical factors of error during STN deep brain stimulation implantation can result in a consistent posteromedial error. Implantation accuracy may be improved by compensation for this error in advance.

Intractable hiccups resolved after resection of a cavernous malformation of the medulla oblongata

Hiccups are reflexive involuntary contractions of the respiatory muscles followed very early by sudden closure of the lottis. While common in the fetal stages of life they are usually enign, short-lived, self-limited and very commonly overlooked in dults. Rarely, hiccups can indicate significant neurologic disease 1]. Here, we present a case of a patient presenting with 3 years f intractable hiccups and a single medullary cavernous malforation whose symptoms resolved after resection of the lesion. We hen discuss the available literature for medullary cavernomas preenting with hiccups and how surgical resection relieves symptoms ikely by compromising the vagal activity.

Optimal Stimulation Site

Object. The subthalamic nucleus (STN) is currently recognized as the preferred target for deep brain stimulation (DBS) in patients with Parkinson disease (PD). If there is agreement in the literature that DBS improves motor symptoms significantly, the situation is less clear with respect to the side effects of this procedure. The goal of this study was to correlate the coordinate values of active electrode contacts with the amplitude of residual clinical symptoms and side effects using a mathematical approach. Methods. In this study the investigators examined a cohort of 41 patients with PD who received clinical benefits from DBS after stimulating electrodes had been implanted bilaterally into the STN. The combined scores of residual clinical symptoms plus side effects, including speech disturbance, postural instability, and weight gain, were fitted by using either inverted ellipsoidal exponentials or smooth splines. These analyses showed evidence of lower combined scores for stimulating contacts at an x coordinate approximately 12.0 to 12.3 mm lateral to the anterior commissure-posterior commissure (AC-PC) line and at a z coordinate approximately 3.1 to 3.3 mm under the AC-PC line. There was insufficient evidence for a preferred y coordinate location. Conclusions. The authors propose a best therapeutic ellipse area that is centered at an x, z location of 12.5 mm, -3.3 mm and characterized by an extension of 1.85 mm in the x direction and 2.22 mm in the z direction. Therapeutic electrode contacts located within this area are well correlated with the lowest occurrence of residual symptoms and the lowest occurrence of side effects independent of STN anatomical considerations. The lack of a significant result in the y direction remains to be explored further.

Long thoracic neuropathy caused by an apical pulmonary tumor

Long thoracic nerve palsy has been reported to have traumatic, iatrogenic, and idiopathic causes. The authors describe the case of a 62-year-old man who presented with progressively worsening right shoulder pain, winging of the scapula, and Horner syndrome. A chest CT scan revealed an apical pulmonary mass. To the authors knowledge, this is the first report of a long thoracic nerve palsy caused by an apical pulmonary tumor.