Emergence of hyper empathy after right amygdalohippocampectomy

We report a fascinating case of a patient with a hyper empathy that appeared after resective epilepsy surgery. This behavioral modification has remained unchanged since the surgery took place 13 years ago. Recent neuropsychological objective assessments confirmed hyper empathy in a self-report questionnaire, and revealed higher affective theory of mind than controls in a "Reading the Mind in the Eyes Task." Temporal lobe epilepsy is the most common form of epilepsy and the investigation of emotional processes after surgery in these patients deserves to be related.

Pneumatic evoked potential. Sensory or auditive potential?

STUDY AIM

In this study, evoked potentials (EPs) to a pneumatic, innocuous, and calibrated stimulation of the skin were recorded in 22 volunteers.

METHODS

Air-puff stimuli were delivered through a home-made device (INSA de Lyon, Laboratoire Ampère, CHU de Saint-Étienne, France) synchronized with an EEG recording (Micromed(®)).

RESULTS

A reproducible EP was recorded in 18 out of 22 subjects (82% of cases) with a mean latency of about 120-130ms, and maximal amplitude at Cz. This EP actually consisted of two components, an auditory and a somatosensory one. Indeed, it was significantly decreased in amplitude, but did not disappear, when the noise generated by the air-puff was masked. We also verified that a stimulation close to the skin but not perceived by the subject was not associated with any EP. Conduction velocity between hand and shoulder was calculated around 25m/s.

CONCLUSIONS

This preliminary study demonstrates that pneumatic EPs can be recorded in normal volunteers.

Explicit and implicit emotional processing modifications in pharmacoresistant left temporal lobe epilepsy and anxiodepressive disorders

We examined whether anxiodepressive patients with left temporal lobe epilepsy could be differentiated from those with depression but without epilepsy on tasks that investigate attentional bias toward and explicit judgment of emotional stimuli. Eight depressive patients, eight anxiodepressive patients with epilepsy, and eight controls participated in the present study. Anxiodepressive with epilepsy and depressive patients had comparable depression scores and the same cognitive profile. Two distinct emotional tasks were used: the decision lexical task and the number comparison task. Three emotional connotations were presented: neutral, positive, and negative. The pattern of results showed an attentional bias toward negative words and pictures in depressive patients and only toward negative words in anxiodepressive patients with epilepsy. Moreover, depressive patients explicitly judged negative stimuli with lower intensity and anxiodepressive patients judged neutral stimuli with higher intensity. The present study specifies the emotional functioning in depression with or without left temporal lobe epilepsy.

Sensory and motor neuronopathy in a patient with the A382P TDP-43 mutation

Patients with TARDBP mutations have so far been classified as ALS, sometimes with frontal lobe dysfunction. A 66-year-old patient progressively developed a severe sensory disorder, followed by a motor disorder, which evolved over nine years. Symptoms started in the left hand and slowly involved the four limbs. Investigations were consistent with a mixed sensory and motor neuronopathy. A heterozygous change from an alanine to a proline at amino acid 382 was identified in exon 6 of the TARDPB gene (p.A382P). This case expands the phenotypic spectrum associated with mutations in the TARDBP gene and shows that sensory neurons can be severely damaged early in the course of the disease, following a propagating process, with an orderly progression from a focal starting point. A combination of severe sensory and motor neuronopathy is rarely encountered in clinical practice. The possibility of an A382P TDP-43 mutation should be considered in patients with such an association.

How a clock can change your pain? The illusion of duration and pain perception

The intensity of experimental pain is known to be dependent on stimulation duration. However, it remains unknown whether this effect arises largely from the actual stimulus duration or is substantially influenced by the subject's perception of the stimulus duration. In the present study, we questioned this issue by misleading the perception of the duration of pain in a population of 36 healthy volunteers stimulated with a thermode. To this aim, time was signified by a clock with rotating hands in which imperceptible differences in speed rotation had been introduced. Subjects were therefore immersed in 2 comparative conditions in which time was manipulated to provide the illusion of either long or short duration of the painful stimulus. In a first condition ("full-length" clock), participants were instructed that pain would last for a complete revolution of the clock's hands, whereas in the second condition ("shortened" clock), revolution was reduced by 25%. Although the intensity and the real duration of stimulation were identical in both conditions, the intensity of pain was significantly reduced when the perception of time was misleadingly shortened by the manipulated clock. This study suggests that the perceived duration of a noxious stimulation may influence the perceived intensity of pain. The perceived duration of the length of a noxious stimulation influences (decreases) the intensity of perceived pain.

Operculo-insular pain (parasylvian pain): a distinct central pain syndrome

Central pain with dissociated thermoalgesic sensory loss is common in spinal and brainstem syndromes but not in cortical lesions. Out of a series of 270 patients investigated because of somatosensory abnormalities, we identified five subjects presenting with central pain and pure thermoalgesic sensory loss contralateral to cortical stroke. All of the patients had involvement of the posterior insula and inner parietal operculum. Lemniscal sensory modalities (position sense, graphaestesia, stereognosis) and somatosensory evoked potentials to non-noxious inputs were always preserved, while thermal and pain sensations were profoundly altered, and laser-evoked potentials to thermo-nocoiceptive stimuli were always abnormal. Central pain resulting from posterior parasylvian lesions appears to be a distinct entity that can be identified unambiguously on the basis of clinical, radiological and electrophysiological data. It presents with predominant or isolated deficits for pain and temperature sensations, and is paradoxically closer to pain syndromes from brainstem lesions affecting selectively the spinothalamic pathways than to those caused by focal lesions of the posterior thalamus. The term 'pseudo-thalamic' is therefore inappropriate to describe it, and we propose parasylvian or operculo-insular pain as appropriate labels. Parasylvian pain may be extremely difficult to treat; the magnitude of pain-temperature sensory disturbances may be prognostic for its development, hence the importance of early sensory assessment with quantitative methods.

Brain immunohistopathological study in a patient with anti-NMDAR encephalitis

BACKGROUND AND PURPOSE

Anti-N-methyl-D-asparate (NMDA) receptor encephalitis is thought to be antibody-mediated. To perform an immunohistopathological study of the inflammatory reaction in a brain biopsy performed before immunomodulatory treatments in a patient with anti-NMDA receptor encephalitis.

METHODS

An immunohistochemical study was performed using CD3, CD68, CD20, CD138 and CD1a antibodies.

RESULTS

Prominent B-cell cuffing was present around brain vessels accompanied by some plasma cells, while macrophages and T cells were scattered throughout the brain parenchyma.

CONCLUSION

These findings suggest that the B cells interact with the T cells and are involved in antibody secretion by the plasma cells.

[Differential diagnosis of status epilepticus]

The diagnosis of status epilepticus can be retained, wrongly, in several circumstances. Nonepileptic pseudoseizures from a psychiatric origin and some movement disorders can mimic convulsive status epilepticus. Encephalopathy of various causes (post-anoxic, metabolic, toxic, Creutzfeldt-Jakob disease) can be wrongly taken for non-convulsive status epilepticus, mainly due to inadequate interpretation of the electroencephalogram (EEG). In these encephalopathies, the existence of (non-epileptic) myoclonus and the abolition of the EEG abnormalities with the use of a benzodiazepine (without correction of the clinical symptoms) are additional confounding factors, leading to false diagnosis. Nevertheless, in general, the diagnosis of status epilepticus can be confirmed or rejected base on a combined analysis of the clinical data and the EEG.

An odd manifestation of the Capgras syndrome: loss of familiarity even with the sexual partner

We report the case of a patient who presented visual hallucinations and identification disorders associated with a Capgras syndrome. During the Capgras periods, there was not only a misidentification of his wife's face, but also a more global perceptive and emotional sexual identification disorder. Thus, he had sexual intercourse with his wife's "double" without having the slightest recollection feeling of familiarity towards his "wife" and even changed his sexual habits. To the best of our knowledge, he is the only neurological patient who made his wife a mistress. Starting from this global familiarity loss, we discuss the mechanism of Capgras delusion with reference to the role of the implicit system of face recognition. Such behavior of familiarity loss not only with face but also with all intimacy aspects argues for a specific disconnection between the ventral visual pathway of face identification and the limbic system involved in emotional and episodic memory contents.

Intérêt et limites de l’électroneuromyogramme pour explorer un membre supérieur douloureux

OBJECTIVE

To study the utility of electroneuromyography in analysis of upper limb pain as a function of the existence of a diagnostic hypothesis.

METHODS

We retrospectively compared the consecutive electroneuromyographic examinations performed between 1 January and 30 September 2004. All recordings were performed by the same examiner in the neurophysiology clinic in the department of neurology of Saint-Etienne university hospital UHC at the request of hospital specialists or surgeon and private general practitioners. In each examination, at a minimum and regardless of the specific situation, motor conduction speed, F waves, and sensory conduction speed were recorded for the median nerve and the ulnar nerve on the right and left. For the arm in question, needle electromyography explored the muscles depending on the C5-T1 roots.

RESULTS

In all, 76 patients had ENMG examinations, 38 for whom the physician had a diagnostic hypothesis and 38 patients without. In the case of a diagnosis based on clinical suspicions, examination was normal in 73.7% of cases compared with 23.7% when there was a clinically based hypothesis (p<0.01). These findings did not vary significantly according to the specialization of the referring physician.

CONCLUSION

Electromyography and nerve conduction studies are useful to confirm a diagnosis based on patient reports and clinical data, it is not useful when no diagnosis has been suggested.

Thalamic thermo-algesic transmission: ventral posterior (VP) complex versus VMpo in the light of a thalamic infarct with central pain

The respective roles of the ventral posterior complex (VP) and of the more recently described VMpo (posterior part of the ventral medial nucleus) as thalamic relays for pain and temperature pathways have recently been the subject of controversy. Data we obtained in one patient after a limited left thalamic infarct bring some new insights into this debate. This patient presented sudden right-sided hypesthesia for both lemniscal (touch, vibration, joint position) and spinothalamic (pain and temperature) modalities. He subsequently developed right-sided central pain with allodynia. Projection of 3D magnetic resonance images onto a human thalamic atlas revealed a lesion involving the anterior two thirds of the ventral posterior lateral nucleus (VPL) and, to a lesser extent, the ventral posterior medial (VPM) and inferior (VPI) nuclei. Conversely, the lesion did not extend posterior and ventral enough to concern the putative location of the spinothalamic-afferented nucleus VMpo. Neurophysiological studies showed a marked reduction (67%) of cortical responses depending on dorsal column-lemniscal transmission, while spinothalamic-specific, CO2-laser induced cortical responses were only moderately attenuated (33%). Our results show that the VP is definitely involved in thermo-algesic transmission in man, and that its selective lesion can lead to central pain. However, results also suggest that much of the spino-thalamo-cortical volley elicited by painful heat stimuli does not transit through VP, supporting the hypothesis that a non-VP locus lying more posteriorly in the human thalamus is important for thermo-algesic transmission.

An fMRI study of cortical representation of mechanical allodynia in patients with neuropathic pain

OBJECTIVE

To investigate cerebral activity associated with allodynia in patients with neuropathic pain.

METHODS

The brain responses of 27 patients with peripheral (5), spinal (3), brainstem (4), thalamic (5), lenticular (5), or cortical (5) lesions were studied with fMRI as innocuous mechanical stimuli were addressed to either the allodynic territory or the homologous contralateral region.

RESULTS

When applied to the normal side, brush and cold rubbing stimuli did not evoke pain and activated a somatosensory "control" network including contralateral primary (SI) and secondary (SII) somatosensory cortices and insular regions. The same stimuli became severely painful when applied to the allodynic side and activated regions in the contralateral hemisphere that mirrored the "control" network, with, however, lesser activation of the SII and insular cortices. Increased activation volumes were found in contralateral SI and primary motor cortex (MI). Whereas ipsilateral responses appeared very small and restricted after control stimuli, they represented the most salient effect of allodynia and were observed mainly in the ipsilateral parietal operculum (SII), SI, and insula. Allodynic stimuli also recruited additional responses in motor/premotor areas (MI, supplementary motor area), in regions involved in spatial attention (posterior parietal cortices), and in regions linking attention and motor control (mid-anterior cingulate cortex).

CONCLUSION

On a background of deafferentation in the hemisphere contralateral to stimuli, enhanced or additional responses to innocuous stimuli in the ipsilateral hemisphere may contribute to the shift of perception from innocuous toward painful and ill-defined sensations.

Laser-evoked potential abnormalities in central pain patients: the influence of spontaneous and provoked pain

We recorded laser-evoked cortical potentials (LEPs) in 54 consecutive patients presenting with unilateral neuropathic central pain (n = 42) or with lateralized pain of non-organic origin (n = 12). A number of cases in each group had superimposed hyperalgesia or allodynia. In patients with central pain, LEPs were significantly attenuated after stimulation over the painful territory, relative to stimulation of the homologous normal territory. LEP attenuation concerned not only patients with decreased pain/heat sensation, but also those with allodynia or hyperalgesia to laser pulses. In contrast, LEPs were never attenuated in patients with non-organic forms of pain, in whom LEPs could even be enhanced to stimulation of the painful territory. Increased responses in non-organic pain were a reminder of the cognitive modulation observed in normal subjects who direct attention to a laser stimulus. Enhanced LEPs never accompanied truly neuropathic hyperalgesia or allodynia. In central pain patients with exclusively spontaneous pain, LEP attenuation was more pronounced than that observed in those with allodynia and hyperalgesia. Patients with allodynia also presented occasionally ultra-late responses (>700 ms) to stimulation of the painful side. The hypothesis that such responses may reflect activation of a slow conducting 'medial' pain system is discussed. We conclude that, as currently recorded, LEPs essentially reflect the activity of a 'lateral' pain system subserved at the periphery by rapidly conducting A-delta fibres. They are useful to document the sensorial deficits (deafferentation) leading to neuropathic pain syndromes. Conversely, in the case of deafferentation, they fail to index adequately the affective aspects of pain sensation. On practical grounds, chronic pain coupled with reduced LEPs substantiates the diagnosis of neuropathic pain, whereas the finding of normal or enhanced LEPs to stimulation of a painful territory suggests the integrity of pain pathways, and does not support a neuropathic pathophysiology. In neuropathic cases, partial LEP preservation might increase the probability of developing provoked pain (allodynia/hyperalgesia). The possible predictive value of this phenomenon, when observed before the development of pain, remains to be demonstrated. In selected contexts (pain sine materia, non-organic anaesthesia), normal or enhanced LEPs may support a psychogenic participation in the syndrome.

[First epileptic seizure in the elderly: electroclinical and etiological data in 341 patients]

This study included 341 subjects aged over 60 years, 174 females and 167 males, (mean age 72-years), who experienced their first epileptic seizure and fulfilled all inclusion criteria over an 8-year period. Data were available from the physical examination, EEG, laboratory tests and CT scan or MRI for all patients. The international classification of epileptic seizures was applied, 41 p.cent of the seizures were generalized and 59 p.cent were partial. Status epilepticus occurred in 8 p.cent of the patients. The EEG recording was contributive to diagnosis or helpful for localizing the epileptic focus in 55 p.cent of the patients. Normal brain imaging was observed in 40 p.cent of the patients. The main etiology was cerebrovascular disease (33 p.cent), acute stroke (27 patients), or more often postvascular epilepsy (87 patients). Other etiologies were degenerative cortical dementia in 7 p.cent of the patients, metabolic and toxic disorders in 11 p.cent, and benign or malignant brain tumors in 6.5 p.cent. Thirty-two percent of the seizures were of unknown origin (cryptogenic seizures). No correlation was found between sex, age, and etiology. An antiepileptic drug treatment was initiated in 77 p.cent of the patients who were given either valproate (43 p.cent), carbamazepine (26 p.cent) or barbiturates (7 p.cent). These findings are in agreement with those reported in the reviewed literature.

Cognitive effects of precentral cortical stimulation for pain control: an ERP study

Electrical stimulation of the motor cortex (MCS) is a promising and increasingly used neurosurgical technique for the control of refractory neuropathic pain. Although its mechanisms of action remain unknown, recent functional imaging data suggest involvement of the thalamus, brainstem and anterior cingulate/orbitofrontal cortex. Since some of these areas are also implicated in higher cognitive functions, notably attentional processes, we analysed cognitive ERPs and behavioural performance during an "oddball" auditory detection task in patients submitted to this procedure. Eleven consecutive patients undergoing MCS because of neuropathic refractory pain, ranging in age from 25 to 71 years, were included in the study. ERPs were obtained in all cases both during the application ("MCS-on") and within the 10 min that followed discontinuation of the procedure ("MCS-off"). In five patients, ERPs could also be obtained just before the start of MCS. When the patients' sample was taken as a whole, there were no consistent effects of MCS on the ERPs. There was, however, a significant interaction of MCS action with the patients' age, reflecting a significant delay during MCS of the cognitive responses N2 and P3 (N200 and P300) in the group of patients older than 50 years exclusively. This effect was rapidly reversible after MCS discontinuation. No MCS-related changes were observed in the N1 component. At the individual level, the effect of MCS on the endogenous ERPs was highly variable, ranging from a total stability of ERPs (mostly in younger subjects) to latency differences of tens of milliseconds in the older group. These results, together with recent experiments showing P300 alteration during repetitive transcranial stimulation, suggest that motor cortex stimulation may interfere with relatively simple cognitive processes such as those underlying target detection, and that the risk of abnormal cognitive effects related to cortical stimulation may increase with age. Although the procedure appears on the whole remarkably safe, complementary neuropsychological studies in this category of patients are advised, as well as caution to possible adverse cognitive effects when using MCS in the elderly, notably in the presence of pre-existent cerebral lesions.