Temporolimbic activation by intracranial electrical stimulation.

BACKGROUND: To evaluate the results of intracranial electrical stimulation (ICES) as a pre-surgical tool in order to select the side of the operation in bitemporal lobe epilepsy (BTLE) patients who underwent depth electrode (DE) implantation. METHODS: We reviewed the files of 77 medically intractable BTLE patients who underwent ICES with positive results through implanted DEs and then were under surgical treatment. One year or more after surgery, we evaluated the outcome. ICES was performed through: 1) Square-wave bipolar stimulation with symmetrical pulses of 60 Hz for 0.5 ms was delivered by a constant current Nuclear Chicago stimulator; 2) An initial intensity of 0.5 mA, and subsequently progressively stronger currents at 1-2 and occasionally 3 or 4 mA; 3) The duration of a single stimulation was usually 5 seconds; 4) The volume of tissue effectively stimulated did not exceed 5 mm. RESULTS: We obtained habitual auras or seizures (clinical responses, CRs) in 74 patients and after-discharges, ADs in 61 of them, according to Engel's classification for post surgery outcomes. If CRs or ADs were obtained by stimulation of only one temporal lobe the result of epilepsy surgery tended to be better (Engel classes I or II) when the operation was done on the same side of positive CRs (15 cases) or ADs (14 cases), and tended to be worse (Engel classes III or IV) when the ICES had provoked bilateral responses or when the side operated on was contra-lateral to positive CRs (33 cases) or ADs (28 cases). Statistical analyses were performed in order to test these results and we found better post-operative results when the resection took place in the same side of positive responses to ICES (CRs: chi2 4.74 and p=0.0295; ADs: chi2 7.57 and p=0.0059). CONCLUSION: In addition to other methods (PET, MRI and neuropsychology) presurgical ICES can provide useful data in the process of identifying the temporal lobe to be targeted for resection in BTLE patients.

[Behavioural and psychological signs in dementia. Clinical features. Pharmacological and non-pharmacological treatment strategies]. / Trastornos psicóticos y de conducta en las demencias: clínica y estrategias terapéuticas farmacológicas y no farmacológicas.

In first term, we define the current concepts in regard to psychosis (delirium and hallucinations) and abnormal behaviours (aggression, depression and mood changes such as mania, apathy, anxiety, agitation and desinhibition) in dementia. We also review the most used drugs in order to control these symptoms (typical and atypical antipsychotics, anti-epileptic drugs, benzodiazepines, SSRI, memantine and AcheI). As well, we take in consideration pharmacokinetic and pharmacodynamic characteristics, relationship to aging and interactions of these medications. Finally, we briefly describe the management of non-pharmacological of the most common behavioural symptoms: disruptive conducts such as exaggerated responses to minimal stimuli, catastrophic reaction, violence, anger and hostility, wandering and sundowning. As well, we discuss how to manage sleep disturbances, sexual aggression, incontinence and dressing apraxia. Management of these conditions involves, in first term, a comprehensive understanding of the whole situation and identification of underlying possible causes will make possible to evaluate results. This approach will lead to a more rationale proposal of psychotherapeutic and behavioural techniques, and milieu modifications. Finaly, we consider safety patient's in the community as well as the risk of abuse originated in a non-healthy patient-caregiver relationship.

Metabotropic glutamate receptors and epilepsy.

Metabotropic glutamate receptors (mGluRs) play an important role in the initiation of ictal discharges by participating in the interictal-ictal transition, and may play a crucial role in recruiting normal brain tissue into synchronized discharges, thereby facilitating propagation of seizure activity. In this article we present a review of mGluRs and epilepsy studies. Structural features of mGluRs offer multiple possibilities for synthetic compounds to modulate their activity, and for many reasons these compounds are good candidates for therapeutic applications. Group I mGluRs enhance excitatory transmission as much as groups II and III mGluRs can modulate those effects. Finally, main avenues to induce epileptogenesis are considered: activation of Ca2+ channels and Ca2+/CaMKII cascade, overexpression of AMPA and/or KA receptors, enhanced NMDARs function, activation of protooncogenes leading to a steady epileptogenic state, enhancement of INaP currents, blockade of A and/or M K(+) currents, calcium channelopathies, diminished number of GABARs or functions, and down-regulation of glutamate transporters. Deregulation of mGluR signaling functions including deficits in groups II and III mGluRs or hyperactivation of group I mGluRs may occur in some forms of epilepsy, therefore targeting these mechanisms with specific pharmacological tools could provide new developments for original therapeutic approaches.