The neurologist facing pain in dementia.

INTRODUCTION: Ageing, a common background in dementia, is usually associated with painful disorders. Nevertheless, the use of analgesics is limited due to poor communication. On the other hand, dementia lesions are placed in the nociceptive pathways. For this reason, the painful experience becomes different and distinctive for every lesional type. COURSE: The lateral nociceptive pathway (lateral thalamic nuclei and primary parietal cortex), which is in charge of the primary pain perception, is preserved in dementia. Thereafter, the shear painful perception, including pain intensity and threshold, remains unmodified. Distinctly, the medial pain pathways are affected by dementia lesions. In this pathway are included: the intralaminar thalamic nuclei, the pons (locus ceruleus:LC), the mesencephalon (periaacueductal grey substance: PGS), the hypothalamus (paraventricular nuclei, mamilary tuberculum) and different areas of the parietal (primary, secondary, operculum), temporal (amigdala, hypoccampus) and frontal (anterior cingular: ACC). As a consequence, the features of pain executed by these areas will be compromised: the cognitive assessment, the mood and emotion inherent to pain, the pain memory or the autonomic responses are modified in dementia. Specifically, in Alzheimer's disease (AD) there is a reduction in the anticipatory and avoidance responses and also a flattening of the autonomic responses. These are essentially secondary to the degenerative changes in the medial temporal (pain memory) and ACC (cognitive and mood aspects) areas. In vascular dementias, there is a cortico-subcortical deafferentation secondary to the white matter lesions. The consequence is the presence of hyperpathy and hyperalgesia. In the frontotemporal dementias, there is a reduction in pain expressivity. It is linked to the lesions in the orbitofrontal and anterior temporal areas, which are responsible of the emotional aspects of pain. In Parkinson's disease, painful conditions are a common characteristic. They are attributed to an early lesion in the LC, which reduces its prominent antinociceptive activity. Finally, in the demented patients there is a lack of expectations to analgesic treatments. This means an absence of the placebo effect, which is, alongside the pharmacokinetic action, an inherent part of the analgesic response. The placebo response is related to activity in the ACC and PGS. Giving its lack, higher doses of analgesics are necessary in dementias. CONCLUSIONS: The assessment of pain in dementia is rather complex, which is the main reason for the scarcity of the analgesic treatment in dementias. It must be specific and systematic. For this purpose, the pain scales are a useful tool. For communicative patients, simple visual scales are helpful, meanwhile in the non-communicative patients the multidimensional scales are the most suitable. By this means, the expressive, motor, emotional, functional and social interactions are evaluated. Pain may be responsible of progression and cognitive deterioration in dementia. This evolution could be reversible, and consequently it has to be foreseen in order to implement analgesic treatment. Trying to minimize adverse events, it has to be potent but closely monitored.

[Zonisamide in the preventive treatment of refractory migraine]. / Zonisamida en el tratamiento preventivo de la migraña refractaria.

INTRODUCTION: Chronic migraine refractory to preventive treatment is a common clinical situation in general neurology clinics. The aim is to analyse our experience with zonisamide in the preventive treatment of patients with frequent refractory migraine. PATIENTS AND METHODS: Those patients with no response or intolerance to topiramate and at least one more preventative received zonisamide. This drug was increased 25 mg per week up to 200 mg/day. The efficacy of zonisamide was evaluated in terms of 'response' (reduction in attack frequency below 50%) at the third month of treatment. RESULTS: Our series comprises a total of 172 patients, with ages ranging from 22 to 69 years. 85% were women. The final dosage of zonisamide was 50-200 mg/day, with the 100 mg/day being the most frequently administered dose. Zonisamide was efficacious (response) in 76 (44%) patients; response being excellent in 22 (13%). MIDAS score was reduced by 43.2%. Zonisamide was not tolerated by 27% of the patients, mainly due to subjective mental slowness or digestive symptoms. CONCLUSIONS: These results, obtained in a big sample of patients refractory or intolerant to topiramate and other preventatives, indicate that, at least in conditions of daily clinical practice, zonisamide, at relatively low dosages, is an option to be considered for the preventive treatment of patients with frequent migraine.