Abstract
The Pan American Congress of Neurology was organized by the Bolivian Society of Neurology on behalf of the World Federation of Neurology in La Paz, Bolivia. Aging and dementia was one of the main congress tracks that has been highlighted in recent Latin American research in the field, focusing specifically on epidemiological studies, the economic cost of dementia and new Alzheimer’s disease (AD) biomarkers. A 4-year follow-up study of AD biomarkers was discussed and a survey was conducted in Argentina on the opinion of the general population in relation to the clinical use of these biomarkers, and early diagnosis criteria of AD were presented. In parallel, a newly developed Neurology International Conference for Primary Care was run that was designed for the education of more than 350 general practitioners from all the regions of Bolivia.
Keywords::
Pan American Congresses are the regional meetings of the World Federation of Neurology that are held every 4 years. The first Pan American Congress took place in Lima, Peru, in 1963, and was run by J Oscar Trelles, the famed Latin American neuroscientist and Prime Minister of Peru Citation[1]. The objective of Pan American Congresses is to highlight neurology and its recent advances in the host country.
In March 2012, the 13th Pan American Congress of Neurology was organized in La Paz, Bolivia, by Juan Carlos Durand Quiroz and his colleagues from the Bolivian Society of Neurology on behalf of the World Federation of Neurology – an umbrella organization representing national and regional societies of neurology. The official congress language was Spanish. The congress attracted more than 500 delegates from approximately 20 countries of America.
The congress offered a program developed by an international panel of experts, with the assistance of a brilliant scientific committee. It therefore provided an excellent opportunity for continued education in all fields of neurology. The scientific program included ‘state-of-the-art’ lectures in parallel sessions, together with volunteer oral communications and several hundred posters. Abstracts were reviewed and assigned to appropriate sessions. Accepted abstracts will be available on a CD-ROM to be distributed at the congress. A limited number of abstracts were scheduled for oral presentation. The program had parallel sessions focusing on epilepsy, cerebrovascular disease, epidemiology, movement disorders, and headache, as well as aging and dementia.
The aging and dementia track was organized by Raul Arizaga and his colleagues from the Research Group on Dementia from the World Federation of Neurology in two sessions and consisted of eight lectures and several sessions of oral communications and posters.
Epidemiology of dementia in Latin America
A review of epidemiology of dementia in Latin America (LA) was presented by Ricardo Nitrini (University of Sao Paulo, Brazil). Dementia has become a major public health problem in the region. Eight epidemiological studies have been carried out in different countries of LA (Cerro, Uruguay; Concepcion, Chile; Catanduva and Sao Paulo, Brazil; Maracaibo, Venezuela; La Habana, Cuba; Piraju, Brazil; and Lima, Peru), but these were relatively unknown to the neurological international community because they were published in local or regional journals. Nitrini’s lecture showed that the global prevalence of dementia in the elderly (≥65 years of age) in LA was 7.1% (95% CI: 6.8–7.4), mirroring the rates found in developed countries. However, the prevalence in relatively young subjects (65–69 years) was higher in the LA studies. The rate of illiteracy among the elderly was 9.3%, and the prevalence of dementia in illiterates was two-times higher than in the literates. Alzheimer’s disease (AD) was the most common cause of dementia. The higher prevalence of dementia in relatively young subjects may be related to the association between low education level and lower cognitive reserve, causing earlier emergence of clinical signs of dementia in the LA elderly population Citation[2].
Economic costs of dementia in LA
New data about the economic costs of dementia in Argentina were presented by Ricardo F Allegri (University of Buenos Aires, Argentina). There was limited information about the economic costs of dementia in South America.
Allegri showed that the annual direct costs of patients with AD in Argentina increased with cognitive deterioration from US$3420.4 in mild AD to US$9657.6 in severe AD, and with institutionalization (US$3189.2 for outpatients vs US$14, 447.68 for those institutionalized) Citation[3]. In LA, most direct costs were paid for by the family because social security was limited in this region. Another study comparing the differential costs of various subtypes of dementia Citation[4] showed that the annual direct costs were US$4625 for dementia of Alzheimer’s type (DAT), US$4924 for frontotemporal dementia (FTD) and US$5112 for vascular dementia (VaD; p > 0.05 between groups). In the post-hoc analysis, VaD showed higher hospitalization costs than DAT (p < 0.001). VaD exhibited lower medication costs than FTD (p < 0.001). DAT exhibited higher antidementia drug costs, and FTD had higher psychotropic costs. In the multivariate analysis, depression, activities of daily living and caregiver burden were correlated with direct costs (r2 = 0.76). With an increasing aging population in our region, analyses of health resource distribution in dementia patients and the resultant healthcare policies have become indispensable.
AD biomarkers in South America
A promising advancement in making early diagnosis of AD possible has been the development of biomarkers. Recently, in 2011, after gathering evidence from multiple trials and publications on biomarkers, the National Institute on Aging has issued new diagnostic recommendations for dementia and for mild cognitive impairment (MCI) due to AD Citation[5,6]. Levels of Aβ42, total tau (tau-t) and tau phosphorylated at position 181 (tau-p) in the cerebrospinal fluid (CSF) are one of the widely recognized biomarkers for AD. The decrease in CSF Aβ42 pathologically correlates with the accumulation of β-amyloid, whereas the increased tau-t and tau-p indicate deposition of neurofibrillary tangles and neuronal degeneration. The first report of a long follow-up with AD biomarkers in LA was presented by Jorge Campos (FLENI, Buenos Aires, Argentina). He described a 4-year follow-up of 20 patients (ten MCI, seven AD and three FTD) studied with CSF biomarkers (Aβ42, total-tau and phospho-tau 181). Longitudinal analysis confirmed that MCI patients with positive risk for AD (n = 5) showed an outright decline in their scores of Mini Mental State Exam and worsening in their Clinical Dementia Rating status (p < 0.05). Four of these patients had clinically probable AD. The remaining MCI patients with negative or intermediate risk for AD (n = 5) had no significant changes in their scores. Only one patient progressed to probable dementia. The final analysis at the end of the study showed that patients with higher clinical progression (worsening of Mini Mental State Exam and Clinical Dementia Rating scores) in the MCI group and AD had the lowest values of Aβ42, Aβ42/tau-p and profile for AD in CSF and higher values in tau-t and tau-p compared with the group of patients with MCI who did not progress to AD and FTD. In this context, CSF biomarker analysis allows an approach to the physiopathological process underlining AD, possibly leading to a more accurate diagnosis. In addition, the presence of CSF biomarkers in preclinical and prodromic phases can improve the estimation of conversion to AD and would permit an earlier diagnosis of the disease.
Survey about early diagnosis of AD
The results of a survey applied to 360 normal subjects from the general population in Buenos Aires were presented by Pablo Bagnati (University of Buenos Aires, Argentina) Citation[7]. The results of the survey indicated that AD was the third biggest health fear after cancer and stroke. A total of 85% of the participants identified the common symptoms (forgetfulness), and approximately 40% considered it to be fatal disease. More than 90% of the people said that they would want to know the true diagnosis if they had the disease and 80% of the participants agreed to make an ancillary study to confirm the diagnosis at the preclinical state of AD. Only 50% in this situation said that they would accept a lumbar puncture for early diagnosis. Bagnati discussed how the public opinion survey shows the level of fear and concern in relation to the disease, but it was interesting to see that most of the people prefer to know the diagnosis. This demonstrated a big change in the attitude of Latin American people, because a few years ago, doctors usually assumed that patients did not want to know their AD or dementia diagnosis. The other surprise was that most of the people would like to know about the disease even in its preclinical state because they wish to be in control of what happens in the future. This survey provided a very important ethical context to the development of new biomarkers and the possibility of very early diagnosis; the opinion of patients in relation to the clinical use of these biomarkers should be considered.
Neurology International Conference in primary care
One of the most exciting events of the meeting was a neurological conference in primary care organized in parallel with the main congress by Silvia Kochen (University of Buenos Aires, Argentina) and Maria Cusicanqui (Society of Neurology, La Paz, Bolivia) on behalf of the World Federation of Neurology, the Pan American Society of Neuro-epidemiology and in agreement with the health authorities of Bolivia.
The conference was organized as a 5-day course (covering stroke, epilepsy, dementia, headache and CNS infections) with 20 days of teaching, divided into 4 h per day. Each session was presented by a leading neurology specialist from different parts of the world. There were 350 participants enrolled in total (most of them general practitioners [GPs]), but admission was reduced to approximately 100 attedees due to a lack of space in the event venue. This course was very important because it was organized specifically for GPs and was presented in simple language with practical diagnostic and treatment protocols. Each participant received a CD with all the materials presented in each class. It was the first time that an extension of an international neurological congress was used for teaching local GPs, and Kochen proposed that this should be replicated at the next Pan American Congresses of the region.
Conclusion
The lectures in aging and dementia at the 13th Pan American Congress brought together an extraordinary spectrum of understanding and expertise in the field of cognitive impairment and dementia in the underdeveloped countries, which may impact powerfully on the health system. They also provide useful data as models for planning and defining aging health policies in at the region.
Financial & competing interests disclosure
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
No writing assistance was utilized in the production of this manuscript.
References
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