Diagnosis of Alzheimer's disease in Brazil: Supplementary exams

Abstract

This article presents a review of the recommendations on supplementary exams employed for the clinical diagnosis of Alzheimer’s disease (AD) in Brazil published in 2005. A systematic assessment of the consensus reached in other countries, and of articles on AD diagnosis in Brazil available on the PUBMED and LILACS medical databases, was carried out. Recommended laboratory exams included complete blood count, serum creatinine, thyroid stimulating hormone (TSH), albumin, hepatic enzymes, Vitamin B12, folic acid, calcium, serological reactions for syphilis and serology for HIV in patients aged younger than 60 years with atypical clinical signs or suggestive symptoms. Structural neuroimaging, computed tomography or – preferably – magnetic resonance exams, are indicated for diagnostic investigation of dementia syndrome to rule out secondary etiologies. Functional neuroimaging exams (SPECT and PET), when available, increase diagnostic reliability and assist in the differential diagnosis of other types of dementia. The cerebrospinal fluid exam is indicated in cases of pre-senile onset dementia with atypical clinical presentation or course, for communicant hydrocephaly, and suspected inflammatory, infectious or prion disease of the central nervous system. Routine electroencephalograms aid the differential diagnosis of dementia syndrome with other conditions which impair cognitive functioning. Genotyping of apolipoprotein E or other susceptibility polymorphisms is not recommended for diagnostic purposes or for assessing the risk of developing the disease. Biomarkers related to the molecular alterations in AD are largely limited to use exclusively in research protocols, but when available can contribute to improving the accuracy of diagnosis of the disease.

Index of Alpha/Theta Ratio of the Electroencephalogram: A New Marker for Alzheimer’s Disease

“…The experimental group comprised 50 patients (19 men and 31 women) diagnosed with probable AD, according to NINCDS-ADRDA criteria (McKhann et al, 1984), of mild to moderate severity, based on DSM-IV R criteria, and with scores on the MMSE of between 12 and 25 points (Ordinance of The Health Care Secretariat/Brazilian Ministry of Health, 2002). All patients were recruited from the Outpatient Clinic of the Cognitive and Behavioral Neurology Group (GNCC) of the Division of Clinical Neurology of the HCFMUSP and/or from the CEREDIC of the HCFMUSP, and were submitted to routine outpatient assessment for diagnosing AD (Caramelli et al, 2011). The control group comprised normal subjects (29 men and 28 women) with scores on the MMSE ≥26 and older than 50 years, drawn from a database held by the neurophysiology service of the Referral Center for Cognitive Disorders (CEREDIC) (Caramelli et al, 1999).…”

BsmI polymorphism in the vitamin D receptor gene is associated with 25-hydroxy vitamin D levels in individuals with cognitive decline

“…The pathology is characterized by the presence of β-amyloid (Aβ) plaques and neurofibrillary tangles caused by hyperphosphorylation of the tau protein 2 . These processes have been used as biomarkers in cerebrospinal fluid, associated with functional neuroimaging, in order to provide a more accurate AD diagnosis 3 . Mild cognitive impairment (MCI) is a term used for individuals who have cognitive decline that is not enough to fulfill the diagnostic criteria for dementia, but which can be an intermediate stage between healthy cognitive aging and dementia.…”

Potential Biomarkers for Alzheimer’s Disease Screened in a Small Brazilian Population

“…3 To obtain blood samples from patients, such as serum, plasma and circulating cells is simple, therefore these are considered potential sources of biomarkers for AD diagnosis, research and clinical practice. 4,5 Plasmatic elements such as enzymes, glucose and lipids have been widely studied in AD´s patients. 6 Such plasmatic compounds would allow the implementation of effective preventive and therapeutic measures during the early stages of the disease, long before substantial cognitive impairment and brain structure´s decline.…”