Blanc · Journal of Alzheimer's disease : JAD 2014 · prospective case series · n=20

Lyme neuroborreliosis and dementia.

Cited 49 times in the scientific literature.

Level 4 - case-series / case-control

Prospective case series without an uninfected control group

PubMed 24762944 · doi:10.3233/JAD-130446 · record verified 2026-08-30

What was done

Among 1,594 patients evaluated for dementia, researchers prospectively identified and studied 20 patients (1.25%) with dementia and a positive intrathecal anti-Borrelia antibody index. Patients underwent neuropsychological testing, brain MRI, FDG-PET, and cerebrospinal fluid analysis including tau, p-tau, and Aβ42. Etiological diagnoses were determined over a follow-up period of 5.0 ± 2.9 years after antibiotic treatment.

What was found

Two distinct patient groups were observed after antibiotic therapy. The first group (n = 7, 0.44%) had certain neuroborreliosis, showed stability or mild improvement of dementia after antibiotics, and had normal CSF tau, p-tau, and Aβ42. The second group (n = 13, 0.81%) showed progressive worsening of dementia despite antibiotics, with final diagnoses of Alzheimer's disease (n = 4), Alzheimer's disease plus Lewy body disease (n = 3), Lewy body disease (n = 1), frontotemporal lobar degeneration (n = 3), hippocampal sclerosis (n = 1), and vascular dementia (n = 1), alongside coherent abnormal CSF markers. Baseline cognitive tests showed no difference between groups. Brain MRI showed more focal atrophy and FDG-PET showed more frontal hypometabolism in the worsening group.

Why it matters

Pure Lyme dementia is a treatable condition that can stabilize or improve after antibiotics, whereas positive Borrelia antibodies may also coincide with progressive, irreversible neurodegenerative diseases.

Limits

The study is limited by a small sample size (n = 20), an uncontrolled observational design, and lack of a comparison cohort. The abstract reports no baseline or follow-up numerical cognitive test scores, test score differences, or confidence intervals.

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