The Clinical Impact of the Novel Alzheimer's Blood-based Biomarkers

The goal of this observational study is to determine whether the early adoption of blood-based biomarkers for Alzheimer's disease is associated with an impact on etiological diagnosis, patient's management, emotional impact, patient's preferences and cost-effectiveness in patients presenting with cognitive complaints in a Cognitive Disorders Unit from a public hospital.

The main questions it aims to answer are:

1. Does the early adoption of blood-based biomarkers in clinical practice enable an earlier etiologic diagnosis with high confidence compared to the late adoption of blood-based biomarkers in the patients with cognitive complaints that are admitted in a Cognitive Disorders Unit?
2. Is the early adoption of blood-based biomarkers in clinical practice associated with changes in clinical management compared to their late adoption?
3. Is the early adoption of blood-based biomarkers in clinical practice associated with a lower emotional impact in the patients and their study partners/caregivers compared to their late adoption?
4. Are blood-based biomarkers better tolerated than other tests and preferred by patients for the diagnostic work-up?
5. Does blood-based biomarkers have an impact in the cost of the diagnostic workup and clinical management of the patients that are admitted in a Cognitive Disorders Unit?

Participants will be asked to:

* Perform a blood extraction for blood-based biomarkers analysis at the beginning of the study.
* Complete specific scales in each visit.

Researchers will compare the group in which blood biomarkers are delivered at 3 months with the group in which they are delivered at 9 months to assess whether early adoption of blood-based biomarkers is associated with an impact on etiological diagnosis, patient's management, emotional impact, patient's preferences and cost-effectiveness in a specialized memory unit.

Blood-based biomarkers that accurately detect Alzheimer's disease (AD) and neurodegeneration now offer a realistic, cost-effective and non-invasive assessment that will aid the diagnostic process in patients presenting with cognitive clinical manifestations. Plasma measures of Amyloid-β (Aβ) 42/40, phosphorylated tau (p-tau) 181, p-tau217, p-tau231 and Glial fibrillary acidic protein (GFAP) have shown high diagnostic accuracy to detect AD, while plasma Neurofilament light chain (NfL) indicates neuronal injury. Despite these promising results, there is still no clear real-word evidence of their clinical applications. Here, the PLASMAR project aims to determine whether blood-based biomarkers have an impact on the clinical management of patients presenting with cognitive complaints in a Cognitive Disorders Unit from a public hospital, which provides care to a heterogeneous population. The project is divided into two specific objectives. First, the investigators will determine, in a research cohort, which blood biomarker or biomarkers' combination have the highest accuracy to detect AD. Second, a prospective clinical cohort of consecutive patients coming to the memory unit will be recruited. The investigators will assess whether early adoption of blood-based biomarkers is associated with an impact on etiological diagnosis, patient's management, emotional impact, patient's preferences and cost-effectiveness in a specialized memory unit. Answering the question of whether blood-based biomarkers have a clinical impact in the real-world scenario of a memory unit, the PLASMAR project is crucial for the healthcare system and can guide the developing of guidelines and protocols on the use of blood-based biomarkers.

Eligibility Criteria:
Inclusion Criteria:

* Subjects ≥18 and ≤85 years old of any sex, gender, race or ethnicity.
* Individuals interested in participating in the study who understand the procedures that will be performed.
* The patient must have a complaint (reported by the patient or by a study partner/caregiver) of cognitive or behavioral impairment.
* The patient must satisfy the clinical diagnostic criteria for subjective cognitive decline, mild cognitive impairment, or mild dementia (defined as a Global deterioration scale score equal to 4), and a neurodegenerative disease such as AD is considered in the differential diagnosis.
* Agreement to undergo all the study procedures, complete all clinical visits according to protocol and capacity to give informed consent.
* The patient has undergone (maximum 12 months ago) or will undergo a dementia blood workup and MRI and/or CT scan before V1.
* In dementia patients, a study partner must be available for the duration of the protocol.

Exclusion Criteria:

* Any significant systemic illness or unstable medical condition that could make it difficult to comply with the protocol.
* Medical contraindications for any of the study procedures.
* Available AD's cerebrospinal fluid biomarkers levels or amyloid-PET at screening.
* The patient comes to the Memory Unit for reasons other than cognitive or behavioral impairment.
* Patients in which an etiological diagnosis is already made.
* The patient is currently participating or has participated in a clinical trial with an investigational pharmaceutical product.
* Women who are pregnant, planning to become pregnant, or lactating.