Retinal Neuro-vascular Coupling in Patients With Neurodegenerative Disease

  • STATUS
    Recruiting
  • End date
    Sep 30, 2023
  • participants needed
    150
  • sponsor
    Medical University of Vienna
Updated on 24 April 2022
cognitive impairment
dementia
mini-mental state examination
alzheimer's disease
mild cognitive impairment
mental state examination
neurodegenerative disorders
neuropsychological test
cognitive assessment
Accepts healthy volunteers

Summary

Alzheimer´s disease (AD) in one of the most important causes of dementia and poses a considerable challenge in health care. Today, criteria for the diagnosis and the follow up of patients with AD mainly rely either on subjective tests or invasive methods. This limits the general applicability of the latter test for population screening and underlines the need for the identification of easily accessible tools for the identification of high-risk subjects. Because of its unique optical properties, the eye offers the possibility of the non-invasive assessment of both structural and functional alterations in neuronal tissue. As the neuro-retina is part of the brain, it does not come as a surprise that neuro-degenerative changes in the brain are accompanied by structural and possibly also functional changes in the neuro-retina and the ocular vasculature. The current study seeks to test the hypothesis that beside the known anatomical changes, also functional changes can be detected in the retina of patients with AD. For this purpose, flicker light induced hyperemia will be measured in the retina as a functional test to assess the coupling between neural activity and blood flow. Further, structural parameters such as retinal nerve fiber layer thickness and function parameters such as ocular blood flow and retinal oxygenation will be assessed and compared to age and sex matched controls.

Details
Condition Mild Cognitive Impairment, Alzheimer Disease, Healthy
Treatment Optical Coherence Tomography, FDOCT, DVA, DVA, Pattern ERG
Clinical Study IdentifierNCT02663531
SponsorMedical University of Vienna
Last Modified on24 April 2022

Eligibility

Yes No Not Sure

Inclusion Criteria

Inclusion criteria for healthy subjects
Men and women aged over 50 years
Non-smokers
Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant
Normal ophthalmic findings, ametropia < 6 Dpt
Inclusion criteria for patients with AD
Men and women aged over 50 years
Normal ophthalmic findings, ametropia < 6 Dpt
Confirmed diagnosis of probable AD of mild to moderate degree defined as
Diagnosis of probable Alzheimer's disease based on the NINCDS/ADRDA criteria
Assessing the severity of Alzheimer's disease of mild to moderate degree by the Mini Mental State Examination (MMSE). AD of mild to moderate degree has been confirmed if the MMSE score is in the range of 20 to 26 inclusive
Hachinski Ischemia Scale is used to try and distinguish AD from multi-infarct
Adequate visual and auditory acuity to allow neuropsychological testing and participation in the ocular blood flow measurements
dementia. A score of ≤ 4 suggests AD Informed consent capability
A potential participant has to be on stable doses of all medications he/she is taking because of consisting illnesses according to medical history (except AD therapy itself which will be recorded separately) for at least 30 days prior inclusion, if considered relevant by the investigator
Inclusion criteria for patients with mild cognitive impairment
Men and women aged over 50 years
Normal ophthalmic findings, ametropia < 6 Dpt
Diagnosis of probable mild cognitive impairment (MCI) defined as
memory complaint, corroborated by an informant
normal general cognitive function, as determined by a clinician's judgment based on a structured interview with the patient and an informant (Clinical Dementia Rating [CDR]) and a Mini-Mental State Examination (MMSE) score greater than 26
abnormal memory function, documented by delayed recall of one paragraph from the Logical Memory II subtest of the Wechsler Memory Scale-Revised (cutoff scores: ≤8 for ≥16 years of education; ≤4 for 8 to 15 years of education; and ≤2 for 0 to 7 years of education [the maximum number of paragraph items possible to correctly recall is 25])
no or minimal impairment in activities of daily living (ADLs), as determined by a clinical interview with the patient and informant
not sufficiently impaired, cognitively and functionally, to meet the NINCDS/ADRDA criteria, as judged by an experienced AD research clinician
Hachinski Ischemia Scale is used to try and distinguish MCI from multi-infarct
Adequate visual and auditory acuity to allow neuropsychological testing and participation in the ocular blood flow measurements
dementia. A score of ≤ 4 suggests MCI Informed consent capability
A potential participant has to be on stable doses of all medications he/she is taking because of consisting illnesses according to medical for at least 30 days prior inclusion, if considered relevant by the investigator

Exclusion Criteria

Presence or history of a severe medical condition other than cognitive impairment as judged by the clinical investigator
Untreated Arterial hypertension
History or family history of epilepsy
Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator
Best corrected visual acuity < 0.5 Snellen
Ametropia greater than 6 Dpt
pregnancy or planned pregnancy
Major psychiatric disorder (e.g. schizophrenia), if considered relevant by the investigator
Significant neurological disease other than AD or MCI, if considered relevant by the investigator
Alcoholism or substance abuse
Exclusion criteria for healthy volunteers
Presence or history of a severe medical condition as judged by the clinical investigator
Untreated Arterial hypertension
History or family history of epilepsy
Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator
Family history of AD
Best corrected visual acuity < 0.5 Snellen
Ametropia 6 Dpt
Pregnancy or planned pregnancy
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