Early Detection

Psychophysical DetectionDr. Charles J. Duffy—MD, PhD, and CAS Founder and CEO—began his investigation by conducting cognitive psychophysical studies demonstrating specific deficits in human aging and AD (Tetewsky, 1999; O’Brien, 2001).

This led to studies showing the independence of these deficits from memory deficits (Mapstone, 2003) and attentional deficits (Kavcic, 2003).

Separate Deficits

Cognivue Separate Deficits

Dr. Duffy then expanded the studies, distinguishing deficits related to aging and AD (Mapstone, 2006, 2008, 2010; Velarde, 2012).

Neural Mechanisms

Neural Mechanisms

Dr. Duffy’s studies of functional impairment led to development of new technologies for recognizing and characterizing cognitive impairment (Monacelli, 2003), including virtual-reality test batteries (Cushman, 2007; 2008).

A series of related studies using a psychophysical approach linked the behavioral research with the neurophysiological research to define the neural mechanisms of impairment in aging and AD (Kavcic, 2008; Fernandez, 2007, 2012, 2013; Jacob, 2014).

Bottom-up (Sensory) and Top-down (Control) Signals

Brain Sensory

When interconnections emanate from sensory areas, carrying sensory input signals to a part of the brain, they are commonly referred to as bottom-up signals. When those interconnections emanate from motor areas, carrying task-specific control signals to a part of the brain, they are commonly referred to as top-down signals. Each area devoted to a specific brain function receives some combination of both bottom-up sensory signals and top-down control signals.

The Cognivue Solution: Psychophysical Profiles

Cognivue Bottom-Up Processing

The Cognivue cognitive psychophysical approach presents sensory signals to activate the perceptual and memory functions of various brain systems. Plus, it provides consistent rotatory response tasks to normalize the influence of top-down control signals.

This combination of approaches provides the opportunity to measure the perceptual and memory functional abilities across select, specific functional domains.

Cognivue manipulates the strength of the bottom-up signals to quantify domain-specific perceptual processing abilities. And superimposes an interfering mask stimuli of varying durations to quantify domain-specific memory processing abilities.

Summary of Clinical Research Related to the Development of Cognivue

More than 20 scientific references and brief summaries of research on clinical populations that included the cognitive psychophysical approach and contributed to the experimental foundations of Cognivue technology can be found below:

Alzheimer’s Disease Blocks Cortical Responses

Approaching Objects Cause Confusion in Patients with AD

At the Interface of Sensory and Motor Dysfunctions and AD

Attentional Dynamics and Visual Perception

Consequences of Optic Neuritis CAS

Cortical Motion Blindness in Visuospatial AD

Cue Integration for the Perception and Control of Self-Movement in Ageing and AD

Detecting Navigational Deficits in Cognitive Aging and AD Using VR

Distinct Mechanisms of Impairment in Ageing and AD

Distinct Visual Motion Processing Impairments in Aging and AD

Early AD Blocks Responses to Accelerating Self-Movement

The Legacy of Association Cortex

Might Cortical Hyper-Responsiveness in Aging Contribute to AD

Navigational Impairment in Alzheimer’s Disease

Navigational Path Integration By Cortical Neurons

neurophysiologic Analyses of Low and High Level Visual Processing in AD

Optical Flow Fields in Alzheimer’s Patients

Posterior Cortical Dementia

Receptive Field Dynamics Underlying MST Neuronal Optic Flow Selectivity

Sex Specificity of Navigational Strategies in AD

Spatial Disorientation in AD

Visual Mechanisms of Spatial Disorientation in AD

Visual Motion ERPS Distinguish Aging and AD

Visual Motion Processing Impairments in Aging

Visual Word and Motion Processing in Alzheimer’s

Visuospatial Variant of Mild Cognitive Impairment 



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