Advances in Assessment of Cognitive Impairment and Dementia
Understanding quantitative electroencephalography (QEEG) and VR testing.
Posted Oct 04, 2019
Emerging approaches for assessment of cognitive impairment and dementia
This short article is offered as an overview of available conventional approaches used to evaluate the underlying causes of cognitive impairment in individuals complaining of mild memory loss, other cognitive problems, and in individuals with severe cognitive impairment who meet diagnostic criteria for Alzheimer's disease or other forms of dementia. I then briefly review research progress in two innovations that may soon be widely used in the day to day clinical assessment of cognitive impairment: quantitative electroencephalography (QEEG) and virtual reality testing environments.
Conventional approaches used to evaluate cognitive impairment
When evaluating an individual who complains of memory loss, difficulty solving problems, or other symptoms of cognitive impairment, conventionally trained mental health professionals begin with a comprehensive medical, social, and psychiatric history. A thorough history helps to clarify the course, severity, and type of cognitive impairment. If history suggests that severe or persisting cognitive impairment is related to an underlying medical problem the patient is referred to a neurologist for formal evaluation. Functional brain imaging studies such as functional magnetic resonance imaging (fMRI), single photon emission computed tomography (SPECT) or positron emission tomography (PET) scans are done if there is evidence of brain injury, infection, stroke, or a brain tumor. Laboratory studies used to clarify possible underlying physiological causes of cognitive impairment include thyroid studies, complete blood count, liver panel, electrolytes, serum glucose, blood urea nitrogen, and serum vitamin levels. Neuropsychological evaluation using specialized tests of memory, problem solving, and abstract reasoning may clarify the specific type and severity of cognitive impairment.
Limitations of conventional assessment
Although available assessment approaches provide valuable information about the causes of cognitive impairment, they sometimes yield ambiguous findings which pose challenges for clinicians when recommending appropriate treatments. Research is ongoing on technological approaches that may enhance the diagnostic accuracy and reliability of approaches currently used to assess cognitive impairment.
Quantitative electroencephalography (QEEG) and neurometric brain mapping
Quantitative electroencephalography (qEEG) has been the subject of intensive research for many years. Recent findings suggest that qEEG provides superior temporal resolution, is simpler to implement in clinical settings and more affordable than fMRI for analysis of brain network connectivity, and may provide a predictive neuro-marker for the risk of developing Alzheimer’s disease (Stam 2014). QEEG changes that take place at different stages of Alzheimer’s disease and other disorders of severe cognitive impairment reflect decreased regional brain energy metabolism or cerebral blood flow that may not be evident in other imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI). QEEG can be used to reliably differentiate so-called ‘mild cognitive impairment’ (MCI) from Alzheimer’s disease (Kwak 2006).
Neurometric brain mapping is a specialized qEEG approach that compares EEG characteristics of the individual being evaluated with normative databases for healthy individuals of the same age. Neurometric mapping helps to clarify functional brain correlates of cognitive impairment, and yields information that is useful for planning EEG-biofeedback protocols addressing specific kinds of cognitive dysfunction (Surmeli et al 2016). Neurometric brain mapping is being increasingly used in clinical settings to differentiate cognitive impairments that are due to different causes such as head injuries, medical disorders, progressive dementia, alcohol and drug abuse, depressed mood, learning disorders, and other biological causes.
Virtual reality testing environments
Virtual reality (VR) tools are being used to enhance the diagnostic accuracy of existing conventional neuropsychological assessment methods used to evaluate cognitive impairment in degenerative neurological disorders, stroke, developmental disorders, and traumatic brain injury (Montenegro 2017) Virtual performance testing environments are proving to be reliable and accurate for assessment of cognitive impairment and provide a valuable adjunct to conventional neuropsychological testing approaches. Prototype VR environments have yielded promising results for assessment of memory, attention, executive functioning, sensorimotor integration, and many activities of daily living (Allain 2014).
Innovations in Alzheimer's screening tests incorporate immersive virtual environments, concepts from interactive video games, and advanced Human Computer Interaction (HCI) systems. These tests can be used in clinical settings to assess memory loss related to common objects and recent conversations and events, evaluate deficits in expressive and receptive language, and determine an individual’s capacity to differentiate between virtual worlds and reality. VR tests have recently been shown to reliably distinguish healthy individuals from Alzheimer’s patients (Montenegro 2017). A VR testing environment was successfully used to differentiate individuals with mild cognitive impairment (MCI) who were more likely to progress to Alzheimer’s disease from those who were less likely to progress (Tarnanas 2014). The use of VR environments to assess neuropsychological functioning will soon lead to individualized rehabilitation strategies that more effectively address performance deficits on a case by case basis.
Innovations in assessment will lead to more targeted treatment of cognitive impairment and dementia
In the near future, QEEG mapping and VR testing environments will be widely used to enhance currently used assessment approaches of cognitive impairment. Continuing innovations in technology will probably lead to 'combined technologies' that will integrate VR testing platforms with qEEG and functional MRI (fMRI), SPECT and other functional brain-imaging technologies. Together these innovations will advance current understandings of the causes of mild cognitive impairment (MCI) and dementia, resulting in more targeted and more effective treatment.