Mild Cognitive Impairment

Overview of MCI

Mild Cognitive Impairment (MCI) encompasses a heterogeneous spectrum of disorders that give rise to subjective complaints of cognitive dysfunction, but these do not disrupt one’s ability to function in everyday life. To diagnose MCI, objective findings of cognitive difficulty must be observed and measured during a patient’s visit to a doctor. Preservation of independent daily function is important, as this distinguishes Mild Cognitive Impairment from other forms of dementia. Many neurological, medical, and psychiatric conditions have to be ruled out before MCI can be considered a risk factor for the eventual development of a dementia.  Factors contributing to development of MCI can include a mood disorder (i.e. anxiety, depression), medication side effects, or medical issues (i.e. vitamin deficiencies, metabolic derangements). The Penn FTD Center performs detailed clinical evaluations to help identify these potentially treatable causes of Mild Cogniitive Impairment.

Symptoms:

MCI can involve one or two cognitive symptoms from the following list: 

·     Episodic Memory involves difficulty encoding, or creating new memories. This can be verbal information, such as recalling a list of words or non-verbal memory, such as recalling a complex geometric design.  Patients may improve in their memory of items with assistance from clues or cues.

·     Visuospatial difficulties, or problems interpreting pictures and understanding their location in space. Individuals  with visuospatial difficulties may have difficulty locating objects in space, understanding complex visual arrays such as a cupboard, constructing objects, and judging distance and speed while driving.  

·     Attention/Concentration, or difficulty maintaining focus on a task. Patients can be distractible or require repetition of instructions for a particular task.

·     Executive Function or the ability to multi-task or switch between one task to another. Patients may feel disorganized or have trouble managing complex tasks such as finances or appointments.  

·     Language or difficulty with expression of language (i.e. word finding) or comprehension of language (i.e. word meaning)

MCI can eventually evolve into a dementia syndrome, such as Alzheimer’s disease. Patients with Mild Cognitive Impairment consisting of largely episodic memory problems (i.e. amnestic-MCI) are often distinguished from those with other cognitive difficulties (i.e. non-amnestic MCI), as amnestic-MCI patients can often progress to develop Alzheimer’s disease. Roughly 10-15% of MCI patients progress to dementia per year. MCI can exist in the setting of other neurodegenerative diseases as well, such as Parkinson’s disease, Frontotemporal degeneration, or Amyotrophic Lateral Sclerosis. However, the development of a form of dementia is not absolute; a percentage of patients can improve to normal cognitive status at repeat testing, or stay in a Mild Cognitive Impairment range of impairment indefinitely. 

Age of Onset & Pathology

Most people with MCI can begin to display symptoms at any age, and symptom onset may be vary. Moreover, the underlying microscopic pathology of MCI is varied.  Most often microscopic evaluation of the brain may reveal Alzheimer’s disease-associated plaques and tangles. MCI can also be associated with other neuropathology findings related to Frontotemporal degeneration , Amyotrophic Lateral Sclerosis, Parkinson’s disease or other neurodegenerative diseases. MCI due to psychiatric or non-degenerative medical causes (i.e. depression, medication side effects) may have normal findings at autopsy.