Competency is a legal term, defined as: “duly qualified: having sufficient capacity, ability, or authority” (Black’s Law Dictionary).

A question of competence may arise in such matters as wills, trusts, contracts, prenuptial agreements, health care decisions, and conservatorship proceedings. 


In Alzheimer’s disease or related dementias, someone with mild illness may not present with intellectual impairments and there may be supportive friends or family who respond for the individual, thus obscuring deficits. In addition, many people with dementia retain an appearance of physical well-being and are quite sociable, therefore giving a false impression of normal cognitive function.


Mental Capacity is a functional term that may be defined as: the “mental (or cognitive) ability to understand the nature and effects of one’s acts.” The term capacity is frequently mistaken for competency. Capacity is determined by a physician and not the judiciary. Capacity refers to an assessment of the individual’s psychological abilities to form rational decisions, specifically the individual’s ability to understand, appreciate, and manipulate information and form rational decisions.


Capacity involves the use of executive functions such as:

  • Initiation
  • Analysis
  • Anticipating consequences
  • Anticipating secondary effects
  • Planning to avoid problems
  • Organizing
  • Prioritizing
  • Pacing

These executive functions become compromised early on in the disease. The person begins to lose the ability to consistently use these functions. The individual’s ability to clearly understand his/her deficits becomes diminished. The person begins to lose the ability to clearly understand the consequences or risks of his or her actions.


Authors of functional assessments such as Barry Reisberg, M.D. and Claudia Allen, MA, OTR have documented common patterns of functional performance that correlate to the symptom progression. The functional assessment scales describe patterns of behavior that are observed at different stages of dementia. These staging systems provide frames of reference for understanding how the disease may unfold and for making future plans.


Functional assessment uses information derived from observed behaviors to pinpoint areas of cognitive impairment. These assessments are administered by observing functional performance and through interview of the client and caregiver. These assessments and scales can help the health care professional and the attorney determine whether a client is impaired and in need of a clinical evaluation regarding mental capacity.


The following are descriptions of the abilities and deficits that impact mental capacity when a person is performing at Allen Cognitive Levels, 5-, 4+ and 4-


Capacity and Stages of Dementia


FAST stage 3, Allen level 5-
This stage is not classified as a stage of dementia, but is often named Mild Cognitive Impairment. The main concern with this impairment is that the individual has lost the ability to clearly understand the secondary effects of his/her actions. For example, the person may appoint someone as POA for finances with the understanding that the POA will assist in the future as needed. However, the person may not consider how this decision may impact other family members, or the person may not consider the ability of the POA to make good financial decisions that are in the client’s best interest.


Persons with this mild impairment do have the ability to learn and understand the secondary effects, but this person does not have the ability to consider these effects without assistance. In addition, the person does not generalize learning easily from one situation to another. Therefore, similar explanations must be provided for every situation (e.g., naming a health surrogate).


At this very early stage, driving becomes a concern because of this lack of ability to clearly understand secondary effects. The person can perform the mechanics to drive the car safely and travel to new locations; however, the person no longer considers how the driving impacts other people on the road.


FAST stage 4, Allen level 4+
This stage is comparable to the early part of Early Stage dementia. Persons performing at this stage continue to complete basic daily tasks independently and safely, and the ability to communicate is intact. Therefore, this person often fools the professional (including physicians), in the brief interviews in the office.


At this stage, the executive skills are obviously compromised. The person lacks the capacity to plan ahead, prioritize, or organize efficiently. This becomes very evident in financial transactions.


Because routine daily tasks are the person’s strength, he/she may continue to pay each bill that comes in the mail as part of a routine. However, if there is any change in the billing method, or if an additional bill is added, the person may ignore it. Or the person may pay bills more than once, or pay for an insurance statement that states “this is not a bill.” The decline in ability to make accurate calculations will be evident in the checkbook.


This is the person who will resist any changes in investment strategies. What makes sense and feels safe to this client is what he/she always did in the past. The client will not be able to fully understand a need for change.


In addition, the person will have problems with reading comprehension due to the decline in short-term memory. Because of these deficits, the client will have difficulty reading and fully understanding contracts. He/she will miss part of the information and this will lead to an inability to understand the entire document.


Persons performing at this stage require supervision or assistance for all higher level daily activities that require the executive skills. This person no longer has the capacity to clearly understand the consequences of his/her decisions in these areas. 


FAST stage 5, Allen level 4-
This stage is comparable to the end of the Early Stage of dementia. The person is able to complete basic daily tasks independently, but needs assistance for quality. The person requires 24-hour supervision to insure safety and adequate completion of basic tasks.


The client presents with poor short-term memory leading to poor judgment and poor problem-solving abilities. The client will have difficulty managing simple money transactions, and will be dependent on others to manage finances. 


Reading comprehension is poor. The person will have difficulty remembering what is in one paragraph compared to the next; therefore, the client will not be able to understand a new contract or document.


The person may be able to engage in conversation about topics that are stored in the long-term memory (including facts related to a profession as a lawyer, engineer, or accountant). When this occurs, an evaluator may conclude that the person’s cognition fluctuates and the person may have increased capacity at times. This conclusion may be dangerous for the client. Long-term memory is a strength, and the person will demonstrate this when he/she is asked to tap into that memory in conversation about past knowledge. However, when presented with a new problem or asked to learn a new task, or remember what was just said or read, the person’s poor short-term memory will be evident.


In addition, the person is often unaware of memory deficits and therefore may be resistant to accepting assistance.


As people live longer due to the advancement of medical technology, the percentage of persons with dementia will rise. Alzheimer’s disease is now being considered an epidemic. It is imperative that we do not ignore the signs. 


With the use of functional assessments, we are in a position to be able to recognize the problems, provide the necessary assistance to help the client complete needed documents or transactions (with caregiver involvement as needed), and provide appropriate referrals to insure our client’s quality of life.



The Alzheimer’s Association.

Allen, C.K., Earhart, C.A., and Blue, T. (1992) Occupational Therapy Treatment Goals for the Physically and Cognitively Disabled. Bethesda, MD: American Occupational Therapy Association

Black, HC Black’s Law Dictionary, 5th ed. St. Paul, Minn: West Publishing Company; 1979:257.

Geriatric Resources

Leo, Raphael J. Competency and the Capacity to Make Treatment Decisions: A Primer for Primary Care Physicians. J Clin Psychiatry1999;1:5

Reisberg, B, Franssen EG, Souren LEM, Auer SR, Akram I, Kenowsky S. Evidence and mechanisms of Retrogenesis in Alzheimer’s and other dementias: management and treatment . Am J Alzheimer’s Dis. 2002;17(4):202-212

Shenk, David, The Forgetting Alzheimer’s: Portrait of an Epidemic, Doubleday: New York, 2001.

Warchol, K., Ebell, C., Copeland, C., Dementia Therapy: Achieving Positive Outcomes for the Person with Dementia, Live Course Manual, 2008.