The aging population in the U.S. is growing rapidly. The number of people aged 65 and above was 40.2 million in 2010 and is expected to double by 2050. As the population of older adults in the United States expands, studies report that an increasing number are affected by cognitive impairment. Recognizing, diagnosing, and documenting the various types of cognitive impairment is a challenging task for physicians. Clear and precise medical record documentation is necessary for accurate coding and sequencing for cognitive disorders. With proper documentation, medical billing companies can help physicians select the correct ICD-10 codes and file clean claims for appropriate reimbursement.

Cognitive Disorder – Symptoms and Causes

The term cognitive disorder refers to any type of disorder, disease, or condition that affects a person’s cognitive functioning. This results in the person having trouble remembering, concentrating, learning new things, or making decisions that affect their everyday life. This can be a temporary problem or a permanent condition and range from mild to severe.

Cognitive impairment generally means some kind of problem or difficulty with the following things:

  • Various mental functions such as learning and memory
  • Recognizing or identifying and understanding the relationships of objects in one’s environment
  • Solving problems or exercising judgment in an emergency situation
  • Understanding language
  • Communicating with others
  • Making decisions
  • Recognizing familiar people and places
  • Planning and carrying out tasks such as keeping track of monthly bills
  • Dealing with new places or situations

Deterioration in emotional control, speech, social behavior, motivation or ability to perform daily tasks may accompany or precede cognitive deterioration. Age is the biggest risk factor for cognitive impairment. Other risk factors include family history, education level, brain injury, exposure to pesticides or toxins, physical inactivity, and chronic conditions such as Parkinson’s disease, heart disease and stroke, and diabetes.

Five Common Age-related Cognitive Disorders and Associated ICD-10 Codes

  1. Mild cognitive impairment: Mayo Clinic defines mild cognitive impairment as “the stage between the expected cognitive decline of normal aging and the more serious decline of dementia”. This condition affects memory, language, thinking and judgment, but not at a level which impairs daily functioning as Alzheimer’s disease does. Mild cognitive impairment may remain stable for years or improve over time. Research suggests that 10 to 15 percent cases of mild cognitive impairment progress into dementia each year. The ICD-10 code to specify a diagnosis of mild cognitive impairment is:
    G31.84 Mild cognitive impairment, so stated
  2. Alzheimer’s disease: Alzheimer’s is the most common dementia. The Alzheimer’s Association estimates that 5.8 million Americans of all ages were living with Alzheimer’s dementia in 2019. Of this number, about 5.6 million are people age 65 and older and approximately 200,000 individuals are under age 65.
  3. ICD-10-CM offers four options to code the condition:

    • G30.0 – Alzheimer’s disease with early onset
    • G30.1 – Alzheimer’s disease with late onset
    • G30.9 – Other Alzheimer’s disease
    • G30.9 – Alzheimer’s disease, unspecified

    Based on the physician’s documentation, codes G30.0 and G30.1 can be used to report the condition to highest level of specificity. Category G30 instructs using an additional code to identify delirium, if present:

    • F02.80 Dementia without behavioral disturbance
    • F02.81 Dementia with behavioral disturbance

    The ICD-10 Alphabetic Index instructs reporting Alzheimer’s with behavioral disturbance as: G30.9 (F02.81).

  4. Parkinson’s disease: Approximately 60,000 Americans are diagnosed with Parkinson’s disease each year. Symptoms of this progressive neurological disorder include muscle rigidity, tremors, and changes in speech and gait. The National Parkinson Foundation identifies the common cognitive issues people living with Parkinson’s disease as: slowness of thinking, difficulty concentrating and with problem solving, lack of reasoning skills, brain fog, and language and memory problems.

    A 2019 ACP Hospitalist article notes that up to 40% of cases are considered as being associated with Parkinson’s dementia, and the term Parkinsonism is used to describe Parkinson’s disease without dementia. There are several ICD-10 codes for reporting diagnosis of Parkinson’s disease. Additional codes must be used for Parkinson’s disease with dementia and with or without behavior disorder:

    • G20 Parkinson’s disease, primary without dementia
    • G31.83 (F02.80) With dementia without behavior disorder
    • G31.83 (F02.81) With dementia and behavior disorder

  5. Lewy body dementia (or dementia with Lewy bodies): This dementia type is caused by abnormal clumps of proteins in the brain called Lewy bodies. These clumps are also present with Parkinson’s disease. The ICD-10 code for Lewy body dementia falls under section G31, titled “Other degenerative diseases of nervous system, not elsewhere classified:
    • G31.83 Dementia with Lewy Bodies

    Additional codes should be used to indicate behavioral disturbance. Code G31.83 is also used to identify the following:
    Dementia with Parkinsonism and Lewy body disease
    An ICD-10 Monitor article points out that G31.83 groups to a two-tiered MS-DRG:

    • MS-DRG 056: Degenerative nervous system disorders with MCC, or
    • MS-DRG 057: Degenerative nervous system disorders without MCC

    Patients with the disease show varying symptoms, though most experience a decline in cognition in conjunction with movement difficulties as is found in Parkinson’s disease is common. The documentation should specify any behavior that a clinician considers a behavioral disorder. The physician’s documentation is critical for correct coding and sequencing for Lewy body dementia.

  6. Behavioral variant frontotemporal dementia: This condition is caused by damage to the frontal or temporal lobes of the brain. Studies have found that late onset forms account for up to 40% of all cases and is usually accompanied by behavioral disturbances andpersonality changes associated with deterioration of the language skills, stubbornness, apathy and reduced inhibition, and lack of insight. The ICD-10 codes to report the disease are:
    • G31.0 Frontotemporal dementia
    • G31.09 – Other frontotemporal dementia

Correct code assignment to the highest level of specificity depends on precise documentation, and is crucial to fully describe the patient’s condition and severity of illness. Behavioral disturbances such as psychotic symptoms, mood disturbance, agitation, apathy, aggression, combativeness, and “wandering off” should be identified and documented as a behavioral disturbance (www.acphospitalist.org). The underlying physiological condition or sequelae of cerebrovascular disease should always be documented when known. If the documentation is unclear, contradictory or vague, the coding team in a reliable medical billing and coding company will query the physician to identify the specific condition and assign the right code.