Emotions & Behavior

Emotional and behavioral symptoms are common in dementia and can be major sources of stress to patients and their caregivers. Some of the most common emotional and behavioral changes associated with dementia are:

• Apathy and Indifference — lack of motivation to start new activities and continue old ones, reduced participation in household chores, loss of interest in talking to other people, becoming less affectionate and emotionally expressive.
• Depression and Dysphoria — tearfulness and crying, consistently low mood, feelings of failure, despair about the future, suicidal thoughts and actions.
• Disinhibition — acting impulsively without thinking, saying or doing things not usually done or said in public, doing things that are embarrassing to others.
• Euphoria and Elation — inappropriate giggling and laughter, playing childish games, feeling excessively good for no apparent reason, making false claims about one’s abilities or wealth.
• Anxiety — being nervous or worried for no reason, avoiding situations that cause nervousness, tenseness or shortness of breath with no other explanation.
• Irritability and Lability — increased temper, crankiness, rapid mood changes.
• Agitation and Aggression — resisting those trying to help, refusing to cooperate, stubbornness, yelling, hitting.
• Eating Disorders — changes in weight (gain or loss), changes in appetite, changes in appropriate eating behavior, preferences for only certain types of foods.
• Sleep Disturbances — difficulty falling asleep or staying asleep, wandering or pacing in the middle of the night, getting up and getting dressed.
• Aberrant Motor Behaviors — repetitive behaviors such as opening and closing doors or drawers, repeatedly picking at things, pacing back and forth.
• Hallucinations — seeing or hearing things that do not exist.
• Delusions — holding false beliefs, such as thinking family members are not who they say they are, that others intend one harm, or that one’s home is not his/her home.

Anatomy of Emotion and Behavior
Emotional and behavioral symptoms are thought to be caused by damage to specific areas of the brain that are responsible for directing our attention, motivating our behavior, and learning the significance of what is going on around us. Pioneering work by Papez (1937) originally suggested that emotion is related to a ring of structures in the center of the brain called the limbic system. This ring includes the hypothalamus, anterior thalamic nuclei, cingulate cortex, and hippocampus. More recent research has shown that some of these structures are not as directly related to emotion as others, while additional structures have also been added to the list. The following brain structures are currently thought to be most involved in emotion and behavior:

• Amygdala — The amygdalae are two small round structures located near the anterior (front) end of the temporal lobes. The amygdalae are involved in detecting and learning what parts of our surroundings are important and have emotional significance. They are critical for the production of emotion and may be particularly important for the generation of negative emotions, especially fear.
• Prefrontal Cortex — The term prefrontal cortex refers to the very front part of the brain located behind the forehead and above the eyes. It appears to play a critical role in the regulation of emotion and behavior by anticipating the consequences of our actions. The prefrontal cortex may play an important role in delayed gratification by maintaining emotions over time and organizing our behavior toward specific goals.
• Anterior Cingulate — The anterior cingulate cortex (ACC) is located in the middle of the brain just behind the prefrontal cortex. The ACC is thought to play a central role in attention, and may be particularly important with regard to one’s conscious subjective emotional awareness. This region of the brain may also play an important role in the initiation of motivated behavior.
• Ventral Striatum — The ventral striatum refers to a group of subcortical structures thought to play an important role in emotion and behavior. One part of the ventral striatum called the nucleus accumbens is thought to be involved in the experience of goal-directed positive emotion. Individuals with addictions, for example, experience increased activity in this area when they encounter the object of their addiction.
• Insula — The insular cortex is thought to play a critical role in the bodily experience of emotion, as it is connected to other brain structures that regulate the body’s autonomic functions (heart rate, breathing, digestion, etc.). This region also processes taste information and is thought to play an important role in experiencing the emotion of disgust.

Impact of Neurologic Illness on Emotion and Behavior
Neurologic disorders result in different patterns of emotional and behavioral changes depending on what parts of the brain are affected. In Frontotemporal Dementia, behavioral and emotional changes are often dramatic and form the core clinical features of the disorder. In other disorders, behavioral and emotional changes may occur, but are often less common or less severe.

• Frontotemporal Dementia (FTD) — FTD is associated with atrophy of the prefrontal cortex, anterior cingulate, insula, and ventral striatum. When this atrophy is predominantly right-sided, FTD is almost always associated with changes in behavioral and emotional function. The changes most commonly associated with FTD are apathy, disinhibition, aberrant motor behaviors, and eating disorders (specifically increases in appetite and strong preferences for sweets or other particular foods). Other behavioral changes in FTD include elation and euphoria, aggression, irritability, sleep disturbances, depression, and anxiety. Sometimes patients with FTD also develop addictive behaviors late in life.
• Semantic Dementia (SD) — SD results from atrophy of the anterior temporal lobes (including the amygdala), insula, prefrontal cortex, and anterior cingulate. Though more commonly thought of as a language disorder, SD is often associated with dramatic changes in behavioral and emotional function. Disinhibition and compulsive behaviors are the most common changes in SD. Other common changes include apathy, eating disorders, sleep disturbances, elation and euphoria, as well as depression, anxiety, irritability, and aggression.
• Alzheimer's Disease (AD) — The behavioral and emotional changes seen in AD, on average, are less severe than those that occur in FTD and SD particularly in the early stages. The most common behavioral change associated with AD is apathy. Also common in AD are irritability, agitation, depression, anxiety, sleep disturbances, and eating disorders (especially a decreased appetite and loss of weight).
• Dementia with Lewy Bodies (DLB) — DLB may be associated with many of the same changes seen in AD. DLB is often associated with vivid hallucinations (such as small children or animals).
• Other Disorders — Behavioral and emotional changes are less common or less severe in disorders such as Corticobasal Degeneration (CBD), Progressive Supranuclear Palsy (PSP), and Primary Progressive Aphasia (PPA).

References

• Cummings JL. “The Neuropsychiatric Inventory: assessing psychopathology in dementia patients.” Neurology. 1997;48:S10-6.
• Davidson RJ, Irwin W. “The functional neuroanatomy of emotion and affective style.” Trends in Cognitive Science. 1999;3:11-21.
• Dalgleish T. The emotional brain. Nature Reviews Neuroscience 2004;5:583-9.
• Papez JW. A proposed mechanism of emotion. Journal of Neuropsychiatry and Clinical Neuroscience. 1937;7:103-12.
• Rosen HJ, Gorno-Tempini ML, Goldman WP, Perry RJ, Schuff N, Weiner M, Feiwell R, Kramer JH, Miller BL. Patterns of brain atrophy in frontotemporal dementia and semantic dementia. Neurology. 2002;58:198-208.

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