Spotlight on research from the Memory and Aging Center

The Berkeley Psychophysiology Laboratory directed by Robert Levenson, Ph.D., collaborates with the UCSF Memory and Aging Center to study the emotional functioning of individuals with frontotemporal lobar degeneration (FTLD) and Alzheimer's disease (AD).

FTLD is the umbrella term for frontotemporal dementia, semantic dementia, and primary progressive aphasia. FTLD patients often have problems with social interactions and develop behaviors that are difficult for caregivers and families to manage. One reason for this may be that these patients have trouble understanding emotional cues and social conventions. Patients who do not pick up on emotional and scial signals might not understand that their behavior is inappropriate. To test this notion, the Berkeley Psychophysiology Laboratory has tested emotional responses in over 110 participants. A number of different tasks are used to make participants feel different emotions. For example, they watch emotional film clips and are asked to recall and re-live emotional memories from their past. During these emotional tasks, physiological responses (e.g., heart rate, sweating, breathing), facial displays, and subjective emotional experience are monitored. The following are some of our most recent findings (below):

The Most Basic and Simple Emotional Responding is Preserved in FTLD

As a first step toward understanding how this disease affects emotional functioning, a very simple emotional response was studied. Sudden, unexpected, powerful sensory stimuli elicit a protective startle response at the border of refiex and emotion. FTLD patients and agematched controls are exposed to sudden loud noises while their emotional responses are measured. FTLD patients and controls had comparable startle responses as measured by their physiological responding, emotional facial displays, and self-reported feelings of surprise. This finding indicates the most basic emotional processing and responding remains intact in FTLD patients. This suggests that the emotional effects of the disease may be limited to more complex and more social kinds of emotional responding.

Self-Conscious Emotions (i.e. embarrassment) are Reduced in FTLD

Self-conscious emotions (embarrassment, guilt, pride, shame) are more socially embedded and require a greater appreciation of the thoughts and feelings of other people than simpler emotions (fear and anger). The self-conscious emotions also require a greater awareness of one's own self and behavior. Self-conscious emotions help us behave appropriately in social situations by alerting us as to whether we have done something desirable or undesirable. Many FTLD patients have difficulty in social interactions and do not seem to understand their own emotions nor the emotions of others. This suggests that their self conscious emotions may no longer be working normally. People perform an experimental task while being videotaped, then watch themselves on the videotape to elicit embarrassment. This task produced significant embarrassment in our control subjects, but not in FTLD patients. Specifically, our control participants showed increased physiological arousal, smiling and laughter when watching themselves on videotape. In contrast, FTLD patients showed almost no physiological change and almost no smiling or laughter. This finding supports the idea that there is a loss of self-conscious emotions in FTLD. Because self-conscious emotions require the action of the frontal lobes of the brain (an area that is particularly vulnerable in FTLD), loss of self-conscious emotions could provide an early diagnostic marker of the disease.

There is a Loss of Empathy in FTLD

Empathy for other people is another high-level emotional function that is adversely affected in FTLD. Empathy consists of at least two parts: (1) cognitive empathy-being able to know what someone else is feeling and, (2) emotional empathy-being able to feel what someone else is feeling. We tested whether FTLD patients had an empathetic response to characters in films. We looked both at their ability to identify when a character was feeling (cognitive empathy) and whether they had an emotional response (physiological arousal) to the character (emotional empathy). FTLD patients had deficits in both areas. Compared to control participants, FTLD patients had difficulty identifying the primary emotion the main character was feeling and showed very little physiological arousal when watching the films. FTLD patients had no difficulty describing what was occurring in the film, thus they showed no difficulty in the perceiving and understanding of the specific details of the films. They did not have cognitive or emotional empathy for the film characters. The laboratory is studying why this is the case. One clue came from studying the brain scans of the patients. Those who had suffered the most loss in their anterior temporal lobes had the least empathy.

The Use of Emotional Language is Reduced in FTLD

The Use of Verbal emotional expression is another important part of social communication. The words people use to express their emotions provide important information about what they are and are not feeling. Patients with FTLD often have reduced facial expression of emotions. To determine whether they also have difficulty expressing emotions verbally, conversations between spouses about an area of marital confiict (a very emotional topic for most couples) were examined. After creating verbatim transcripts of the conversations, we counted the number of words participants used within the emotional categories of happiness, sadness, anger, fear, disgust, and surprise. After accounting for the total number of words spoken, FTLD patients used fewer emotion words than control participants. This suggests that FTLD patients do in fact have a deficit in their verbal expression of emotion. Interestingly, during these conversations, FTLD patients had similar levels of physiological arousal to control participants. This suggests that in FTLD, there may be a disconnect between emotional arousal in the body and the verbal expression of emotion.

Conclusions

The work of the Berkeley Psychophysiology Laboratory is providing a better understanding of the social and emotional difficulties in FTLD. FTLD patients appear to retain their very basic emotional functioning (i.e., the startle response), but have deficits with more complex emotions, more social contexts, and when having to make sense of their own emotions and those of others. The frontal and temporal lobes, which are particularly affected by FTLD, are two of the major brain regions that help us to have and manage emotions. Therefore, as these areas deteriorate, patients' emotional capacities are diminished, which interferes with their ability to function in and understand the social world.