This 52-year-old left-handed woman with a 10-year history of multiple sclerosis (MS) developed fluctuating affect over the last year. Her children described she cried or laughed inappropriately, without a clear trigger. These episodes lasted less than 10 minutes. Even in the occasions where there was an emotion-triggering event, the response (crying or laughing) was disproportionate and contrary to the expectations (i.e., laughing at something sad). These episodes of laughter and crying were beyond her control and lasted a couple of minutes. Although the patient endorsed being frustrated about these episodes, and endorsed fatigue and slowness in her thinking, she denied persistence in feeling sad, lacking interests or thinking about death. On exam, she exhibited a spastic-ataxic speech and generalized ataxia with spasticity in her upper extremities. Her Beck Depression Inventory (BDI) score was 11, meeting threshold for mild mood disturbance (discouraged about the future, not enjoying things, feeling disappointed about her life, crying more, being more irritable, taking longer to make decisions, being concerned about her looks, needing extra effort to do things, difficulties sleeping, and being worried about her health).