The irrational behavior may be part of the disease itself or a byproduct of drugs she is taking. My father had PD and had irrational behavior. My mother would distract him from his obsessions; for example, by offering him ice cream, or redirecting his attention somehow.

Punding can be caused by levodopa:

""Punding" is a stereotypical motor behavior in which there is an intense fascination with repetitive handling and examining of mechanical objects, such as picking at oneself or taking apart watches and radios or sorting and arranging of common objects, such as lining up pebbles, rocks, or other small objects.[1] Punding differs from compulsions in that performance of these activities is not distressing to patients and it is only if the act is interrupted that any compulsive urge becomes apparent."

Punding in Parkinson's disease related to high-dose levodopa therapy

http://www.neurologyindia.com/articl...2;aulast=Kumar

"The previously reported cases were women in the age group 65-72 years, similar to our case."

The duration of disease was 10-20 years and they were receiving levodopa at a dose of 500-1900 mg per day, which is similar to our case. Symptoms subsided after decreasing the dose of levodopa in all. Therefore, punding is thought to be related to excessive dopaminergic stimulation.

In conclusion, one should be aware of the possibility of punding in patients with PD on long-term dopaminergic therapy, especially levodopa. As punding is not distressing to the patient, the history may not be volunteered. Failure to recognize this early may be a source of discomfort to the patient and carergivers, whereas early diagnosis can result in prompt relief of symptoms.