For refractory cases of severe PD tremor, stereotactic thalamotomy is an effective option. All things being equal, bradykinesia severe enough to cause marked slowing in walking and handling utensils is more likely to result in disability in someone who is working than someone who is not. Patients with PD who are working have to perform under a more strict time frame, and their symptoms can impair job performance. The ADL scale evaluates speech, salivation, swallowing, handwriting, cutting food, handling utensils, hygiene, tuning in bed, falling, freezing, walking, tremor, and sensory symptoms. Careful questioning with the ADL scale as a framework often provide insight into how particular symptoms result in disability and provides a means of monitoring Parkinsonism over time.
Cognitive impairment is an important modifier in determining pharmacologic intervention.
Overt or subclinical cognitive impairment can alter a patient's response to antiparkinsonian drugs, especially anticholinergics and amantadine. In these patients, pharmacologic intervention can superimpose a toxic delirium on a substrate of disease related impairment. Cognitive impairment also can affect pharmacologic intervention indirectly. Patients with cognitive impairment may not perceive symptoms as acutely as patients without it. Such patients, although functionally impaired, sometimes insist they require no treatment.