Does the ADL part of the unified Parkinson's disease rating scale measure ADL? An evaluation in patients after pallidotomy and thalamic deep brain stimulation.

We evaluated the impact of pallidotomy and thalamic deep brain stimulation (DBS) on disability of patients with advanced Parkinson's disease and investigated whether the activities of daily living (ADL) section of the Unified Parkinson's Disease Rating Scale (UPDRS) measures disability in everyday life. Nineteen patients who had pallidotomy and 14 patients who had thalamic DBS were followed for a mean of 11 months. Evaluation tools included the UPDRS as well as a generic ADL scale, called ADL taxonomy. The 13 items belonging to the ADL part of the UPDRS were classified into two categories according to whether the items described a disability or impairment. The total scores of the UPDRS Part II (ADL) were ameliorated in both the pallidotomy and the thalamic DBS groups. When analysing separately the scores from the two categories of the ADL part of the UPDRS, i.e., disability and impairment, only patients who underwent pallidotomy showed improvement in disability-related items. These findings were confirmed when evaluating the patients with the ADL taxonomy. The ADL part of the UPDRS contains a mixture of impairment- and disability-related items. This mixture may confound results when evaluating the impact of surgery on ADL.