Cognitive determinants of decisional capacity in neurodegenerative disorders.

OBJECTIVE: Cognitive contributions to decisional capacity are complex and not well understood. Capacity to consent for research has been linked to executive function, but executive function assessment tools are imperfect. In this study, we examine the relationship between decisional capacity and a newly developed executive function composite score and determine whether cognitive performance can predict impaired decisional capacity. METHODS: This is a cross sectional study of participants at the National Institutes of Health with frontotemporal dementia-amyotrophic lateral sclerosis spectrum disorders enrolled between 2017 and 2022. A structured interview tool was used to ascertain research decisional capacity. Study participant Uniform Data Set (v3.0) executive function (UDS3-EF) composite score, Clinical Dementia Rating Scale©, and Neuropsychiatric Inventory was determined. RESULTS: A decrease in UDS3-EF composite score significantly increased the odds of impaired decisional capacity (OR = 2.92, 95% CI [1.66-5.13], p = 0.0002). Executive function was most impaired in frontotemporal dementia (-2.86, SD = 1.26) and least impaired in amyotrophic lateral sclerosis (-0.52, SD = 1.25) participants. The UDS3-EF composite score was also strongly correlated to the Clinical Dementia Rating Scale©. INTERPRETATION: Decisional capacity is intrinsically related to executive function in neurodegenerative disorders, and executive dysfunction may predict a lack of decisional capacity alerting investigators of the need for additional scrutiny during the informed consent process.

The effect of two sites of high frequency vibration on cutaneous pain threshold.

The purpose of this study was to evaluate the effect of two sites of high frequency vibration on experimentally produced pain thresholds. Subjects were assigned to one of two experimental groups. Vibration was applied proximal to the site of pain threshold measurement in one group and distal to the measurement site in the other group. The cutaneous pain threshold was measured at the ulnar aspect of the wrist in both groups prior to, during, and following 5 min of vibration. Subjects were 30 right-handed, Caucasian males with a negative history of upper extremity dysfunction. A repeated measures analysis of variance (ANOVA) was used to analyze the data. There was a significant interaction between vibration site and time of pain threshold measurement. Post hoc analysis of that interaction indicated that a significant difference between experimental groups occurred only during vibration; the distal group values were significantly higher than the proximal group values (P less than 0.03). For the distal group, pain threshold values were significantly higher during vibration than pre vibration and post vibration (P less than 0.05). In the proximal group, there was no significant difference in pain threshold values across the 3 time periods. The results of this study indicate that vibration applied distal to the site of pain can provide temporary analgesia.