Revisiting the Examination of Sharp/Dull Discrimination as Clinical Measure of Spinothalamic Tract Integrity

Objective: Revisiting the sharp/dull discrimination as clinical measure of spinothalamic tract function considering the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). Three clinically relevant factors were evaluated as to their impact on reliability: (1) the localization of dermatomes in relation to the sensory level, (2) the examination tool, and (3) the threshold of correct answers for grading of a preserved sharp/dull discrimination.Design: Prospective monocentric psychometric study.Setting: Spinal Cord Injury Center, Heidelberg University Hospital, Germany.Participants: Convenient sample of 21 individuals with subacute spinal cord injury (age: 31–82 years) and 20 individuals without spinal cord injury (age: 24–63 years).Assessment: All participants underwent three assessments for sharp/dull discrimination, applying five commonly used examination tools in seven dermatomes, performed by three trained examiners under conditions in accordance with ISNCSCI.Main Outcome Measures: Assessment of interrater reliability by determining both the Fleiss kappa (κ) coefficient and the percentage agreement between raters. Data were dichotomized regarding the ISNCSCI threshold.Results: Interrater reliability in individuals with SCI was overall substantial (κ = 0.68; CI 0.679–0.681) and moderate (κ = 0.54; CI 0.539–0.543) in dermatomes below the sensory level. All applied tools led to at least moderate reliability below the sensory level (lowest κ = 0.44; CI 0.432–0.440), with the officially endorsed safety pin achieving the highest (substantial) reliability (κ = 0.64; CI 0.638–0.646). Percentage agreement differed between non-SCI (97.3%) and formally intact above level dermatomes in SCI (89.2%).Conclusions: Sharp/dull discrimination as a common clinical examination technique for spinothalamic tract function is a reliable assessment. Independent from the used examination tools, reliability was substantial, with the medium-sized safety pin delivering the most favorable results. Notwithstanding this, all other tools could be considered if a safety pin is not available. Regarding interrater reliability and guessing probability, a threshold of 80% correct responses for preserved sharp/dull discrimination appears to be most suitable, which is in line with current clinical approaches and ISNCSCI. The causal attribution of the identified differences in sharp/dull discrimination between clinically intact dermatomes of individuals with SCI and unaffected dermatomes of individuals without SCI requires future work.Clinical Trial Registration Number (German Clinical Trials Register): DRKS00015334 (https://www.drks.de).

Using Item 8 of the Abnormal Involuntary Movement Scale (AIMS) to Assess Improvement in Patients with Tardive Dyskinesia

ObjectiveThe Abnormal Involuntary Movement Scale (AIMS) total score (sum of items 1–7) is usually the primary efficacy measure in tardive dyskinesia (TD) clinical trials. However, item 8 of the AIMS (clinician’s global impression of severity) might also be an appropriate assessment in real-life healthcare settings. To explore the potential of item 8 as a clinical measure, post hoc analyses were conducted using data from a long-term study of valbenazine, an approved TD medication.MethodsIn KINECT 4 (NCT02405091), adults with TD received once-daily valbenazine (40 or 80 mg) for 48 weeks. Analyses included two sets of AIMS item 8 scores: based on investigators ratings of item 8 using protocol-defined descriptors; and based on investigators highest scores from items 1–7 (analyzed post hoc). Shift analyses included an improvement from score =3 at baseline (moderate or severe) to score =2 at Week 48 (none to mild).ResultsAt baseline in all participants (N=163), AIMS item 8 mean scores were 3.2 (protocol) and 3.3 (post hoc). In participants with a score =3 at baseline per investigators ratings using protocol-defined descriptors, 95.9% [94/98] shifted to a score =2 by Week 48. A similar result (93.9% [93/99]) was found when item 8 was based on investigators highest scores from items 1–7.ConclusionShift analyses using AIMS item 8 scores indicated that most participants in KINECT 4 had a clinically meaningful improvement after 48 weeks of once-daily treatment with valbenazine. AIMS item 8 may be an appropriate clinical measure for assessing changes in TD severity.FundingNeurocrine Biosciences, Inc.