- A diagnostic decision support tool, the Telestroke Mimic Score, is a prediction tool originally derived from patients treated at MGH that distinguished patients with acute cerebrovascular disease from those presenting with stroke mimic. In this study, the score was validated across three independent academic medical centers
- 100%, or all six variables tested that comprise the TM score were found to be substantially different between the patients with cerebrovascular disease vs stroke mimics
- At 33%, a high percentage of patients presenting with stroke-like symptoms did not have an actual ischemic stroke but rather stroke mimic, such as migraine or seizures
As many as 30% of evaluations for suspected acute ischemic stroke turn out to be patients with diagnoses that “mimic” stroke, but are unlikely to benefit from any acute stroke interventions. These “mimics,” such as headaches or seizures, when treated as acute stroke patients result in inappropriate and costly care. To improve diagnostic accuracy for stroke, particularly during telestroke encounters when telecommunication technologies are used in a stroke patient consultation, a Massachusetts General Hospital team developed the Telestroke Mimic Score (TM). Its purpose is to distinguish true acute ischemic cerebrovascular disease from stroke-mimicking symptoms. The TM has been validated within the Partners TeleStroke Network. Lee H. Schwamm, MD, director of Mass General’s Comprehensive Stroke Center, and colleagues led a study that validated the tool at three independent medical center networks.
The team retrospectively evaluated and applied TM scores to over 1930 telestroke consultations that occurred at the University of Utah, Georgia Regents University and the German TeleMedical Project for Integrative Stroke Care Network. Group scores from each hospital, as well as an aggregate score across all hospitals, were compared to those scores from the initial Partners validation study, which found lower TM scores corresponded with a higher likelihood of a stroke mimic.
A TM score for any individual is determined by summing the points assigned for each of the six independent factors as follows:
- Add 0.2 points for every year of age
- Add 6 points if history of atrial fibrillation
- Add 3 points if history of hypertension
- Add 9 points if facial weakness present
- Add 5 points if NIHSS >14
- Subtract 6 points if history of seizure disorder
Published in Stroke, the study found that 32.6% of patients in telestroke consultations were ultimately diagnosed as stroke mimics and all six variables in the TM in both groups were substantially different. A receiver-operating characteristic curve analysis revealed an area under the curve of 0.72 which reflects an acceptable level of predictive power in classifying cerebrovascular disease versus stroke mimics.
As found in previous studies, the stroke mimic group less often had facial weakness, had lower median NIHSS scores and more often a history of seizures.
With the increasing use of telestroke consultations, the TM score can be a helpful decision-support tool. Clinicians can use the simple TM nomogram on a pocket card or software application as a guide towards improved diagnosis when they emergently evaluate patients with symptoms of suspected stroke.