Up to 30% of self-reported cases of essential tremors might be incorrectly classified, according to a recent study published in the Journal of the Neurological Sciences.
The researchers of this study evaluated the validity of self-reports and relative reports of essential tremors for use in future genetic trend investigations. They recruited patients diagnosed with essential tremors (n=98) and their relatives (n=243). The first contact with the patient was a telephone interview, during which researchers obtained general information about the relatives. Next was an in-home interview with both the patient and the relatives. The main focus was neck, jaw, and voice tremors, but other postural, kinetic, intention, and rest tremors were noted. Diagnoses were based on questionnaires and neurological examinations. All tremors were evaluated using published diagnostic criteria proven valid internationally.
The patients described 54.3% of their relatives as having tremors, but 90.9% of their relatives self-reported having tremors, and 65.4% of their relatives received a final diagnosis of tremors. Of the 139 relatives with tremors, probands incorrectly reported 39 as not having tremors; of the 104 relatives without tremors, probands incorrectly reported 32 as having tremors. The rate of misidentification was 29.2%. Of the 139 relatives with tremors, relatives incorrectly self-reported 36 times as not having tremors; of the 104 relatives without tremors, relatives incorrectly self-reported 30 times as having tremors, for a misidentification rate of 27.2%. In both the patients’ and relatives’ reports, there was a higher mean neurological examination tremor score in the true positives than the false negatives, and 63.2% of false negatives had head tremors. This current study had a higher reported validity than previous studies, possibly due to a higher level of education and the patients’ increased knowledge of essential tremor disease. These findings are beneficial to other researchers who study the relationship between essential tremors and the genetic code, as they rely heavily on self-reported data.
Future studies need to evaluate a larger sample size with a more diverse background to detect characteristics that might influence the accuracy of self-reporting tremors.
Researchers conclude that 1 in 3 self-reported essential tremors, whether reported by the patient or a relative, prove to be incorrect. This is important information to be aware of when research relies on this data.
This study was supported by National Institutes of Health.
Louis ED, Hernandez N, Sebastian AA, Clark LN, Ottman R. Validity of probands’ reports and self-reports of essential tremor: Data from a large family study in North America. J Neurol Sci. 2018; 393:45-50.