Summertime Blues? A Re-Examination of the Seasonality of Web Searches for Restless Legs and Leg Cramps

Publication date: Available online 4 July 2017
Source:Sleep Medicine
Author(s): Shaun T. O'Keeffe
ObjectiveStudies examining internet searches for restless legs and leg cramps have found a strong seasonal effect with peaks in summer and troughs in winter months. This study used an econometric approach to examine the seasonality of such searches in greater detail.MethodsMonthly relative search volumes for “restless legs” and “leg cramps” from 2004 to March 2017 in the United Kingdom (UK) and Australia were obtained from Google Trends. Average percentage change from winter to summer months was examined. The TRAMO-SEATS procedure from DEMETRA statistical software was used to decompose the data into trend, seasonal and noise components and to determine if a combined seasonality test was positive.ResultsThere were substantial percentage increases in Google Trends searches between winter and summer months regarding restless legs in the UK (median increase 46%) and in Australia (33%) and regarding leg cramps in the UK (95%) and in Australia (50%). However, the combined seasonality test was positive only for leg cramps and not for restless legs in both countries: although there was significant stable seasonality in restless legs searches, this was outweighed by substantial moving seasonality and noise components.ConclusionsExamination of average percentage increase in search volume from winter to summer exaggerates the degree of seasonality. Seasonal effects for restless legs searches are non-significant when the trend and noise components of the data are taken into account, although this does not exclude a clinical significance for the identified stable seasonality. Significant seasonality, with a summer peak, is present for leg cramp searches and suggests an increase in the incidence or severity of leg cramps in summer.



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