A Response to: Human Fall Detection Using Passive Infrared Sensors with Low Resolution: A Systematic Review [Letter].

Dear editor

We have read with great interest the paper entitled “Human Fall Detection Using Passive Infrared Sensors with Low Resolution: A Systematic Review” by Ben-Sadoun et al.1 This systematic review was designed and conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA, version 2020).2 The goal of this review was to identify studies that investigated the metrological qualities of passive infrared sensors with a very low resolution to identify falls or related conditions (eg, lying on the floor).1

However, two points need to be mentioned for the readers.

This protocol has not been registered in any international database of prospectively registered systematic reviews. It is recommended that the protocol be registered in the PROSPERO database to be reviewed by peers and to reduce unnecessary duplication of effort among researchers. If the review protocol has been registered, it must be indicated where it is accessible by providing the registration number and website address or using someone else’s protocol.3 PROSPERO is an international database of prospectively registered systematic reviews in health and social affairs.4 The main features of the review protocol are recorded and maintained as a permanent record. Systematic reviews should be registered at the outset (ie, at the protocol stage) to help avoid unplanned duplication and to allow comparison of the reported review methods with those planned in the protocol.5

At the articles selection process stage, there are difficulties for readers to understand the PRISMA diagram shown. In the final stage of the PRISMA diagram, four articles were excluded because the four authors “duplicated” their study in two different journals, so there are 15 articles included in the analysis. However, Table 1 (Studies Characteristics Regarding Their Sensors Used, Experimental Procedures, Detection Methods, and Detection Performance) and Figure 2 (Publication dates of studies) still include 19 articles. The author should not include the four articles that have been excluded.