Since developing a developmental screening tool that targets the community, the tool should be perceived simple, cost-efficient, and less time consuming, and most importantly, easy to understand by community health workers and parents. As expounded by Chauhan et al., the tool ought to consider cultural differences and reflect all developmental domains.10
The suggested (EDST), per se, does meet these criteria for early detection of developmental delay of infants at that age. Items of the Indian BDST are simple , applicable and convenient to Egyptian society. On the other hand, children's performance can be detected through the plotting scores of accomplished criteria on the vertical line against their corresponding chronological ages on the horizontal line. Through the50% and 97% age placement passing levels in which the earlier marks the upper curve, while the latter indicates the lower curve, what remains below the curves represents the vulnerable population that requires further investigation for developmental delay (3%).For instance, the 6-month-year old infants could accomplish24 items on the 50% curve, which signpost the number of items passed by 50% of children at this age groups. 97% of the same age expounds 19 items, which, consequently, epitomize specific features characterized by 97% of children at that age group. That determines, therefore, how healthy those infants would be.
Another crucial feature in the Egyptian test lies in the Developmental Age (DA), which is defined by Phataket al. as the age at which 50% of normal children are expected to have identical scores.4 Similarly, the Egyptian model could successfully generate the developmental screening chart by intersecting the horizontal level of scores with the 50% curve. Moreover, Developmental Quotient (DQ) is calculated directly from the EDST chart. The DQ summarizes how well or poor the infant performs in contrast to a large group of infants at the same age.11 To exemplify, if a child from the 12thmonth group scores 23, he/she is shown on the curve as‘ delayed.' 50% of children attained a score of 23 at the 6thmonths their DQ will be calculated as:( DA /CA ) x 100. DQ = 6/12 x 100. DQ = 50%(Figure1).
Additionally, there is a significant difference between the EDST test of infants and the Baroda screening test of infants (BDSI) that were identified via measuring the DA of Egyptian infants in either chart: 50% and 97% passing percentage. Such statistical implication points to the higher versatility of the EDST compared to the BDST to be extensively deployed in Egypt.
Some researchers such as Chunsuwan et al. claimed that using instruments developed mainly for a single culture may not provide the same results in another due to the cultural influence, which is called then a deviant development.12 Nevertheless, other studies have contended the importance of doing more efforts in development of screening tools that respect the local differences.13
However, Western developmental tools (e.g., Bayley scales, and the Denver II) have been primarily designed and validated in Western countries – a fact that might reveal a sort of exclusivity in nature. Even though Gladstone and his colleagues advocated that rendering translations of tests to different languages may bring about misinterpretation of results, as translation may not meet local typicality and culture specificity.14 Likewise, Junejetet.al affirmed that all Western tests have some items that are culturally inappropriate for rural Africa, such as prepares cereal, ‘play board games’ and other uncommon activities.15
Another testing tool that we could have adopted in our study but rejected because of its laborious structure is the Ages & Stages Questionnaire (ASQ) which is a parent report tool widely studied in the West. It is a 19-questionnaire set (30 items per questionnaire) investigating the age range of 2 to 60 months with an overall sensitivity of 75% and specificity of 86%.15
Another study established to validate the Egyptian screening tool by Ages and Stages Questionnaire (ASQ), and the study showed a good correlation of results and approved the Egyptian screening test is valid. The sensitivity is 84.38% and specificity is 98.36 %. The study is under publish eshafie et al 2020 .
A Z-score was developed from our chart facilitates following up infants’ motor and mental developments. In this regard, a child plotted above (-2SD) curve is considered normal, while whoever recognized below -2 SD is deemed developmentally delayed and thus to follow-up his/her progress in further visits. Z-score was calculated for each age group at the following: -3,-2,-1,0,1,2,3 equally in sequence the percentiles (0.13, 2.27 ,15.87 ,50, 84.13 ,97.72 ,99.87 respectively).(Figure 2)