procedural memory

 Procedural memory is a key component of long-term memory that can be assessed in different modalities, such as verbal and motor. Learning through procedural memory occurs in three stages: initial learning, consolidation, and retention. Several tasks evaluate procedural memory, but none have concurrently studied procedural learning in various modalities and learning stages. Besides, according to the declarative-procedural model, there may be an association between the performance of individuals in procedural learning and their state of the grammar of a language. Therefore, this study aimed to design a Serial Search Task (SST) for the simultaneous evaluation of procedural memory in motor and verbal modalities during three stages of learning and determine its reliability. Moreover, the relationship between procedural memory and grammar skills was examined.

 This study is methodological research in the first stage and descriptive analytics in the second stage. First, based on the literature review and the opinions of three speech-language pathologists, some words with appropriate psycholinguistic features were chosen from the Persian picture naming set. Then, corresponding pictures were determined. The task was designed using Java programming language. The face validity of the task was evaluated, then after revisions, the reliability was determined. Face validity was assessed in 10 normal children, and the test-retest reliability was evaluated in 15 normal children aged 7-9 years; all of them were chosen using the convenience sampling method. In the second stage, to assess the relationship between grammatical skills and the SST, 20 normal children aged 7-9 years were selected by a mixed sampling method. Every child had exposed to a verbal modality in three stages: initial learning, consolidation (24 hours later), and retention (one week later). Then the same stages were performed in the motor modality. Each child's language skills were determined using the test of language development-primary (TOLD-P3), and the relationship between the two skills was determined. Statistical methods included the Pearson and Spearman correlation coefficients and repeated measures analysis of variance.

The correlation values between two performances in the initial learning stage for the reaction time variable in verbal (r=0.84, P<0.001) and motor (r=0.80, P˂0.001) modalities and the variable of response accuracy in verbal (r=0.81, P=0.011) and motor (r=0.77, P=0.026) modalities were obtained. In the consolidation and retention stages, the correlation values for the reaction time variable in verbal (r=0.737, P=0.002) and motor (r=0.743, P=0.001) modalities and the variable of response accuracy in verbal (r=0.624, P=0.013) and motor (r=0.916, P<0.001) modalities were obtained. The relationship between grammar and procedural learning in the verbal modality was significant in the consolidation stage (P=0.045, CI:0.016-0.797, r=0.491).

SST is a reliable task to assess different stages of procedural memory in both verbal and motor modalities. Therefore, this task can be used to evaluate procedural memory in normal children aged 7-9 years. The current study's findings confirmed the predictions made by the declarative-procedural model during the consolidation stage in the verbal modality.

According to the Procedural Deficit Hypothesis (PDH) abnormalities in brain structures underlying procedural memory, largely explain language deficits in children with specific language impairment (SLI).The PDH assumes that the procedural memory affects the learning of grammar but the lexical knowledge is not affected. This study aims to examine the procedural memory and its relationship with language skills, in particular with grammar, in children with SLI. Methods and Materials: In this case-control study, We investigated the performance of 9 children with SLI and 9 typically developing children on a number of language and memory tasks. Children with SLI were chosen from speech therapy clinics in Mashhad. The typically developing children selected randomly among kids in a kindergarten. Tools used in this study included Told-P:3, Raven's standard progressive matrices, Expressive One-word Picture Vocabulary Test, Renfrew Action Picture Test, sentence completion subtest from the Wechsler Preschool and Primary Scale of Intelligence (WPPSI), and the Serial Reaction Time task (SRT). To analyze the data, we used the Kolmogorov-Smirnov test. The Pearson Correlation Coefficient was also used to measure the dependence between the variables. This study provides evidence of abnormal procedural memory functioning in children with SLI based on the PDH; however there is no correlation between grammar deficits and abnormal procedural memory in either the SLI (r-value = -0.52, sig. = 0.14) or the control group (r-value = 0.73, sig. =0.73). The results provide mixed support for the PDH. Thus, additional research is required to substantiate the results observed in this study.