Study Notes on Procedural Memory and Grammatical Processing

Procedural Memory and Speed of Grammatical Processing

Article Information

  • Authors: Gillian M. Clark, Jarrad A.G. Lum

  • Institution: Cognitive Neuroscience Unit, School of Psychology, Deakin University, Australia

  • Published In: Research in Developmental Disabilities

  • Date: 23 October 2017

Keywords

  • Procedural memory

  • Specific language impairment

  • Developmental language disorder

Abstract

  • Background: Procedural memory is integral to acquiring grammar, reading, and motor skills. It is theorized that developmental language disorder (DLD) stems from procedural memory issues affecting grammar.

  • Aims: To explore connections between procedural memory and cognitive skills in children with and without language impairments.

  • Methods: Involved 20 children with DLD and 20 age-matched typical developing (TD) children engaging in tasks to assess procedural memory, grammatical processing speed, reading (words and nonwords), and motor skills (pegboard task).

  • Outcomes: No significant correlations between procedural memory and other variables in the DLD group; TD group showed a significant correlation (r = .482, p < .05) between procedural memory and grammatical processing speed but not with reading or motor skills.

  • Conclusions: Grammatical processing speed correlates with procedural memory in TD children, while in DLD, grammar, reading, and motor sequencing appear to rely on different processes.

Introduction

  • Definition of Developmental Language Disorder (DLD): - A neurodevelopmental disorder with expressive and receptive language problems.

    • Not caused by medical conditions or lack of linguistic input (American Psychiatric Association, 2013; World Health Organization, 1992).

  • Co-occurring Issues: DLD often coincides with motor (Hill, 2001) and reading skill deficits (McArthur et al., 2000).

  • Procedural Memory's Role: A body of research links procedural memory problems to language issues in DLD (Nicolson & Fawcett, 2007).

1.1 Procedural Memory in DLD

  • Procedural Deficit Hypothesis (PDH): Proposed by Ullman and Pierpont (2005), suggests dysfunction in the caudate/prefrontal regions leads to procedural memory impairment in DLD.

  • Neural Networks Involved: - Supported by basal ganglia, cerebellum, and cortical structures (Eichenbaum & Cohen, 2004; Graybiel, 1995).

    • Acquires information sequentially, statistically, or through rules.

  • Relation to Grammar: Syntax follows statistical regularities, with acquisition through repeated exposure leading to implicit learning (Ullman, 2001, 2004).

  • Prediction: Individuals with DLD are expected to demonstrate poorer procedural memory than peers without language impairment.

1.2 Associations between Procedural Memory and Grammar

  • Findings: - Correlations between SRTT performance and grammatical skills have been traditionally weak, generally in ranges of .1-.3 (Gabriel et al., 2011; Lum et al., 2012).

    • Some evidence of significant correlation (.48) found in one study (Gabriel et al., 2013).

    • Negative correlations in some studies (e.g., range from -.31 to -.46) suggesting children with DLD performing worse on SRTT might score better on grammar tasks.

  • Hypothesis: Might suggest grammar is process by a different memory system in DLD, potentially compensated by declarative memory (Ullman & Pierpont, 2005).

1.3 Procedural Memory in Reading and Motor Skills

  • Procedural memory disturbances may affect various skills, identified as cortico-striatal for planning/execution and cortico-cerebellar for adaptation/automation (Doyon et al., 2003).

  • DLD Statistics: - 50% of children with DLD also meet dyslexia criteria (McArthur et al., 2000).

    • Motor problems in about 90% of children with DLD (Hill, 2001).

  • Children with reading or motor difficulties tend to perform poorly on SRTT (Gheysen et al., 2011).

1.4 The Current Study

  • Objective: The primary objective of this study was to investigate the specific relationships between procedural memory and key cognitive skills—specifically grammar, reading, and motor functions—in two distinct groups: children diagnosed with Developmental Language Disorder (DLD) and typically developing (TD) children. The study aimed to identify whether these relationships differed between the groups, particularly given the theoretical link between procedural memory deficits and language impairments in DLD. This involved testing two main hypotheses:

    • Hypothesis 1: A correlation of procedural memory with grammatical processing speed would be observed in both groups.

    • Hypothesis 2: Expected correlations would also be present with reading and motor skills across participant groups.

Method
2.1 Participants

  • Forty children participated in the study, forming two groups: 20 children diagnosed with DLD (7 females, 13 males) and 20 age-matched TD children (7 females, 13 males). Their ages ranged from 7 to 11 years.

  • Identification of DLD: Diagnosis of DLD was established using a clinical cutoff score of 85 or below on the Core Language subtests of the Clinical Evaluation of Language Fundamentals - Fourth Edition (CELF-4).

  • Non-verbal Skills: Non-verbal cognitive abilities were assessed using either the Wechsler Abbreviated Scale of Intelligence (WASI) Matrix Reasoning subtest or Raven’s Coloured Progressive Matrices to ensure comparable non-verbal intellectual capacity between groups.

2.2 Materials

A comprehensive battery of tasks was administered to assess specific cognitive domains:

2.2.1 Procedural Memory (SRTT)

  • Evaluated using a Serial Reaction Time Task (SRTT). Participants were instructed to press buttons corresponding to the location of visual stimuli (a cartoon picture of a fly) presented on a screen. The task involved following a hidden sequence of stimuli.

  • Block Designs: The protocol included Blocks 1-3, which involved a repeating, hidden sequence, and Block 4, which presented stimuli in a random order. Procedural learning was measured by assessing the difference in reaction time between Block 3 (sequential learning) and Block 4 (random presentation).

2.2.2 Grammatical Processing Speed

  • Measured via a sentence comprehension task. This task involved auditory stimuli (spoken sentences) presented concurrently with visual stimuli (multiple pictures).

  • Task: Participants were required to quickly and accurately select the correct image that matched the presented sentence. Reaction times for correct responses were meticulously measured as the primary indicator of grammatical processing speed.

2.2.3 Control Task: Word Recognition

  • A word-picture matching task was included. This task served as a control to account for basic processing influences that might affect performance on the more complex comprehension tasks, ensuring that observed differences were not solely due to fundamental word recognition abilities.

2.2.4 Reading Skills

  • Assessed using the Test of Word Reading Efficiency (TOWRE). This standardized test measured both the accuracy and efficiency of reading processes by requiring participants to read isolated words and nonwords under timed conditions.

2.2.5 Motor Skills

  • Purdue Pegboard Task: This task was employed to measure fine motor control, manual dexterity, and sequencing capacities. Participants were required to place small pegs into holes as quickly and accurately as possible, providing an assessment of motor function.

2.3 Procedure

  • All testing sessions were conducted individually for each child to minimize distractions and ensure standardized administration. The extensive battery of tasks, covering procedural memory, grammatical processing speed, reading, and motor skills, was distributed across multiple sessions to prevent participant fatigue and optimize performance. Prior to each specific task, detailed instructions were provided, and practice trials were conducted to ensure that all participants fully understood the requirements before formal data collection began. Reaction times were precisely recorded for all timed tasks to accurately capture processing speed.

Results
3.1 Performance Comparison

  • Group Differences: DLD children showed poorer performance on SRTT and reading tasks but not significant differences in sentence comprehension accuracy.

3.2 Correlations and Analyses

  • TD Group Findings: Significant negative correlations observed between SRTT and grammatical skills; no correlations with reading/motor tasks.

  • DLD Group Findings: Lack of significant correlation between all tasks, indicating procedural memory is not linked to grammatical processing, reading, or motor skills.

Discussion

  • Findings Summary: Procedure memory's speed correlates with speed of grammatical processing in TD children but not DLD.- Recommends future grammar measures focus on processing speed rather than accuracy.

  • Implications for DLD Group: Procedural memory appears not to be associated with grammar, suggesting potential compensation by declarative memory or different processing systems altogether.

Conclusions

  • Procedural memory relates to grammatical efficiency in TD children, yet in DLD, it does not correlate with measured skills, indicating the necessity for further investigation into compensatory processes in developmental disorders.

Appendix
References

  • Comprehensive references list provided, including key studies by Ullman, Nicolson, and others indicating relationships and implications of procedural memory in various contexts.