Impairment of cognitive memory inhibition in individuals with intellectual disability: A meta-analysis.

BACKGROUND: Cognitive inhibition impairment is intimately related to the forgetfulness of relevant information. This meta-analysis aims to synthesise the evidence of impaired function of cognitive inhibition processes over memory in individuals with intellectual disability (ID). METHOD: Eleven studies were selected and analysed and included a total of 683 participants. The studies were categorised according to variables such as the task used, the processes involved, the sensory modalities and the method. RESULTS: Despite the small sample of studies, the results revealed significant difficulties with cognitive memory inhibition (CMI) tasks in individuals with ID compared with typical development (TD) individuals (d = 0.62). CMI problems were found in all life stages except the 19-45-year-old stage. In this stage, there was a smaller amount of evidence even though it included the 31-40-year-old range, during which premature aging has been observed in ID. CONCLUSIONS: An impairment of CMI in people with ID was observed. More studies are needed to more reliably assess the potential moderating role of age and other factors.

Interference Impacts Working Memory in Mild Cognitive Impairment.

Mild cognitive impairment (MCI) is considered a transitional stage between healthy aging and dementia, specifically Alzheimer's disease (AD). The most common cognitive impairment of MCI includes episodic memory loss and difficulties in working memory (WM). Interference can deplete WM, and an optimal WM performance requires an effective control of attentional resources between the memoranda and the incoming stimuli. Difficulties in handling interference lead to forgetting. However, the interplay between interference and WM in MCI is not well-understood and needs further investigation. The current study investigated the effect of interference during a WM task in 20 MCIs and 20 healthy elder volunteers. Participants performed a delayed match-to-sample paradigm which consisted in two interference conditions, distraction and interruption, and one control condition without any interference. Results evidenced a disproportionate impact of interference on the WM performance of MCIs, mainly in the presence of interruption. These findings demonstrate that interference, and more precisely interruption, is an important proxy for memory-related deficits in MCI. Thus, the current findings reveal novel evidence regarding the causes of WM forgetting in MCI patients, associated with difficulties in the mechanisms of attentional control.