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Zemla JC, Gooding DC, Austerweil JL. Evidence for optimal semantic search throughout adulthood. Sci Rep 2023; 13:22528. [PMID: 38110643 PMCID: PMC10728182 DOI: 10.1038/s41598-023-49858-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 12/12/2023] [Indexed: 12/20/2023] Open
Abstract
As people age, they learn and store new knowledge in their semantic memory. Despite learning a tremendous amount of information, people can still recall information relevant to the current situation with ease. To accomplish this, the mind must efficiently organize and search a vast store of information. It also must continue to retrieve information effectively despite changes in cognitive mechanisms due to healthy aging, including a general slowing in information processing and a decline in executive functioning. How effectively does the mind of an individual adjust its search to account for changes due to aging? We tested 746 people ages 25 through 69 on a semantic fluency task (free listing animals) and found that, on average, retrieval follows an optimal path through semantic memory. Participants tended to list a sequence of semantically related animals (e.g., lion, tiger, puma) before switching to a semantically unrelated animal (e.g., whale). We found that the timing of these transitions to semantically unrelated animals was remarkably consistent with an optimal strategy for maximizing the overall rate of retrieval (i.e., the number of animals listed per unit time). Age did not affect an individual's deviation from the optimal strategy given their general performance, suggesting that people adapt and continue to search memory optimally throughout their lives. We argue that this result is more likely due to compensating for a general slowing than a decline in executive functioning.
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Affiliation(s)
- Jeffrey C Zemla
- Department of Psychology, Syracuse University, Syracuse, NY, USA.
| | - Diane C Gooding
- Department of Psychology, College of Letters and Science, University of Wisconsin-Madison, Madison, WI, USA
- Department of Psychiatry, SMPH, University of Wisconsin-Madison, Madison, WI, USA
- Department of Medicine, Division of Gerontology and Geriatrics, SMPH, University of Wisconsin-Madison, Madison, WI, USA
| | - Joseph L Austerweil
- Department of Psychology, College of Letters and Science, University of Wisconsin-Madison, Madison, WI, USA
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Kang JW, Oremus M. Examining the Combined Effects of Social Isolation and Loneliness on Memory: A Systematic Review. Arch Gerontol Geriatr 2023; 104:104801. [PMID: 36081231 DOI: 10.1016/j.archger.2022.104801] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Some research suggests social isolation and loneliness are important risk factors for reduced successful aging and cognitive health. However, findings are inconsistent and no prior systematic review has investigated whether social isolation and loneliness are associated with the memory domain of cognition. This review examined whether social isolation and loneliness individually and jointly affected the memory of middle- and older-aged adults. METHODS We used PubMed, PsycInfo, and Scopus to search for comparative studies that examined the impact of both loneliness and social isolation (e.g., social activity, social networks) on memory (including all subtypes) in populations aged ≥ 45 years. Three raters performed data extraction and risk of bias assessment using the Joanna Briggs Institute checklist. Data were synthesized narratively following the Synthesis without Meta-Analysis guideline. RESULTS In 12 included articles, higher levels of loneliness and social isolation (combining a range of different indicators) were associated with lower memory performance, where the interaction between loneliness and social isolation had the largest adverse effect on memory, followed by social isolation alone, and followed by loneliness alone. However, substantial heterogeneity was observed in the composition of the two most common indicators of social isolation (social network size, social activity participation), with the magnitude of most results being clinically non-important. Most articles had moderate risk of bias. CONCLUSION This review found an inverse association between social isolation/loneliness and memory, and outlines future steps to systematically combine the two constructs and measure social isolation in a consistent, multi-modal format.
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Affiliation(s)
- Ji Won Kang
- School of Public Health Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada, N2L 3G1
| | - Mark Oremus
- School of Public Health Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada, N2L 3G1.
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Olmos-Villaseñor R, Sepulveda-Silva C, Julio-Ramos T, Fuentes-Lopez E, Toloza-Ramirez D, Santibañez RA, Copland DA, Mendez-Orellana C. Phonological and Semantic Fluency in Alzheimer's Disease: A Systematic Review and Meta-Analysis. J Alzheimers Dis 2023; 95:1-12. [PMID: 37482994 PMCID: PMC10578227 DOI: 10.3233/jad-221272] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2023] [Indexed: 07/25/2023]
Abstract
BACKGROUND Semantic and Phonological fluency (SF and PF) are routinely evaluated in patients with Alzheimer's disease (AD). There are disagreements in the literature regarding which fluency task is more affected while developing AD. Most studies focus on SF assessment, given its connection with the temporoparietal amnesic system. PF is less reported, it is related to working memory, which is also impaired in probable and diagnosed AD. Differentiating between performance on these tasks might be informative in early AD diagnosis, providing an accurate linguistic profile. OBJECTIVE Compare SF and PF performance in healthy volunteers, volunteers with probable AD, and patients with AD diagnosis, considering the heterogeneity of age, gender, and educational level variables. METHODS A total of 8 studies were included for meta-analysis, reaching a sample size of 1,270 individuals (568 patients diagnosed with AD, 340 with probable AD diagnosis, and 362 healthy volunteers). RESULTS The three groups consistently performed better on SF than PF. When progressing to a diagnosis of AD, we observed a significant difference in SF and PF performance across our 3 groups of interest (p = 0.04). The age variable explained a proportion of this difference in task performance across the groups, and as age increases, both tasks equally worsen. CONCLUSION The performance of SF and PF might play a differential role in early AD diagnosis. These tasks rely on partially different neural bases of language processing. They are thus worth exploring independently in diagnosing normal aging and its transition to pathological stages, including probable and diagnosed AD.
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Affiliation(s)
- Rocio Olmos-Villaseñor
- Speech and Language Therapy School, Health Sciences Department, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
- Laboratory of Language Rehabilitation and Stimulation (LARES), Speech and Language Therapy School, Health Sciences Department, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Consuelo Sepulveda-Silva
- Speech and Language Therapy School, Health Sciences Department, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
- Laboratory of Language Rehabilitation and Stimulation (LARES), Speech and Language Therapy School, Health Sciences Department, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Teresa Julio-Ramos
- Laboratory of Language Rehabilitation and Stimulation (LARES), Speech and Language Therapy School, Health Sciences Department, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Eduardo Fuentes-Lopez
- Speech and Language Therapy School, Health Sciences Department, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - David Toloza-Ramirez
- Exercise and Rehabilitation Sciences Institute, School of Speech Therapy, Faculty of Rehabilitation Sciences, Universidad Andres Bello, Santiago, Chile
| | - Rodrigo A. Santibañez
- Neurology Department, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Neurology Service, Complejo Asistencial Doctor Sótero del Río, Santiago, Chile
| | - David A. Copland
- Queensland Aphasia Research Centre, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia
| | - Carolina Mendez-Orellana
- Speech and Language Therapy School, Health Sciences Department, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
- Laboratory of Language Rehabilitation and Stimulation (LARES), Speech and Language Therapy School, Health Sciences Department, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
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