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Frontiers in Neuroscience 2023Cognitive loss in older adults is a growing issue in our society, and there is a need to develop inexpensive, simple, effective in-home treatments. This study was... (Review)
Review
OBJECTIVE
Cognitive loss in older adults is a growing issue in our society, and there is a need to develop inexpensive, simple, effective in-home treatments. This study was conducted to explore the use of olfactory enrichment at night to improve cognitive ability in healthy older adults.
METHODS
Male and female older adults ( = 43), age 60-85, were enrolled in the study and randomly assigned to an Olfactory Enriched or Control group. Individuals in the enriched group were exposed to 7 different odorants a week, one per night, for 2 h, using an odorant diffuser. Individuals in the control group had the same experience with amounts of odorant. Neuropsychological assessments and fMRI scans were administered at the beginning of the study and after 6 months.
RESULTS
A statistically significant 226% improvement was observed in the enriched group compared to the control group on the Rey Auditory Verbal Learning Test and improved functioning was observed in the left uncinate fasciculus, as assessed by mean diffusivity.
CONCLUSION
Minimal olfactory enrichment administered at night produces improvements in both cognitive and neural functioning. Thus, olfactory enrichment may provide an effective and low-effort pathway to improved brain health.
PubMed: 37554295
DOI: 10.3389/fnins.2023.1200448 -
Psychiatry Research Dec 2023Twenty years ago, cognitive impairments were recognized as an unmet treatment need in schizophrenia. Basic science discoveries in neuroplasticity had led to cognitive...
Twenty years ago, cognitive impairments were recognized as an unmet treatment need in schizophrenia. Basic science discoveries in neuroplasticity had led to cognitive training approaches for dyslexia. We wondered whether a similar approach could target working memory deficits in schizophrenia by harnessing plasticity in the auditory cortex. Our per protocol experimental therapeutics studies tested the hypothesis that sharpening auditory cortical representations would result in better verbal learning and memory. We also later studied the effects of intensive training of basic social cognitive operations. Our training protocols were deliberately focused, effortful and intensive, since participants were often up against decades of cortical dysplasticity. In studies in different stages of illness, we demonstrated that neuroscience-informed cognitive training was associated with: (1) proximal psychophysical as well as distal cognitive improvements; (2) increases in serum BDNF levels; (3) negative effects of serum anticholinergic burden; (4) electrophysiologic responses and brain activation patterns consistent with restorative neuroplastic changes in cortex; (5) positive cortical and thalamic volumetric changes suggestive of neuroprotection; (6) better 6-month clinical functioning in those with a positive initial response. Taken together, this work indicates how much the field of psychiatry could benefit from a deep understanding of the basic science of cortical neuroplasticity processes and of how they can be deliberately and efficiently harnessed for therapeutic purposes.
Topics: Humans; Schizophrenia; Memory, Short-Term; Cognitive Dysfunction; Memory Disorders; Neuronal Plasticity
PubMed: 38000206
DOI: 10.1016/j.psychres.2023.115607 -
Neuropsychology Review Mar 2024Olfactory training (OT), or smell training,consists of repeated exposure to odorants over time with the intended neuroplastic effect of improving or remediating... (Review)
Review
Olfactory training (OT), or smell training,consists of repeated exposure to odorants over time with the intended neuroplastic effect of improving or remediating olfactory functioning. Declines in olfaction parallel declines in cognition in various pathological conditions and aging. Research suggests a dynamic neural connection exists between olfaction and cognition. Thus, if OT can improve olfaction, could OT also improve cognition and support brain function? To answer this question, we conducted a systematic review of the literature to determine whether there is evidence that OT translates to improved cognition or altered brain morphology and connectivity that supports cognition. Across three databases (MEDLINE, Scopus, & Embase), 18 articles were identified in this systematic review. Overall, the reviewed studies provided emerging evidence that OT is associated with improved global cognition, and in particular, verbal fluency and verbal learning/memory. OT is also associated with increases in the volume/size of olfactory-related brain regions, including the olfactory bulb and hippocampus, and altered functional connectivity. Interestingly, these positive effects were not limited to patients with smell loss (i.e., hyposmia & anosmia) but normosmic (i.e., normal ability to smell) participants benefitted as well. Implications for practice and research are provided.
Topics: Humans; Brain; Cognition; Olfaction Disorders; Olfactory Training; Smell
PubMed: 36725781
DOI: 10.1007/s11065-022-09573-0 -
Canadian Journal of Psychiatry. Revue... May 2024Our aims were to assess cognitive impairment in bipolar patients in remission compared with healthy controls, and to study its connection to clinical and therapeutic...
OBJECTIVES
Our aims were to assess cognitive impairment in bipolar patients in remission compared with healthy controls, and to study its connection to clinical and therapeutic factors.
METHODOLOGY
This was a case-control study of patients with bipolar disorder (BD) in remission and matched healthy controls. It was carried out at the Hédi Chaker University Hospital in Sfax, Tunisia. The Screen for Cognitive Impairment in Psychiatry (SCIP) scale was used to assess cognitive function in patients and controls. This scale comprises subtests for verbal learning with immediate (VLT-I) and delayed (VLT-D) recall, working memory (WMT), verbal fluency (VFT) and information processing speed (PST).
RESULTS
We recruited 61 patients and 40 controls. Compared with controls, patients had significantly lower scores on the overall SCIP scale and on all SCIP subtests ( < 0.001 throughout) with moderate to high effects. In multivariate analysis, the presence of psychotic characteristics correlated with lower scores on the overall SCIP ( = 0.001), VLT-I ( = 0.001) and VLT-D ( = 0.007), WMT ( = 0.002) and PST ( = 0.008). Bipolar II correlated with lower LTV-I scores ( = 0.023). Age of onset and duration of the disorder were negatively correlated with PST scores ( < 10 and = 0.007, respectively). Predominantly manic polarity correlated with lower VFT scores ( = 0.007).
CONCLUSIONS
Our study showed that bipolar patients in remission presented significantly more marked cognitive impairments, affecting various cognitive domains, than the controls. These cognitive impairments appear to be linked to clinical and therapeutic factors that are themselves considered to be factors of poor prognosis in BD.
PubMed: 38783828
DOI: 10.1177/07067437241253631 -
The American Psychologist Feb 2024This article presents an obituary for Endel Tulving. Tulving's educational and professional careers are summarized. His work in the field of human memory is detailed. It...
This article presents an obituary for Endel Tulving. Tulving's educational and professional careers are summarized. His work in the field of human memory is detailed. It is noted that Tulving's look at the field of verbal learning in the late 1950s persuaded him that the dominant associative tradition missed many important aspects of human memory. His research found that at the time of retrieval, memory for the original event may be successfully reinstated only by contextual cues that interact in a complementary fashion with the specifically encoded memory trace, a process that Tulving referred to as "synergistic ecphory". He is also known for his work on memory systems. In his book, Elements of Episodic Memory published in 1983, Tulving proposed that memory for experienced events, episodic memory, should be distinguished from general knowledge of the world, semantic memory, and from procedural memory, the learned ability to perform such skilled procedures as riding a bicycle or playing a musical instrument. He also proposed an evolutionary framework for these different but related systems, suggesting that simple animals show only procedural memory, more complex animals are consciously aware of their knowledge of the world, but only humans possess episodic memory-the ability to use "mental time travel" to consciously recreate past experiences and to imagine possible future events. Although known initially for his purely cognitive behavioral research, during the 1980s and 1990s, Tulving increasingly incorporated neuropsychological and neuroimaging approaches into his work. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
PubMed: 38421770
DOI: 10.1037/amp0001328 -
Journal of Affective Disorders Oct 2023Recent studies indicate accelerated ageing processes, shorter telomere length and poorer cognitive functioning in patients with bipolar disorder. The neurobiology...
INTRODUCTION
Recent studies indicate accelerated ageing processes, shorter telomere length and poorer cognitive functioning in patients with bipolar disorder. The neurobiology underlying cognitive function in bipolar disorder is yet to be established. We anticipated that accelerated ageing as indicated by shortened telomere length, would be associated with reduced cognitive performance in bipolar disorder, particularly for ageing sensitive functions such as memory and learning.
METHODS
The study consisted of 647 participants (bipolar disorder [n = 246] and healthy controls [n = 401]). All participants underwent a standardized neuropsychological test battery, including working memory, executive functioning, processing speed, verbal learning, and verbal memory. Leucocyte telomere length was measured via blood and determined by quantitative real-time Polymerase Chain Reaction (qPCR) providing a telomere to single copy ratio (T/S ratio). The T/S ratio was used as an estimate of the mean telomere length of each participant. All analyses were adjusted for medication, Daily Defined Dose (DDD), chronological age, sex, and ethnicity.
RESULTS
Patients had shorter telomere lengths than healthy controls (Cohen's d = 0.11, p = 0.01). Within patients', a positive association was observed for verbal learning and telomere length (β = 0.14, p = 0.025), along with a trend for verbal memory and telomere length (β = 0.11, p = 0.07). No other associations were observed for telomere length and cognitive functioning in the patient or the control group (p > 0.1).
CONCLUSION
Our study may suggest poorer brain health in bipolar disorder as indexed by shorter telomere length and reduced learning correlates. However, the role of telomere length on cognitive functioning in bipolar disorder seems limited.
Topics: Humans; Bipolar Disorder; Telomere Shortening; Telomere; Neuropsychological Tests; Memory, Short-Term; Verbal Learning
PubMed: 37459977
DOI: 10.1016/j.jad.2023.07.087 -
Schizophrenia Research. Cognition Sep 2023In the general population, repeated cognitive testing produces learning effects with potential for improved test performance. It is currently unclear whether the same...
OBJECTIVE
In the general population, repeated cognitive testing produces learning effects with potential for improved test performance. It is currently unclear whether the same effect of repeated cognitive testing on cognition pertains to people living with schizophrenia, a condition often associated with significant cognitive impairments. This study aims to evaluate learning ability in people with schizophrenia and-considering the evidence that antipsychotic medication can additionally impair cognitive performance-explore the potential impact of anticholinergic burden on verbal and visual learning.
METHOD
The study included 86 patients with schizophrenia, treated with clozapine, who had persisting negative symptoms. They were assessed at baseline, weeks 8, 24 and 52 using Positive and Negative Syndrome Scale, Hopkins Verbal Learning Test-Revised (HVLT-R) and Brief Visuospatial Memory Test-R (BVMT-R).
RESULTS
There were no significant improvements in verbal or visual learning across all measurements. Neither the clozapine/norclozapine ratio nor anticholinergic cognitive burden significantly predicted participants' total learning. Premorbid IQ was significantly associated with verbal learning on the HVLT-R.
CONCLUSIONS
These findings advance our understanding of cognitive performance in people with schizophrenia and demonstrate limited learning performance in individuals with treatment-refractory schizophrenia.
PubMed: 37006704
DOI: 10.1016/j.scog.2023.100283 -
International Journal of Molecular... Nov 2023Autism spectrum disorder (ASD) is a neurodevelopmental disability and recent evidence suggests that autistic adults are more likely to develop Alzheimer's disease (Alz)...
Autism spectrum disorder (ASD) is a neurodevelopmental disability and recent evidence suggests that autistic adults are more likely to develop Alzheimer's disease (Alz) and other dementias compared to neurotypical (NT) adults. The ε4-allele of the Apolipoprotein E () gene is the strongest genetic risk factor for Alz and negatively impacts cognition in middle-aged and older (MA+) adults. This study aimed to determine the impact of the ε4-allele on verbal learning and memory in MA+ autistic adults (ages 40-71 years) compared to matched NT adults. Using the Auditory Verbal Learning Test (AVLT), we found that ε4 carriers performed worse on short-term memory and verbal learning across diagnosis groups, but there was no interaction with diagnosis. In exploratory analyses within sex and diagnosis groups, only autistic men carrying ε4 showed worse verbal learning ( = 0.02), compared to autistic men who were not carriers. Finally, the ε4-allele did not significantly affect long-term memory in this sample. These findings replicate previous work indicating that the ε4-allele negatively impacts short-term memory and verbal learning in MA+ adults and presents new preliminary findings that MA+ autistic men may be vulnerable to the effects of ε4 on verbal learning. Future work with a larger sample is needed to determine if autistic women may also be vulnerable.
Topics: Adult; Aged; Female; Humans; Male; Middle Aged; Alleles; Alzheimer Disease; Apolipoprotein E4; Apolipoproteins E; Autism Spectrum Disorder; Autistic Disorder; Genotype; Neuropsychological Tests; Verbal Learning
PubMed: 37958971
DOI: 10.3390/ijms242115988