Familiarity Deficits Research Articles

Promoting a sustainable diet through carbon labeling of food: Insights from young consumers in the Americas

The agri-food system is a major contributor to global greenhouse gas emissions, and its contribution is projected to grow significantly in coming years. Consumers can drive system change and help mitigate the climate crisis through demand behaviour, with youth uniquely positioned as key actors. Carbon labelling offers a tool for informing consumers about the carbon footprint of food, and thereby promoting purchase of lower-carbon products. This cross-cultural study (n = 815) sought to investigate perceptions of carbon labels on food amongst youth (18–24 years) from two medium-high CO2-emitting countries in the Americas – Canada and Argentina. Using a mixed methods online survey approach that integrates a quantitative questionnaire with open response questions, we found knowledge deficits in familiarity with the concepts ‘carbon footprint’ and especially ‘carbon label’, and these varied with country, gender, and level of education. Further, exemplars of six food carbon labels, standardized for the carbon emissions information displayed, differed for scores of usefulness, clarity, understanding, confusion, and incomprehensibility. Labels also differed in their relative preference ratings, which varied with education level, with the ‘Traffic light horizontal scale’ the most preferred overall. Our findings inform carbon label design and emissions-related education initiatives, each of which should be optimized for different segments of the youth market in order to effectively promote consumption of lower-carbon foods.

Familiarity Deficits for Words and Objects in Amnestic Mild Cognitive Impairment in a Context Minimizing the Role of Recollection.

Amnestic mild cognitive impairment (aMCI) is associated with cortical thinning in perirhinal and entorhinal cortices, key regions of the brain supporting familiarity. Individuals with aMCI demonstrate familiarity deficits in their behavior, often repeating questions in the same conversation. While familiarity deficits in healthy aging are minimal, past studies measuring familiarity in aMCI have mixed results, perhaps due to the influence of recollection. We therefore used a paradigm that minimized the influence of recollection, and hypothesized that familiarity would be impaired in aMCI relative to age-matched controls, but not in healthy older adults relative to younger adults. We also hypothesized that familiarity deficits in aMCI would be greater for objects than words because the perirhinal cortex plays a significant role in visual discrimination. A sample of 36 younger adults, 38 cognitively intact older adults, and 30 older adults with aMCI made absolute frequency judgments for words and objects seen a variable number of times in an incidental encoding task. Estimates of familiarity were derived from correlating participants' frequency judgments with the actual frequency of presentation. Familiarity was largely spared in healthy aging, with minor deficits in familiarity for words. Familiarity deficits were evident in aMCI comparably for words and objects. The present research underscores the need to study familiarity in contexts minimizing recollection, particularly when comparing groups with different levels of recollection, and adds to our understanding of the phenomenology of aMCI. Familiarity deficits may provide an early biomarker of dementia risk.

Familiarity in Mild Cognitive Impairment as a Function of Patients' Clinical Outcome 4 Years Later.

The current study addresses the nature of memory difficulties in amnestic mild cognitive impairment (aMCI). Whereas recollection is consistently found to be impaired in aMCI, the results on familiarity are divergent. One potential factor that could explain this divergence in findings relates to the heterogeneity of aMCI patients, so that only those aMCI patients who develop Alzheimer disease (AD) may present with impaired familiarity. The present study aimed at testing this hypothesis. A group of 45 aMCI patients and a group of 26 healthy older adults performed a verbal recognition memory test with the Remember/Know paradigm to assess recollection and familiarity processes. All participants were followed for 4 years with clinical and neuropsychological testing. At the end of follow-up, 22 aMCI patients progressed to AD and 23 aMCI patients remained stable. Initial memory performance was compared between the 3 groups. Whereas recollection was severely diminished in all aMCI patients, familiarity accuracy (and consequently global recognition accuracy) was found to be impaired only in aMCI patients who subsequently developed AD. These findings suggest that the enrichment of the aMCI population with predementia stage patients may modulate the likelihood to observe familiarity deficits, and impaired global recognition accuracy may accompany incipient AD.

Deficits in recent but not lifetime familiarity in amnestic mild cognitive impairment

People with amnestic mild cognitive impairment (aMCI) repeat questions, seemingly without any sense of familiarity (i.e., recognition of prior occurrence without recollection of episodic context). Accumulation of neurofibrillary tau in preclinical Alzheimer's disease begins in perirhinal cortex, a medial temporal lobe region linked to familiarity. Both observations would predict impaired familiarity assessment in aMCI; however, the extant evidence is mixed. To reveal familiarity impairments, it may be necessary to minimize the influence of recollection. In the current study, older adults with aMCI and healthy controls were administered two tasks on which a well-characterized patient (NB) with selective familiarity impairments due to surgical left temporal lobe excision sparing the hippocampus showed abnormal performance: frequency judgments for words exposed to in a recent study phase and judgments of cumulative lifetime familiarity for object concepts denoted by words. We also administered a process dissociation procedure (PDP) task that previously revealed spared familiarity in aMCI. We predicted that familiarity would be spared in aMCI on the PDP task, but impaired when assessed by frequency judgments for recent laboratory exposures and lifetime familiarity judgments. Familiarity was spared on the PDP task, but was impaired when probed with frequency judgments for recently exposed words in aMCI. Lifetime familiarity was also not impaired in aMCI. These results highlight the benefits of studying familiarity under conditions that minimize recollection and the value of frequency judgments in revealing familiarity deficits, and suggest that perirhinal cortex may not be necessary for accessing familiarity accumulated over a lifetime of experience.

Increasing Dopamine and Acetylcholine Levels during Encoding Does Not Modulate Remember or Know Responses during Memory Retrieval in Healthy Aging—a Randomized Controlled Feasibility Study

The retrieval of information from long-term memory can be associated with information regarding sources or context (recollection) or without further context (familiarity). The retrieval type depends on how information has been encoded previously, and this encoding process is supposed to be modulated by the neurotransmitters dopamine and acetylcholine. For example, acetylcholine levels in the hippocampus increase when one is confronted with novel information allowing for better encoding and, presumably, for retrieval of more detailed memories (recollection). On the other hand, a dopaminergic deficit such as in Parkinson’s disease has been shown to induce deficits in familiarity rather than in recollection-based retrieval. It is, however, unclear whether this finding arises from alterations in encoding, retrieval, or both. Moreover, other research has challenged this clear-cut dichotomy and linked dopamine to both familiarity and recollection, and acetylcholine to unspecific enhancement of memory for novel information. Thirty-nine healthy seniors (age range 62–77) participated in a remember/know task in which scenes that were presented with different repetition rates had to be encoded and retrieved on the following day. Neurotransmitter levels were modulated during encoding by administrating either levodopa (100 mg, N = 13) or galantamine (8 mg, N = 13) to one of two experimental groups. A third group received a placebo (N = 13). Across all groups, recognition memory increased as a function of stimulus repetition, and this effect was specifically pronounced for remember relative to know answers. Importantly, the drugs had no effect on recollection, familiarity, or overall recognition memory. The findings argue against a simple dichotomy of dopaminergic and cholinergic contributions to either recollection- or familiarity-based memory retrieval.

Assessment of family physicians' awareness and knowledge of familial hypercholesterolemia in governmental hospitals in Riyadh, Saudi Arabia.

Background:Familial Hypercholesterolemia (FH) is an inherited and complex multifactorial disease that can lead to early onset of coronary artery disease (CAD). Diagnosis, treatment, and management of FH require a well-trained physician with high awareness of the disease and different risk factors to avoid complications.Materials and Methods:This cross-sectional study evaluated family physicians’ awareness and knowledge of FH using self-administered questionnaires in governmental hospitals in Riyadh, Saudi Arabia, during 2018.Results:A total of 225 family physicians completed the questionnaire, with a response rate of 58.4%. The mean age of respondents was 31.3 years and more than 59.1% were men. Although 72.4% of physicians rated their familiarity with FH as average and above, 48.4% of all participants had poor FH knowledge, while only 51.6% had acceptable FH knowledge. About 65.8% of physicians reported that they routinely take a detailed family history, perform a physical examination, and screen close relatives. Awareness of various clinical algorithms for diagnosis of patients with FH was very low at 52.0%. The mean FH knowledge and familiarity scores were significantly higher (P < 0.001) among participants who were older, had higher training levels, or longer years in practice.Conclusions:The current study revealed significant deficits in FH familiarity, awareness, knowledge, and practice among Saudi physicians. FH educational programs directed at all physicians involved in FH patients’ management are necessary to improve physicians’ knowledge of all aspects of FH management, including the importance of a mechanism for identifying people at risk for a genetic condition by a process of systematic family tracing.

S203. Impact of Schizophrenia on Temporal Context Versus Item Memory

Bridging temporal gaps are a core feature of episodic memory, allowing for “mental time travel” and a sense of recollection. Given evidence of disproportionate recollection versus familiarity deficits, we hypothesized that patients would have differential memory impairments for temporal versus item information.

Familiarity deficit, knowledge and related bioethical attributes of Nigerian university final year public health students after cancellation of free-standing bioethics course

Background: Free-standing ethics course offered to Public Health students at Madonna University Elele Campus, Rivers State, Nigeria, was cancelled. The medical ethics course is considered inadequate for public health practice. Further, theoretical ethics knowledge was criticized as not being translated to expected high standard of ethical conduct. Ethics training was thus left to mentoring, insertions and case discussions across subjects.Objective: To assess the extent of familiarity deficit with ethics related items and the level of knowledge in healthcare ethics of the affected final year students.Methodology: Self administered structured questionnaire using modified past ethics questions was the instrument for data collection. Analysis was by use of electronic calculator with results presented in percentages and bar chart.Result: Of a total of 1320 respondents the overall familiarity deficit was 380 (29%). The highest was in Evolution of Healthcare Ethics 205 (62%). Judgment of Actions in Healthcare had the least 12 (3.6%). The overall level of ethics knowledge was 284 (21.5%). The highest was in Judgment of Actions in Healthcare 126 (38%). The least was in Evolution of Healthcare Ethics 36 (11%).Conclusion: Absence of free-standing course is associated with deficiency in ethics language, history, concepts and knowledge. Free–standing course, ethical insertions across domains, awareness of mutuality of benefits in good behaviour plus character training might improve informed ethical conduct.Keywords: Hobbes, Butler, Harm, Mutuality, Benefits, Morality

Familiarity deficits in cognitively normal aging individuals with APOE ε4: A follow-up investigation of medial temporal lobe structural correlates

IntroductionThe apolipoprotein E ε4 (APOE ε4) allele is a well-documented risk factor for Alzheimer's disease (AD). Accordingly, aging individuals carrying one or more ε4 alleles are at considerably greater risk of developing AD over time. In an effort to characterize early cognitive manifestations of AD, we previously outlined selective deficits in familiarity-based recognition in otherwise asymptomatic carriers of the APOE ε4 allele (Schoemaker et al., 2016). In this follow-up report, we aimed to explore the neural correlates of this selective cognitive impairment. MethodsFor this purpose, within the same population and using high-resolution structural neuroimaging, we explored relationships between volumes of the hippocampus, entorhinal, and perirhinal cortices and performance in recollection and familiarity. ResultsOverall, our results revealed significant positive relationships between familiarity performance and volumes of the perirhinal and entorhinal cortices in aging individuals with APOE ε4. In APOE ε4 carriers, a positive correlation between recollection performance and hippocampal volume was also found. In contrast, no correlation reached statistical significance in the group of noncarriers. ConclusionThese findings suggest that familiarity performance might be a useful marker of the integrity of the rhinal cortex, especially in populations at risk of AD.

Hyperfamiliarity in Amnestic and Vascular Mild Cognitive Impairment.

Hyperfamiliarity is a phenomenon where new stimuli are perceived as familiar. Previous studies have demonstrated familiarity disorder in mild cognitive impairment (MCI), but mostly from the perspective of a neuropsychological approach, and the exact correlation of MCI aetiologies with the phenomenon remains uncertain. Based on current evidence suggesting a frontal-subcortical pathway contributing to familiarity processing, we hypothesize that individuals with a vascular aetiology of MCI will likely suffer more familiarity deficits. This study aims to examine the real-life hyperfamiliarity symptoms in amnestic versus vascular MCI. Informants of 11 amnestic and 9 vascular cognitive impairment patients were interviewed about the frequency of hyperfamiliarity symptoms in the previous month. MRI brain images of vascular cognitive impairment patients were analysed as well. Patients with vascular cognitive impairment with no dementia (VCIND) showed a significantly higher frequency of hyperfamiliarity for people but not places or objects. Within VCIND patients, overall basal ganglia hyperintensities, particularly in the putamen, were found to significantly correlate to hyperfamiliarity. Patients with VCIND suffer more real-life hyperfamiliarity during people recognition compared to patients with amnestic mild cognitive impairment (aMCI), despite a comparative global decline in cognitive. This is likely due to impaired memory retrieval and matching processes resulting from subcortical ischaemic lesions.

Selective familiarity deficits in otherwise cognitively intact aging individuals with genetic risk for Alzheimer's disease

IntroductionFamiliarity has been associated with integrity of the rhinal cortex. Thus, impairment in familiarity is expected in very early stages of Alzheimer's disease (AD). The apolipoprotein E (APOE) ε4 allele is a major risk factor for AD. Here, we investigated the effect of the APOE ε4 status on familiarity in cognitively normal aging individuals. MethodsEighty-one individuals aged between 55 and 80 years, 21 carriers and 60 noncarriers, were used in these analyses. A cognitive evaluation was performed on all participants to document the absence of objective cognitive deficits. The effect of APOE ε4 status on familiarity was tested using independent sample t test and an analysis of covariance controlling for age, gender, and education. ResultsThe groups did not differ in term of age, education, and male/female ratio. APOE ε4 carriers showed a significant reduction in familiarity. No other cognitive deficit was observed in the group of ε4 carriers, relative to noncarriers. DiscussionAPOE ε4 is associated with a reduction in familiarity in the absence of other cognitive deficits. These results suggest that performance in familiarity could represent an early cognitive marker for individuals at risk of AD.

The Interaction Between Memory Trace and Memory Judgment in Age-Related Decline

Background/Study Context: Associative memory deficit and executive functioning deficit are two alternative—but nonexclusive—accounts of the episodic memory deficit observed in aging. The first explain the episodic memory decline generally observed in aging by an associative memory deficit (memory decline per se), whereas the second explains it by an executive functioning deficit. This distinction could be critical in early discrimination between healthy aging and very mild Alzheimer’s-type dementia.Methods: Memory performance was measured in older adults (n = 20) and paired younger participants (n = 20), whereas the facial expression and auditory context (spoken voice) associated with the face were manipulated between study and test. Recollection and familiarity were estimated using a remember/know judgment, and source memory performance was obtained depending on the information to retrieve.Results: Although no between-group difference was observed for correctly recognized old faces, older participants made more false alarms than younger ones, thus revealing lower discriminability (d’). Facial expression change decreased recognition for all participants, whereas auditory context change decreased recognition only for younger participants. Remember/know judgments revealed age-related deficits in both recollection and familiarity, the relative decrease in familiarity reported by older adults was particularly large in the expression change conditions, and a disadvantage in source memory performance was particularly pronounced when the task was to retrieve auditory context associated with the face at study.Conclusions: The present findings show that age-related associative memory differences occur with familiarity as well as recollection and are observed in situations that do not necessarily require conscious retrieval. This age-related decline is more prominent for multimodal (face–auditory context) than for intraitem (face-expression) associations. The value of exploring both memory trace and memory judgment was discussed, and potential applications for the development of neuropsychological tools for memory assessment in aging were highlighted.

The effects of healthy aging, amnestic mild cognitive impairment, and Alzheimer's disease on recollection and familiarity: a meta-analytic review.

It is well established that healthy aging, amnestic Mild Cognitive Impairment (aMCI), and Alzheimer's Disease (AD) are associated with substantial declines in episodic memory. However, there is still debate as to how two forms of episodic memory - recollection and familiarity - are affected by healthy and pathological aging. To address this issue we conducted a meta-analytic review of the effect sizes reported in studies using remember/know (RK), receiver operating characteristic (ROC) and process dissociation (PD) methods to examine recollection and familiarity in healthy aging (25 published reports), aMCI (9 published reports), and AD (5 published reports). The results from the meta-analysis revealed that healthy aging is associated with moderate-to-large recollection impairments. Familiarity was not impaired in studies using ROC or PD methods but was impaired in studies that used the RK procedure. aMCI was associated with large decreases in recollection whereas familiarity only tended to show a decrease in studies with a patient sample comprised of both single-domain and multiple-domain aMCI patients. Lastly, AD was associated with large decreases in both recollection and familiarity. The results are consistent with neuroimaging evidence suggesting that the hippocampus is critical for recollection whereas familiarity is dependent on the integrity of the surrounding perirhinal cortex. Moreover, the results highlight the relevance of method selection when examining aging, and suggest that familiarity deficits might be a useful behavioral marker for identifying individuals that will develop dementia.

Exploring recollection and familiarity impairments in Parkinson’s disease

There is conflicting evidence on whether patients diagnosed with Parkinson’s disease (PD) have cognitive deficits associated with episodic memory and particularly with recognition memory. The aim of the present study was to explore whether PD patients exhibit deficits in recollection and familiarity, the two processes involved in recognition. A sample of young healthy participants (22) was tested to verify that the experimental tasks were useful estimators of recognition processes. Two further samples—one of elderly controls (16) and one of PD patients (20)—were the main focus of this research. All participants were exposed to an associative recognition test aimed at estimating recollection followed by a two-alternative forced-choice (2AFC) test designed to estimate familiarity. The analyses showed a deficit in associative recognition in PD patients and no difference between elderly controls and PD patients in the 2AFC test. By contrast, young healthy participants were better than elderly controls and PD patients in both components of recognition. Further analyses of results of the 2AFC test indicated that the measure chosen to estimate conceptual familiarity was adequate.

Type 2 diabetes and impaired glucose tolerance are associated with word memory source monitoring recollection deficits but not simple recognition familiarity deficits following water, low glycaemic load, and high glycaemic load breakfasts

BackgroundIt has been established that type 2 diabetes, and to some extent, impaired glucose tolerance (IGT), are associated with general neuropsychological impairments in episodic memory. However, the effect of abnormalities in glucose metabolism on specific retrieval processes such as source monitoring has not been investigated. The primary aim was to investigate the impact of type 2 diabetes and IGT on simple word recognition (familiarity) and complex source monitoring (recollection). A secondary aim was to examine the effect of acute breakfast glycaemic load manipulations on episodic memory. MethodData are presented from two separate studies; (i) 24 adults with type 2 diabetes and 12 controls aged 45–75years, (ii) 18 females with IGT and 47 female controls aged 30–50years. Controls were matched for age, IQ, BMI, waist circumference, and depression. Recognition of previously learned words and memory for specifically which list a previously learned word had appeared in (source monitoring) was examined at two test sessions during the morning after consumption of low glycaemic load, high glycaemic load and water breakfasts according to a counterbalanced, crossover design. ResultsType 2 diabetes (p<0.05) and IGT (p<0.01) were associated with significant source monitoring recollection deficits but not impairments in familiarity. Impairments were only observed in the late postprandial stage at the second test session. These impairments were not attenuated by the breakfast glycaemic load manipulations. ConclusionsIsolated source monitoring recollection deficits indicate that abnormalities in glucose metabolism are not detrimental for global episodic memory processes. This enhances our understanding of how metabolic disorders are associated with memory impairments.

Famous face identification in temporal lobe epilepsy: Support for a multimodal integration model of semantic memory

This study aims to demonstrate that the left and right anterior temporal lobes (ATLs) perform critical but unique roles in famous face identification, with damage to either leading to differing deficit patterns reflecting decreased access to lexical or semantic concepts but not their degradation. Famous face identification was studied in 22 presurgical and 14 postsurgical temporal lobe epilepsy (TLE) patients and 20 healthy comparison subjects using free recall and multiple choice (MC) paradigms. Right TLE patients exhibited presurgical deficits in famous face recognition, and postsurgical deficits in both famous face recognition and familiarity judgments. However, they did not exhibit any problems with naming before or after surgery. In contrast, left TLE patients demonstrated both pre- and postsurgical deficits in famous face naming but no significant deficits in recognition or familiarity. Double dissociations in performance between groups were alleviated by altering task demands. Postsurgical right TLE patients provided with MC options correctly identified greater than 70% of famous faces they initially rated as unfamiliar. Left TLE patients accurately chose the name for nearly all famous faces they recognized (based on their verbal description) but initially failed to name, although they tended to rapidly lose access to this name. We believe alterations in task demands activate alternative routes to semantic and lexical networks, demonstrating that unique pathways to such stored information exist, and suggesting a different role for each ATL in identifying visually presented famous faces. The right ATL appears to play a fundamental role in accessing semantic information from a visual route, with the left ATL serving to link semantic information to the language system to produce a specific name. These findings challenge several assumptions underlying amodal models of semantic memory, and provide support for the integrated multimodal theories of semantic memory and a distributed representation of concepts.

Neural correlates of relational and item-specific encoding during working and long-term memory in schizophrenia

Successful long-term memory (LTM) depends upon effective control of information in working memory (WM), and there is evidence that both WM and LTM are impaired by schizophrenia. This study tests the hypothesis that LTM deficits in schizophrenia may result from impaired control of relational processing in WM due to dorsolateral prefrontal cortex (DLPFC) dysfunction. fMRI was performed on 19 healthy controls and 20 patients with schizophrenia during WM tasks emphasizing relational (reorder trials) versus item-specific (rehearse trials) processing. WM activity was also examined with respect to LTM recognition on a task administered outside the scanner. Receiver operator characteristic analysis assessed familiarity and recollection components of LTM. Patients showed a disproportionate familiarity deficit for reorder versus rehearse trials against a background of generalized LTM impairments. Relational processing during WM led to DLPFC activation in both groups. However, this activation was less focal in patients than in controls, and patients with more severe negative symptoms showed less of a DLPFC increase. fMRI analysis of subsequent recognition performance revealed a group by condition interaction. High LTM for reorder versus rehearse trials was associated with bilateral DLPFC activation in controls, but not in patients who activated the left middle temporal and inferior occipital gyrus. Results indicate that although patients can activate the DLPFC on a structured relational WM task, this activation is less focal and does not translate to high retrieval success, suggesting a disruption in the interaction between WM and LTM processes in schizophrenia.

Impact of novelty and type of material on recognition in healthy older adults and persons with mild cognitive impairment

The goal of this study was to assess the effect of novelty on correct recognition (hit minus false alarms) and on recollection and familiarity processes in normal aging and amnestic mild cognitive impairment (MCI). Recognition tasks compared well-known and novel stimuli in the verbal domain (words vs. pseudowords) and in the musical domain (well-known vs. novel melodies). Results indicated that novel materials associated with lower correct recognition and lower recollection, an effect that can be related to its lower amenability to elaborative encoding in comparison with well-known items. Results also indicated that normal aging impairs recognition of well-known items, whereas MCI impairs recognition of novel items only. Healthy older adults showed impaired recollection and familiarity relative to younger controls and individuals with MCI showed impaired recollection relative to healthy older adults. The recollection deficit in healthy older adults and persons with MCI and their impaired recognition of well-known items is compatible with the difficulty both groups have in encoding information in an elaborate manner. In turn, familiarity deficit could be related to impaired frontal functioning. Therefore, novelty of material has a differential impact on recognition in persons with age-related memory disorders.

Selective familiarity deficits after left anterior temporal-lobe removal with hippocampal sparing are material specific

Research has firmly established a link between recognition memory and the functional integrity of the medial temporal lobes (MTL). Dual-process models of MTL organization maintain that there is a division of labour within the MTL, with the hippocampus (HC) supporting recollective processes and perirhinal cortex (PRc) supporting familiarity assessment. An older neuropsychological literature suggested a different type of division of labour within the MTL, with left-sided structures playing a critical role in memory for verbal materials and right-sided structures being differentially involved in memory for material that cannot easily be verbalized. Research that has related predictions made by these two accounts to each other is limited. Evidence from research in patients with selective recollection impairments and fMRI data in healthy individuals suggests that lateralization of recollection for verbal materials is not clear-cut. Here we examined lateralization of familiarity processes in the MTL by asking whether selective familiarity impairments after unilateral anterior temporal-lobe removal with hippocampal sparing are material specific. We examined this issue in NB, an individual who was previously shown to exhibit selective familiarity impairments with such a lesion (Bowles et al., 2007). We administered three similar recognition memory tests in combination with the same Remember–Know procedure for three different types of novel stimuli without pre-existing semantic representations. Analyses focused on discrimination and on possible differences in response criterion, and included an ROC based approach as well. We found that NB exhibited a deficit in overall recognition of aurally presented pronounceable non-words that reflected a specific impairment of familiarity assessment with preservation of recollective processes. Examination of recognition memory for visually presented abstract pictures and faces did not reveal any impairment, neither at the level of overall recognition nor, more specifically, at the level of familiarity assessment. These findings suggest that the neural mechanisms that support familiarity assessment in the temporal lobe operate in a manner that is tied to the specific stimulus class being assessed.

Double dissociation between familiarity and recollection in Parkinson's disease as a function of encoding tasks

Parkinson's disease (PD) is associated with episodic memory deficits, but their exact nature is unclear. Some dual-process studies have suggested that recollection is impaired and familiarity is spared in PD, yet others have found the opposite. Our goal was to investigate these memory processes in PD and determine whether the inconsistency among existing findings is related to differences in encoding conditions. We used a process-dissociation procedure with word pairs to estimate familiarity and recollection. In Experiment 1, we used a directed, deep, relational encoding condition (i.e., sentence generation), and in Experiment 2, we contrasted this encoding condition with a shallower, non-directed encoding condition (i.e., read condition). We found a double dissociation as a function of the encoding task: In the sentence generation encoding condition, recollection was impaired in the PD patients, but familiarity was spared. In contrast, in the read encoding condition, there was no group difference in recollection, but familiarity was impaired in the PD group. Within-subject comparisons revealed that both control and PD participants benefitted from the provision of a directed, deep relational encoding strategy. However, this benefit was manifested as an increase in recollection in the controls, but an increase in familiarity in the PD patients. These findings help to reconcile the extant literature and suggest that episodic memory deficits in PD are two-fold, involving: (1) difficulties instantiating encoding strategies independently, leading to deficits in familiarity, and (2) impaired recollection when encoding strategies are equated across groups. Our results highlight the importance of controlling encoding conditions between groups and of taking account of other variables that may influence the participants’ performance, such as deficits associated with normal aging, which may mask deficits in neurodegenerative diseases in particular situations. More generally, our study raises the possibility that deficits in recollection or familiarity in patient populations are not immutably linked to the structure that is affected, as is typically assumed, but that such deficits may interact with type of encoding, and possibly with the nature of the retrieval process.