Mild cognitive impairment: deficits in cognitive domains other than memory

Patients with mild cognitive impairment (MCI) typically present with memory complaints, but may have mild deficits in other cognitive domains. We compared the neuropsychological profiles of a series of consecutive MCI patients (n = 116) with a control group of healthy elderly subjects (n = 63). The presence of a memory deficit on delayed recall was consistent in the MCI sample, as it was an inclusion criterion in the study. Impairment on immediate recall was present in 62.6% of the patients on paragraph recall of the logical memory test and in 63.1% of the patients on the word paired-associate learning test. Remarkably, patients with MCI frequently had deficits in cognitive domains beyond memory. As much as 68.7% of the patients had deficits in temporal orientation, 30.2% had deficits in semantic fluency, 33.7% in the Token test, 23.4% in calculation, and 23.9% in motor initiative. If detailed neuropsychological testing is performed, the majority of MCI patients will have deficits in cognitive domains other than memory.     

Vascular risk factors and intensity of cognitive dysfunction in MCI

Patients with Mild Cognitive Impairment (MCI) have a greater risk of developing dementia than general population. Lots of evidence suggests that cardiovascular risk factors appear more often in the MCI than in general population The aim of this study was to evaluate association between cardiovascular risk factors and intensity of cognitive impairment in MCI patients. We evaluated 24 MCI patients (9 women and 15 men) fulfilling Mayo Clinic Group Criteria. Taking under consideration presence of cardiovascular diseases patients were divided into two groups: first group (n=16) MCI with cardiovascular diseases and second group (n=8) MCI without cardiovascular disorders. Cognitive functions were assessed by neuropsychological tests battery including MMSE, Clock Drawing Test, Trail Making Test (TMT), Verbal Fluency Test with letters FAS, Auditory Verbal Learning Test (AVLT). In the MCI group with vascular risk factors we have found more distinct dysfunction of learning new information, recall and short-term memory than in MCI patients without vascular pathology. In conclusion we may suggest that more distinct cognitive deficit may indicate higher risk of developing dementia, that is why patients with MCI should be under special supervision, with at least annual neuropsychological evaluation.     

Automated Neuropsychological Test Battery (CANTAB) in mild cognitive impairment and in Alzheimer's disease

Neuropsychological deficits, such as poor episodic memory, are consistent features of mild cognitive impairment and also that of early stage of dementia. The aim of the present study was to detect cognitive dysfunction among patients with Alzheimer's disease or with mild cognitive impairment (MCI), which refers to a transitional state between the cognition of normal aeging and mild dementia regarded as a high-risk condition for the development of clinically probable Alzheimer's disease (AD). Computerized tests of memory, attention and executive functions were studied in groups of AD subjects (n=15) and MCI subjects (n=25). On all measures, the performance of the AD group was significantly weaker compared to healthy individuals or to the MCI group. The performance of both the AD and MCI patients in the Paired Associate Learning test was significantly impaired, which may suggest that MCI patients are already in the early stages of the disease.     

Memory evaluation in mild cognitive impairment using recall and recognition tests

Amnestic mild cognitive impairment (MCI) is a selective episodic memory deficit that often indicates early Alzheimer's disease. Episodic memory function in MCI is typically defined by deficits in free recall, but can also be tested using recognition procedures. To assess both recall and recognition in MCI, MCI (n = 21) and older comparison (n = 30) groups completed the USC-Repeatable Episodic Memory Test. Subjects memorized two verbally presented 15-item lists. One list was used for three free recall trials, immediately followed by yes/no recognition. The second list was used for three-alternative forced-choice recognition. Relative to the comparison group, MCI had significantly fewer hits and more false alarms in yes/no recognition, and were less accurate in forced-choice recognition. Signal detection analysis showed that group differences were not due to response bias. Discriminant function analysis showed that yes/no recognition was a better predictor of group membership than free recall or forced-choice measures. MCI subjects recalled fewer items than comparison subjects, with no group differences in repetitions, intrusions, serial position effects, or measures of recall strategy (subjective organization, recall consistency). Performance deficits on free recall and recognition in MCI suggest a combination of both tests may be useful for defining episodic memory impairment associated with MCI and early Alzheimer's disease.     

Semantic knowledge in mild cognitive impairment and mild Alzheimer's disease

The aim of this study was to investigate memory in patients with mild cognitive impairment (MCI) and mild Alzheimer's disease (AD). Ten patients with MCI, 11 with AD and a group of age and education matched healthy control participants were assessed on a comprehensive battery of semantic memory tests, including traditional semantic memory measures and a non-verbal test of knowledge of object use. The MCI group was impaired on tests of category fluency and all three conditions of an object knowledge test (matching to recipient, function and action), plus a difficult object-naming test. The mild AD group showed additional impairments on traditional measures of semantic memory, including naming high frequency items, comprehension and semantic association. Together these findings suggest that semantic memory impairments occur early in the course of AD, more specifically in patients with "amnesic" MCI, and provide further evidence that impaired category fluency reflects semantic breakdown.     

Greater memory impairment in dementing females than males relative to sex-matched healthy controls

Previously we demonstrated sex differences in episodic memory in healthy elderly and suggested that normative data be separated by sex. The present study extended the exploration of sex differences on memory measures into two clinical populations, mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Seventy-six subjects with MCI and 101 subjects with AD diagnosed by a multidisciplinary team were included. These two groups were also compared to a group of 177 healthy elderly control participants. Sex differences on the Rey Auditory Verbal Learning Test (RAVLT; total and delayed recall) raw scores and Brief Visuospatial Memory Test–Revised (BVMT–R) were demonstrated within the healthy but not the MCI or AD groups. Calculating z scores by sex for both dementing groups based on the healthy controls suggested a larger performance gap between healthy and dementing women than between healthy and dementing men. MCI females were on average 0.48 standard deviations lower for total verbal learning compared to healthy female controls than were MCI males when compared to healthy male controls. For verbal delayed recall the gap was even larger (SD = 1.09). Similarly, on the BVMT–R, a measure of visual memory, the difference was 0.60 standard deviations for total visual learning and 0.99 standard deviations for delayed recall. This same sex difference, with females showing greater impairment compared to the controls group than did the males, was also present within the AD group. The greater memory impairment in dementing females rather than males when compared to sex-matched healthy controls was unlikely to be due to more severe illness since females performed equivalently to males on the Clinical Dementia Rating Scale, Mini-Mental Status Examination, and Dementia Rating Scale, and were also similar for age, education, and apolipoprotein status. The present study suggested relatively greater memory impairment in females with MCI or AD than in controls.     

Verbal Learning Differences in Epileptic Patients with Left and Right Temporal Lobe Foci

A verbal learning test patterned after and using the same format as the Rey Auditory-Verbal Learning Test was administered to the following three groups: (1) patients with left temporal lobe epilepsy (L-TLE) as defined by EEG criteria (n = 11); (2) patients with right temporal lobe epilepsy (n = 10); and (3) normal controls (n = 11). Performance was highly similar for all three groups during the five immediate recall learning trials. The performance of the L-TLE group, averaged across three delayed recall trials (free recall, phonemic cued recall, semantic cued recall), was significantly poorer than that of the other two groups. The L-TLE group showed the worst performance on the phonemic cued recall trial, poor performance on the delayed free recall trial, and relatively intact performance on the semantic cued recall trial. Immediate and delayed free recall and phonemic and semantic cued recall for the distractor list did not discriminate groups. Word frequency, word presentation order, and concrete versus abstract words did not have different effects across groups.     

Effects of level of processing at encoding and types of retrieval task in mild cognitive impairment and normal aging

A total of 16 young (M = 27.25 years), 13 healthy elderly (M = 75.38 years), and 10 older adults with probable mild cognitive impairment (MCI; M = 78.6 years) carried out a task under two different encoding conditions (shallow vs. semantic) and two retrieval conditions (free recall vs. recognition). For the shallow condition, participants had to decide whether the first or last letter of each word in a list was "E." For the semantic condition, they had to decide whether each word represented a concrete or abstract entity. The MCI group was only able to benefit from semantic encoding to the same extent as the healthy older adults in the recognition task, whereas the younger and healthy older adults benefited in both retrieval tasks. These results suggest that the MCI group required cognitive support at retrieval to make effective use of semantic processing carried out at encoding. In the discussion, we suggest that adults with MCI engage more in deep processing, using the semantic network, than hitherto thought.     

Effects of galantamine on working memory and global functioning in patients with mild cognitive impairment: a double-blind placebo-controlled study

Mild cognitive impairment (MCI) causes memory impairment and executive function deficits in those with the condition. There is also some evidence that MCI patients are impaired in their daily functioning. Cholinesterase inhibitors have been widely used for patients with Alzheimer's disease (AD), with evidence of improving cognitive function. There is currently no established treatment for MCI, and cholinesterase inhibitors are beginning to be studied in these patients. Galantamine is a cholinesterase inhibitor that also has nicotinic receptor-modulating properties that has been successful in improving AD patients. This study examined the effects of galantamine in patients with MCI in areas of memory, executive functioning, and global functioning. There was a significant improvement in scores on the Functional Activities Questionnaire, which is a measure of global functioning. There were also improvements in the galantamine group on two of six measures in the Cambridge Automated Neuropsychiatric Test Assessment Battery and in immediate free recall on the California Verbal Learning Test.     

Schizophrenia patients demonstrate a dissociation on declarative and non-declarative memory tests

Declarative memory refers to the recall and recognition of factual information. In contrast, non-declarative memory entails a facilitation of memory based on prior exposure and is typically assessed with priming and perceptual-motor sequencing tasks. In this study, schizophrenia patients were compared to normal comparison subjects on two computerized memory tasks: the Word-stem Priming Test (n=30) and the Pattern Sequence Learning Test (n=20). Word-stem Priming includes recall, recognition (declarative) and priming (non-declarative) components of memory. The schizophrenia patients demonstrated an impaired performance on recall of words with relative improvement during the recognition portion of the test. Furthermore, they performed normally on the priming portion of the test. Thus, on tests of declarative memory, the patients had retrieval deficits with intact performance on the non-declarative memory component. The Pattern Sequence Learning Test utilizes a serial reaction time paradigm to assess non-declarative memory. The schizophrenia patients' serial reaction time was significantly slower than that of comparison subjects. However, the patients' rate of acquisition was not different from the normal comparison group. The data suggest that patients with schizophrenia process more slowly than normal, but have an intact non-declarative memory. The schizophrenia patients' dissociation on declarative vs. non-declarative memory tests is discussed in terms of possible underlying structural impairment.     

Extent and neural basis of semantic memory impairment in mild cognitive impairment

An increasing number of studies indicate that semantic memory is impaired in mild cognitive impairment (MCI). However, the extent and the neural basis of this impairment remain unknown. The aim of the present study was: 1) to evaluate whether all or only a subset of semantic domains are impaired in MCI patients; and 2) to assess the neural substrate of the semantic impairment in MCI patients using voxel-based analysis of MR grey matter density and SPECT perfusion. 29 predominantly amnestic MCI patients and 29 matched control subjects participated in this study. All subjects underwent a full neuropsychological assessment, along with a battery of five tests evaluating different domains of semantic memory. A semantic memory composite Z-score was established on the basis of this battery and was correlated with MRI grey matter density and SPECT perfusion measures. MCI patients were found to have significantly impaired performance across all semantic tasks, in addition to their anterograde memory deficit. Moreover, no temporal gradient was found for famous faces or famous public events and knowledge for the most remote decades was also impaired. Neuroimaging analyses revealed correlations between semantic knowledge and perirhinal/entorhinal areas as well as the anterior hippocampus. Therefore, the deficits in the realm of semantic memory in patients with MCI is more widespread than previously thought and related to dysfunction of brain areas beyond the limbic-diencephalic system involved in episodic memory. The severity of the semantic impairment may indicate a decline of semantic memory that began many years before the patients first consulted.     

Patterns of verbal memory performance in mild cognitive impairment, Alzheimer disease, and normal aging.

OBJECTIVE: Individuals with mild cognitive impairment (MCI) typically demonstrate memory loss that falls between normal aging (NA) and Alzheimer disease (AD), but little is known about the pattern of memory dysfunction in MCI. METHOD: To explore this issue, California Verbal Learning Test (CVLT) performance was examined across groups of MCI, AD, and NA. RESULTS: MCI subjects displayed a pattern of deficits closely resembling that of AD, characterized by reduced learning, rapid forgetting, increased recency recall, elevated intrusion errors, and poor recognition discriminability with increased false-positives. MCI performance was significantly worse than that of controls and better than that of AD patients across memory indices. Although qualitative analysis of CVLT profiles may be useful in individual cases, discriminant function analysis revealed that delayed recall and total learning were the best aspects of learning/memory on the CVLT in differentiating MCI, AD, and NA. CONCLUSIONS: These findings support the position that amnestic MCI represents an early point of decline on the continuum of AD that is different from normal aging.     

Profiles of Patients with Left Prefrontal and Left Temporal Lobe Lesions after Cerebrovascular Infarcations on California Verbal Learning Test-Like Indices

We compared memory disorders of three patient groups suffering from brain lesions with a word list corresponding to the California Verbal Learning Test (CVLTgcor). Dependent measures were learning rate and efficiency, retention, and strategic control of the learning process. Compared to a control group of patients with right hemispheric lesions, a left Arteria cerebri posterior (LACP) group showed general memory deficits, an inflated recency effect, and increased serial clustering. A left prefrontal cortex (LPFC) group documented slowed learning and increased recall after semantic cues. Discriminant analysis correctly classified 86.11% of the patients. It is argued that (a) the CVLT helps to cover differences in memory disorders recently discussed in cognitive neuropsychology; (b) differences between PFC and ACP patients become evident only if strategic aspects of learning and increased recall after semantic cueing are taken into account. The results are discussed within the framework of recent cognitive neuropsychological findings and with a distinction between fronto-subcortical and cortical memory disorders.     

Profiles of patients with left prefrontal and left temporal lobe lesions after cerebrovascular infarcations on California Verbal Learning Test-like indices

We compared memory disorders of three patient groups suffering from brain lesions with a word list corresponding to the California Verbal Learning Test (CVLTgcor). Dependent measures were learning rate and efficiency, retention, and strategic control of the learning process. Compared to a control group of patients with right hemispheric lesions, a left Arteria cerebri posterior (LACP) group showed general memory deficits, an inflated recency effect, and increased serial clustering. A left prefrontal cortex (LPFC) group documented slowed learning and increased recall after semantic cues. Discriminant analysis correctly classified 86.11% of the patients. It is argued that (a) the CVLT helps to cover differences in memory disorders recently discussed in cognitive neuropsychology; (b) differences between PFC and ACP patients become evident only if strategic aspects of learning and increased recall after semantic cueing are taken into account. The results are discussed within the framework of recent cognitive neuropsychological findings and with a distinction between fronto-subcortical and cortical memory disorders.     

Evidence for impaired encoding and retrieval memory profiles in Parkinson disease.

OBJECTIVE: The purpose of the study was to determine whether patients with Parkinson disease (PD) demonstrate different memory profiles. Specifically, we sought to ascertain whether the memory performance of PD patients can be categorized as fitting an unimpaired, an impaired retrieval, or an impaired encoding memory profile. BACKGROUND: Cognitive impairment in PD is usually described as subcortical-frontal in nature. However, neuropathophysiological changes consistent with diffuse cortical disease are also reported. Establishing memory subtypes in PD could potentially assist in reducing the observed heterogeneity of disease presentation, establishing prognosis, making clinical decisions, and defining endpoints in clinical trials. METHODS:: A sample of 63 PD patients was evaluated with the Hopkins Verbal Learning Test-Revised (HVLT-R). Cluster analysis was used to classify patients into three memory subgroups based on performance on free recall, intrusion errors, and recall enhancement with recognition. Subgroup comparisons were made for demographic and clinical characteristics. RESULTS: An "unimpaired" group (n = 30) demonstrated intact free recall and few intrusion errors. "Impaired retrieval" (n = 22) and "impaired encoding" (n = 11) subgroups with similar impairment on free recall were also identified, but the impaired retrieval group demonstrated greater memory improvement with recognition (P < 0.001) and had fewer intrusion errors (P < 0.001) than the impaired encoding group. CONCLUSIONS: A majority of PD patients demonstrate memory impairment, which can be categorized as either a primary retrieval or a primary encoding deficit. Further research is needed to confirm memory subtypes in PD and determine their diagnostic, prognostic, and therapeutic significance.     

Episodic and semantic memory in mild cognitive impairment

Little is known about episodic and semantic memory in the early predementia stage of Alzheimer's disease (AD), which is referred to as mild cognitive impairment (MCI). To explore person knowledge, item recognition and spatial associative memory, we designed the Face Place Test (FPT). A total of 75 subjects participated: 22 patients with early AD, 24 with MCI and 29 matched controls. As predicted, AD patients showed significant deficits in person naming, item recognition and recall of spatial location (placing). Surprisingly, subjects with MCI were also impaired on all components. There was no significant difference between AD and MCI except on the placing component. Analysis of the relationship between semantic (naming) and episodic (recognition and placing) components of the FPT revealed a significant association between the two episodic tasks, but not between episodic and semantic performance. Patients with MCI show deficits of episodic and semantic memory. The extent of impairment suggests dysfunction beyond the medial temporal lobe. The FPT might form the basis of a sensitive early indicator of AD.     

2型糖尿病患者轻度认知功能障碍的临床分析

目的探讨2型糖尿病患者轻度认知功能障碍的特点。方法将122例2型糖尿病患者分为伴2型糖尿病轻度认知功能障碍组(45例)、不伴2型糖尿病轻度认知功能障碍组(41例)和对照组(36例),使用蒙特利尔认知评估量表(montreal cognitive assessme,MoCA)对患者的命名、注意、视空间/执行功能、持续注意、语言、计算、抽象、定向力、延迟回忆进行评分评估。结果与对照组比较,伴2型糖尿病轻度认知功能障碍组在命名、注意、视空间/执行功能、持续注意、语言、计算、抽象、定向力、延迟回忆等评分比较差异具有统计学意义(P0.01)。与不伴2型糖尿病MCI组比较,伴2型糖尿病MCI组在总分、视空间/执行功能、注意、持续注意、延迟回忆等评分2组间差异有统计学意义(P0.05)。结论伴2型糖尿病的MCI患者在命名、注意、视空间/执行功能、持续注意、语言、计算、抽象、定向力、延迟回忆等方面有不同程度的损害;其总体认知功能损害较不伴2型糖尿病者严重,尤其在视空间/执行能力、注意、持续注意及记忆方面。     

Does impaired executive functioning differentially impact verbal memory measures in older adults with suspected dementia?

The purpose of this study was to examine whether executive dysfunction differentially impacts list-learning and story recall tasks in a sample of older adults referred for suspected cognitive impairment. Older adults (N = 61) with mild cognitive impairment (MCI) or probable mild dementia, and those who did not meet criteria for diagnosis of dementia, were assessed using measures of executive function and verbal memory. Two groups were established based on performance on measures of executive function: (a) the No Executive Dysfunction group (NoED; n = 33) consisted of persons without impairment on any obtained measures of executive function; and (b) the Executive Dysfunction group (ED; n = 28) contained persons with impairment on at least one of the measures of executive function. The two groups were compared on performance on two measures of verbal memory, the California Verbal Learning Test-II (CVLT-II) and the Logical Memory (LM) subtest from the Wechsler Memory Scale-Revised (WMS-R). The NoED group performed significantly better than the ED group on the total learning and short delay free recall trials of the CVLT-II. However, there were no significant differences between the groups on the other indices of the CVLT-II (i.e., long delay free recall, recognition, recall repetitions, recall intrusions, or recognition false-positives) or on the immediate and delayed recall trials of the LM measure. These results support previous research demonstrating the impact of executive dysfunction on the acquisition of and short-delay retrieval of verbal information in older adults with suspected cognitive impairment.     

Group therapy for memory impaired patients: A partial remediation is possible

BACKGROUND AND PURPOSE: To analyse the prospect of memory training for patients with organic brain damage. METHODS: Sixty-two patients with memory disorder were assigned to three different groups: a control group (n=16) with low dose memory training, a process oriented memory training group (POT) (n=24) and a group (ST) who was taught to compensate for memory problems with different strategies (n=22). Most of the patients had suffered a stroke. Inclusion criteria were medium to weak memory impairment defined by the patients' performance in the California Verbal Learning Test. Patients with complete amnesia were excluded. Specific care was taken that the groups did not differ in age, time since illness, duration of rehabilitation effort, verbal and performance IQ, memory and attention performance. The two treatment groups received 20 hours memory training, the low dose memory training control group 7 sessions. RESULTS: The treatment groups improved in verbal and prospective memory, but only the group with POT experienced a significant improvement compared with the control group. Training effects were specific, i. e. they affected verbal memory, but were not encapsulated, i. e. generalized to the recall of prose passages and of appointments. The POT group also showed a statistically weak outperformance compared with the ST group and some attentional improvement as well. CONCLUSION: Memory training is effective in patients with organic brain lesion, but only if applied frequently. Comparing the two training high intensity treatments, a POT focus seems to be superior to teaching a set of compensation strategies.     

Comparison between the story recall test and the word-list learning test in Korean patients with mild cognitive impairment and early stage of Alzheimer's disease

Among verbal memory tests, two that are commonly used to measure the ability of verbal memory function in cognitive impairment are story recall tests and word-list learning tests. However, research is limited regarding which test might be more sensitive in discriminating between normal cognitive aging and patients with Alzheimer's disease (AD) in the Korean population. The purpose of the current study was to compare the word-list learning test (Seoul Verbal Learning Test; SVLT) and the story recall test (Korean Story Recall Test; KSRT) to determine which test is more sensitive in discriminating between individuals with normal cognitive aging and patients with mild cognitive impairment (MCI) and early stage of AD in Korea. A total of 53 healthy adults, 127 patients with MCI, and 72 patients with early stage of AD participated in this study. The receiver-operating characteristic (ROC) curve and area under the curve (AUC) were evaluated to compare these two tests. The results showed that the AUC of the SVLT was significantly larger than the AUC of the KSRT in all three groups (healthy adults vs. MCI and early stage of AD; healthy adults vs. MCI; healthy adults vs. early stage of AD). However, in comparison of patients with MCI and early stage of AD, the AUC of SVLT and the AUC of KSRT were not significant. The word-list learning test is a more useful tool for examining verbal memory function for older adults in Korea than the story recall test.