Inductive reasoning in Alzheimer's disease

We evaluated knowledge of basic level and superordinate semantic relations and the role of cognitive resources during inductive reasoning in probable Alzheimer's disease (AD). Nineteen mildly demented AD patients and 17 healthy control subjects judged the truthfulness of arguments with a premise and a conclusion that contain familiar concepts coupled with "blank" predicates, such as "Spiders contain phosphatidylcholine; therefore all insects contain phosphatidylcholine." Like healthy control subjects, AD patients were relatively insensitive to the typicality of the premise category when judging the strength of arguments with a conclusion containing a basic-level concept, but were relatively sensitive to typicality during judgments of arguments containing a superordinate in the conclusion. Moreover, AD patients resembled control subjects in judging arguments with an immediate superordinate in the conclusion compared to arguments with a distant superordinate. AD patients differed from control subjects because they could not take advantage of two premises in an argument containing basic-level concepts. We conclude that semantic knowledge is sufficiently preserved in AD to support inductive reasoning, but that limited cognitive resources may interfere with AD patients' ability to consider the entire spectrum of information available during semantic challenges.

Clinical and pathological diagnosis of frontotemporal dementia: report of the Work Group on Frontotemporal Dementia and Pick's Disease

An international group of clinical and basic scientists participated in the Frontotemporal Dementia and Pick's Disease Criteria Conference at the National Institutes of Health in Bethesda, Md, on July 7, 2000, to reassess clinical and neuropathological criteria for the diagnosis of frontotemporal dementia (FTD). Previous criteria for FTD have primarily been designed for research purposes. The goal of this meeting was to propose guidelines that would enable clinicians (particularly neurologists, psychiatrists, and neuropsychologists) to recognize patients with FTD and, if appropriate, to expedite their referral to a diagnostic center. In addition, recommendations for the neuropathological criteria of FTD were reviewed, relative to classical neuropathology and modern molecular biology.

A model for individual egg production in chickens

Our primary objective was to improve on an existing model for the individual weekly egg production curve by modeling the curve as a sum of logistic functions: one for the increasing phase of production and a sum for the decreasing phases. To illustrate the model, we used four data sets from two pairs of individuals. For these data, the model consisted of an increasing phase and a single decreasing phase of production: y(t) = m k1((1 - e(-t))/(1 + e(-t))) - m(k1 - k2)((1 - e(-t))/(1 + e(-(t-c2)))) where y(t) is egg production at week t, m is maximum production during a specific time interval, k1 is proportion of maximum production for the increasing phase, k2 is proportion of maximum production for the decreasing phase, and c2 is point of inflection from the upper level of the increasing phase to the lower level of the decreasing phase; thus, c2 is a measure of persistency of egg production. For one pair of individuals, production was about 88% of maximum (k1) for the increasing phase and about 76% of maximum (k2) for the decreasing phase. For the other pair, production was about 91% of maximum (k1) for the increasing phase and about 75% of maximum (k2) for the decreasing phase. Persistency (c2) was about 25 wk for one pair and about 28 wk for the other. Predicted total 52-wk production was within one or two eggs of actual production. The secondary objective was to improve estimation of model parameters by summarizing egg production data by 1-wk, 2-wk, or 4-wk intervals and by using cumulative egg production instead of weekly production. For weekly production, estimates of parameters changed only slightly, as intervals increased from 1 wk to 2 wk or to 4 wk. Predicted total 52-wk production, however, decreased up to five eggs as interval increased from 1 wk to 4 wk. For cumulative egg production by time t, Yt, the model was Yt = 7 k1[2 Ln((1 + e(t))/2) - t] - 7(k1 - k2)[(1 + e(-2)2) Ln((e(c2) + e(t))/(1 + e2c)) - te(-c2)]. For cumulative production, estimates of parameters changed only slightly, if at all, as intervals increased from 1 wk to 4 wk. Predicted 52-wk production, however, approached the actual number as interval increased from 1 wk to 4 wk. Prediction of annual (52-wk) egg production based on part-record production for only the first 22 wk might lead to over-prediction because persistency of production lasted longer than the part record. Genetic gain from selection to improve annual production, therefore, might be increased if selection accounted for persistency of production and for the multiphasic shape of the individual egg production curve, and if data were summarized by 4-wk intervals and cumulated.

Clinical testing results and high patient satisfaction with a new needle-free device for growth hormone in young children

Fifty children ages 4-10 yr with type 1 diabetes mellitus volunteered to participate in a study to evaluate and compare a new needle-free device developed for growth hormone delivery. Children answered descriptive questions related to nervousness and worry, hurt or pain, redness or bleeding, and stinging and wetness. Choices for answers for each of these five questions were none, a little, or a lot. None or a little was also combined to give a minimal category. Children also answered four questions that compared the needle-free device to their morning insulin needle injection in reference to ease of use, pain, nervousness, and overall preference. Half the children had single comfort rings inserted to increase the injection pressure. Results indicated no difference in question responses with or without pressure rings. Pain (92%), erythema (96%), worry (90%), stinging (86%) and wetness (96%) were minimal and significant (0.001 > p < 0.03) following all questions. Results of the comparative questionnaire indicated that the device was easier (p < 0.03) to use than needles and significantly preferred (p < 0.001) in 74% of children under age 10.

Effect of hatch on the distribution for failure of an embryo to survive incubation

The objectives of this paper were to validate an improved model to describe failure to hatch by using data obtained from two hatches of a line of chickens and to examine the effect of hatch on the distribution for time of failure of an embryo to survive incubation. Breakout analysis of 11,254 eggs that failed to hatch was used to characterize the distribution for time of failure to survive and the probability of failure to hatch. The distribution for time of failure to survive was modeled by a diphasic Weibull distribution, corresponding to the two phases of increased embryonic mortality during incubation. Distribution parameters for time of failure to survive were estimated by maximum likelihood and minimum Hellinger distance. Goodness-of-fit statistics validated the appropriateness of the diphasic Weibull distribution. Overall, the proportion of infertility was 0.213, and the proportion of embryonic mortality by the end of incubation was 0.086. Among embryos that suffered mortality during incubation, the proportion that died during Phase 1 was 0.77; therefore, 0.23 died during Phase 2. For Phase 1, mean time of mortality was 2.6 d, and standard deviation was 3.3 d. For Phase 2, mean time was 17.4 d, and standard deviation was 2.0 d. Time of mortality was distributed differently in the two hatches; this difference occurred mostly during Phase 1. Failure rates of the two hatches were different during the first 3 d of incubation. The model is useful to assess probability of failure to hatch and the distribution for time of failure to survive during incubation.

Missed and associated injuries after subtalar dislocation: the role of CT

Subtalar joint dislocation (STJD) is an uncommon injury, but carries with it a potential for significant functional disability. We hypothesized that a significant number of injuries associated with subtalar joint dislocation may be unrecognized by plain radiographic examination. Therefore, we reviewed the records of all STJDs over a three-year period, identifying nine cases. The majority of injuries occurred in men (78%) with a mean age of 29 years. Overall, the mean age at injury was 32 years. The right lower extremity was most frequently injured (87.5%). Plain films initially diagnosed a STJ dislocation in all patients. A CT scan was performed in all cases. In 100% of patients, CT identified additional injuries missed on initial plain radiographs. In 44% of patient, new information gathered by CT dictated a change in treatment. Based on our findings, we conclude that CT is an invaluable tool to assess for associated injuries in STJ dislocation, and should be performed in all cases of STJ dislocation.

A nonlinear model for mammary gland growth and regression in lactating sows

The objective was to propose an empirical mathematical model to describe mammary gland growth and regression in lactating sows. A nonlinear dynamic model based on the logistic function was constructed, and data from 61 sows were used to illustrate the model. Sows were fed four diets with two levels of energy and of protein during lactation, and individuals were slaughtered over a 30-d period to produce a cross sectional data set on weight and composition variables from suckled mammary glands. Data (y(x)) were obtained for each day of lactation (x) and fitted by nonlinear regression. The logistic distribution function was modified for different durations of growth (f; days/gram of weight or composition) and regression (g; days/gram of weight or composition): [formula in text] where y(max) is maximum weight or composition and x(max) is day of lactation at maximum. Based on results for wet weight, for example, individually suckled mammary glands grow until between Day 21 and 28 of lactation and reach a maximum of about 500 to 600 g, depending on diet. Growth pattern of mammary glands can be described well with an asymmetric nonlinear model, using different durations for growth and regression. From this model, it was possible to estimate directly biologically important parameters: maximum weight or composition, day of lactation at maximum weight or composition, and durations of growth and regression. This model can be applied to describe mammary gland growth patterns for other species and to describe similar growth or production patterns.

A rule-based categorization deficit in Alzheimer's disease?

This study examined the categorization processes that Alzheimer's disease (AD) patients use during assessments of semantic memory. Rule-based categorization involves the careful, analytic processing of strict criteria to determine category membership, particularly for items from graded categories with ambiguous category membership; similarity-based categorization requires an overall comparison of a test stimulus with a prototype or remembered exemplar of the category and is relatively effective for the rapid categorization of items with unambiguous category membership. To assess these processes in AD, patients were asked to decide the category membership of test stimuli for categories with poorly defined or fuzzy boundaries (e.g., VEGETABLE) and for categories with well-defined boundaries (e.g., FEMALE) and then to judge the representativeness of the test stimulus for its chosen category. A subgroup of AD patients demonstrated a typical pattern of impaired semantic memory compared to healthy control subjects; that is, difficulty deciding the category membership of test items from fuzzy categories. Among these patients, we found no deficit in category membership decisions about items taken from well-defined categories. We also found that AD patients and healthy controls do not differ in their representativeness judgments of items within a correctly judged category. These findings are most consistent with the hypothesis that rule-based categorization difficulty limits semantic memory in AD.

Dopamine supports sentence comprehension in Parkinson's Disease

OBJECTIVE

To determine the role of dopamine in the executive resource component of sentence comprehension.

METHODS

We studied sentence-picture matching in 20 right-handed, non-demented, native English speakers with mild Parkinson's disease (PD) when 'on' and 'off' their levodopa, taking into account disease duration to control for endogenous dopamine metabolism. We also administered a verbal working memory measure that does not involve specific grammatical manipulations.

RESULTS

PD patients 'off' levodopa demonstrated a significant discrepancy in their comprehension of grammatically complex sentences compared to grammatically simpler sentences that was not evident when PD patients were 'on' levodopa. An error analysis demonstrated that impaired comprehension of grammatically complex sentences when 'off' levodopa was associated with poorer performance on foils requiring working memory resources. Performance on an independent measure of verbal working memory correlated only with comprehension of grammatically complex sentences during levodopa supplementation, but working memory according to this measure did not differ during 'on' and 'off' states.

CONCLUSION

Dopamine supports the executive resources contributing to sentence comprehension in PD.

Frequency of tau gene mutations in familial and sporadic cases of non-Alzheimer dementia

BACKGROUND

Mutations in the tau gene have been reported in families with frontotemporal dementia (FTD) linked to chromosome 17. It remains uncertain how commonly such mutations are found in patients with FTD or non-Alzheimer dementia with or without a positive family history.

OBJECTIVE

To determine the frequency of tau mutations in patients with non-Alzheimer dementia.

PATIENTS AND METHODS

One hundred one patients with non-Alzheimer, nonvascular dementia, most thought to have FTD. Of these, 57 had a positive family history of dementia. Neuropathologic findings were available in 32. The tau gene was sequenced for all exons including flanking intronic DNA, portions of the 3' and 5' untranslated regions, and at least 146 base pairs in the intron following exon 10.

RESULTS

Overall, the frequency of the tau mutations was low, being 5.9% (6/101) in the entire group. No mutations were found in the 44 sporadic cases. However, 6 (10.5%) of the 57 familial cases and 4 (33%) of the 12 familial cases with tau pathologic findings had mutations in the tau gene. The most common mutation was P301L.

CONCLUSIONS

We conclude that tau mutations are uncommon in a neurology referral population with non-Alzheimer dementia, even in those with a clinical diagnosis of FTD. However, a positive family history and/or tau pathologic findings increase the likelihood of a tau mutation. There must be other genetic and nongenetic causes of FTD and non-Alzheimer dementia, similar to the etiologic heterogeneity present in Alzheimer disease.

Loss of brain tau defines novel sporadic and familial tauopathies with frontotemporal dementia

Dementia lacking distinctive histopathology (DLDH) or frontotemporal lobe degeneration (FTLD) is the most common neuropathological diagnosis for sporadic frontotemporal dementias (FTDs). The hallmarks of DLDH are neuron loss and gliosis in the absence of any disease-specific brain lesion. Similar brain pathology is also seen in a familial FTD pedigree known as hereditary dysphasic disinhibition dementia 2 (HDDD2). Abnormality in the function or isoform composition of the microtubule binding protein tau is a prominent feature in the brains of many patients with sporadic and hereditary FTDs. Therefore, we studied the tau protein in different brain regions from DLDH and HDDD2 patients. Our results indicate that a selective loss of all six tau isoforms, but not tau mRNA, occurs in these brains compared to normal control and Alzheimer's disease brains. Loss of tau protein was identified by Western blot analysis of protein extracts from DLDH and HDDD2 brains in regions both with and without neuronal degeneration. Functionally, this loss of tau protein may be equivalent to pathogenic mutations in the tau gene identified in familial FTD with parkinsonism linked to chromosome 17 (FTDP-17). Thus, DLDH and HDDD2 are novel tauopathies with a unique mechanism of pathogenesis. The presence of tau mRNA in these brains suggests that the level of tau protein may be controlled posttranscriptionally, at the level of either translation or mRNA stability.

Progressive peripheral agraphia

We describe RW, a patient who presented with writing difficulty that deteriorated over time. While her graphemes were typically legible, her writing was extremely slow, and her letters were written in an inconsistent and heterogeneous manner (e.g. each "a" in the word "banana" was produced in a different way). Her mental imagery of letters was impoverished, and she also produced allographic errors in her writing. She had some spelling errors as well, but many of these were due to omissions, perseverations, and motor operations. A positron emission tomography scan demonstrated superior parietal occipital and superior frontal defects that were more evident on the left than the right. Our observations are consistent with the hypothesis that RW has a deficit retrieving physical letter forms as manifested by her heterogeneous and slow production of letter forms. This disruption of grapheme retrieval is associated with interruption of a superior frontal-parietal system in the left hemisphere.

Verb comprehension in frontotemporal degeneration: the role of grammatical, semantic and executive components

Verb comprehension has been associated with the left frontal cortex, but assessments of verb comprehension in frontotemporal degeneration (FTD) have been rare. This study assessed word-picture matching for verbs and nouns under two conditions: alone (baseline) and during concurrent performance of a secondary task. In addition, we correlated FTD patients' verb comprehension with their performance on measures of executive resources and language. We found that FTD patients were significantly less accurate and required significantly longer to make word-picture matching decisions about verbs compared with nouns at baseline. During concurrent performance of a secondary task, accuracy decreased and response latencies became prolonged for nouns to the point that these measures equaled the performance with verbs at baseline. Verb comprehension accuracy was significantly correlated with the performance on executive measures such as category naming fluency, the Stroop test, and the Trail Making Test Part B (Trails B test). Assessment of FTD patient subgroups revealed distinct profiles of performance, suggesting that several factors contribute to verb comprehension in FTD. Verb comprehension in FTD patients with a dysexecutive syndrome (EXEC, n = 10) was sensitive to concurrent performance of a secondary task, and their verb comprehension accuracy correlated with the time required to complete executive measures such as the Stroop test and the Trails B test. This suggested a relationship between impaired verb comprehension and limited information-processing speed in EXEC patients. Verb comprehension in patients with a progressive non-fluent aphasia (PNFA, n = 7) was not selectively influenced by executive resources. Instead, verb comprehension accuracy in PNFA was significantly correlated with sentence comprehension accuracy, suggesting that grammatical aspects of verbs play a crucial role in their verb comprehension difficulty. Although we studied only a small number of patients with semantic dementia (SD, n = 4), we observed significant verb comprehension difficulty that was minimally influenced by executive resources and was unrelated to sentence comprehension. It is possible that impaired verb comprehension in SD is related in part to the degradation of semantic feature knowledge.

A model for persistency of egg production

The objectives of our study were to propose a new definition for persistency of egg production and to develop a mathematical model to describe the egg production curve, one that includes a new measure for persistency, based on the proposed definition, for use as a selection criterion to improve total egg production. Persistency of egg production is an important determining factor for total egg production. Hens with the same total production, however, can exhibit different egg production curves because of differences in persistency. We propose a new definition for persistency of egg production: the number of weeks during which a level of constant production is maintained. No egg production model exists that includes a measure of persistency in terms of duration of time or that allows this measure of persistency to be derived from model parameters. It was necessary, therefore, to develop a new model to describe an egg production curve for a flock: equation [see text] and for an individual: equation [see text] where y(t) = egg production at time t, t1 and t2 = times at transition, r = duration of transition, y(p) = level of constant production, b4 = rate of decline in production, and P = persistency of constant production. These parameters measure directly the important biological characteristics of an egg production curve. To illustrate the model, six data sets were used: two from flocks (one pullet flock and one hen flock) and four from two pairs of individuals. The proposed definition of persistency should be important for genetic selection because it might be desirable to select for increased persistency. The novel approach to the definition and measure of persistency presented here should provide a better understanding of the relationship between the new measure of persistency and other characteristics of egg production.

Quantitative neurohistological features of frontotemporal degeneration

Frontotemporal degeneration (FTD) is a neurodegenerative condition that has been principally associated with frontal lobe dementia. In this study, we compared neuropathological abnormalities in frontal, hippocampal, and calcarine cortices from patients assigned a diagnosis of FTD, normal elderly and Alzheimer's disease (AD). Densities of Nissl-stained neurons and lesions which were immunolabeled for tau, beta-amyloid (Abeta), alpha- and beta-synuclein, ubiquitin, glial fibrillary acidic protein (GFAP) and CD68 antigen were determined using computer-assisted, non-biased quantitative microscopy. We found that FTD frontal and hippocampal regions exhibited marked neuron loss, abundant ubiquitin-immunoreactive (ir) dystrophic neurites, GFAP-ir astrocytes, and CD68-ir microglia, while calcarine cortex was spared. No alpha- or beta-synuclein-ir lesions were observed, and neither the density of tau-ir neurofibrillary tangles nor that of Abeta-ir plaques in FTD exceeded normal controls. In addition, there were no neuropathological differences between FTD subjects who presented clinically with a frontal lobe dementia versus an AD-like dementia. These findings indicate that FTD is a category of neurodegnerative dementias with varying clinical presentations that is characterized by the progressive degeneration of select populations of cortical neurons. The molecular neurodegenerative mechanisms that lead to FTD remain to be elucidated.

Immunohistochemical and biochemical studies demonstrate a distinct profile of alpha-synuclein permutations in multiple system atrophy

Although alpha-synuclein (alpha-syn) has been implicated as a major component of the abnormal filaments that form glial cytoplasmic inclusions (GCIs) in multiple system atrophy (MSA), it is uncertain if GCIs are homogenous and contain full-length alpha-syn. Since this has implications for hypotheses about the pathogenesis of GCIs, we used a novel panel of antibodies to defined regions throughout alpha-syn in immunohistochemical epitope mapping studies of GCIs in MSA brains. Although the immunostaining profile of GCIs with these antibodies was similar for all MSA brains, there were significant differences in the immunoreactivity of the alpha-syn epitopes detected in GCIs. Notably, carboxy-terminal alpha-syn epitopes were immunodominant in GCIs, but the entire panel of antibodies immunostained cortical Lewy bodies (LBs) in dementia with LBs brain with similar intensity. While the distribution of alpha-syn labeled GCIs paralleled that previously reported using silver stains, antibodies to carboxy-terminal alpha-syn epitopes revealed a previously undescribed burden of GCIs in the MSA hippocampal formation. Finally, Western blots demonstrated detergent insoluble monomeric and high-molecular weight alpha-syn species in GCI rich MSA cerebellar white matter. Collectively, these data indicate that alpha-syn is a prominent component of GCIs in MSA, and that GCIs and LBs may result from cell type specific conformational or post-translational permutations in alpha-syn.

Oral reading in dementia

Reading has been thought to consist of three main processing components: the orthographic, phonological, and semantic lexicons. In traditional psycholinguistic models, these components have been treated independently such that the selective dysfunction of one does not necessarily imply the breakdown of another. Recently, it has been proposed that a word's semantic representation is essential to oral reading such that a disturbance within the semantic lexicon will disrupt processing within the orthographic and/or phonological lexicons. From this view, semantic deterioration should lead to fragmentation of the other systems contributing to reading, resulting in a specific pattern of errors during oral reading. This would include (1) a larger than normal advantage for reading words with regular spelling-to-sound correspondence over words with exception spelling, as well as the production of "regularization errors" when reading exception words; and (2) a smaller than normal difference between reading real words and pronounceable nonwords, or pseudowords (PW's). We found that patients with Semantic Dementia generally conformed to these hypothesized patterns of reading difficulty. Despite the presence of a semantic impairment, however, patients with Alzheimer's Disease, Frontotemporal Dementia, and Progressive Non-Fluent Aphasia did not demonstrate these patterns of reading difficulty. Our findings suggest that not all semantic impairments invariably lead to the disruption of the orthographic and phonological lexicons.

Regional cerebral distribution of [Tc-99m] hexylmethylpropylene amineoxine in patients with progressive aphasia

Progressive aphasia is a prominent clinical feature of several neurodegenerative disorders. This study used hexylmethylpropylene amineoxine (HMPAO) single photon emission computed tomography (SPECT) to estimate blood flow in areas of the brain that mediate language in patients with progressive aphasia and matched control subjects. The patient population consisted of four men and 12 women with a mean +/- SD age of 69.1 +/- 7.6. Of these, eight were classified as having a nonfluent form of aphasia, whereas the other eight had a fluent form. The patients were compared to 16 healthy volunteers who were studied with an identical protocol. The SPECT images of the brain were acquired with 740 MBq (20 mCi) of Tc-99m-labeled HMPAO on a triple-headed gamma camera equipped with fan beam collimators. The images were analyzed with a set of standardized templates. Mean counts per pixel in 33 regions of interest were compared to the mean counts in the whole supratentorial brain. A laterality index was determined for homotopic regions using the equation 100 x (R - L)/(1/2 x (R - L)). Patients with progressive aphasia had several regions of significantly decreased HMPAO uptake in the left cortex when compared to the homotopic regions on the right. The most prominent deficit in the nonfluent group, as determined by the laterality index, were found in the left dorsolateral prefrontal region (p < 0.05), whereas the most prominent deficits in the group with fluent aphasia were found in the left temporal and parietal language centers (p < 0.05). The left subcortical nuclei were differentially affected, particularly in patients with nonfluent aphasia. The HMPAO SPECT indicates that multiple regions of the left hemisphere are dysfunctional in patients with progressive aphasia. The pattern of perfusion deficits in patients with fluent aphasia appears to be distinct from the pattern in patients with nonfluent aphasia.

Cognitive resource limitations during sentence comprehension in Parkinson's disease

Patients with idiopathic Parkinson's disease (PD) were asked to identify the agent of the action in orally presented sentences with subject-relative or object-relative center-embedded clauses while simultaneously performing a secondary task that was less resource-demanding (finger tapping) or more resource-demanding (recognition span). We found that a subgroup of PD patients with impaired sentence comprehension at baseline (no secondary task) did not differ from random in their accuracy understanding all types of sentences during the more demanding (recognition span) condition and also had difficulty understanding the most complex sentences during the less demanding (finger tapping) condition. Control subjects and PD patients without baseline sentence comprehension difficulty were random only in their comprehension of the most complex sentences under the more demanding (recognition span) secondary task condition. Examination of response latencies for accurately understood sentences revealed only an effect for the type of sentence, and this was equally evident across all groups of subjects and regardless of the condition under which the sentences were administered. The sensitivity of PD patients' sentence comprehension accuracy to secondary task resource demands is most consistent with the hypothesis that limited cognitive resources contribute to sentence comprehension difficulty in PD.

Adverse dermatologic effects of cardiovascular drug therapy

Cardiovascular disease is common, affecting an increasing number of persons as the population ages. To combat this growing health problem, physicians use a multitude of medications in the treatment of their patients. Although pharmacologic therapy greatly enhances quality of life for a majority of patients, there is always the potential for an unfavorable reaction. For example, cardiovascular drugs can induce a vast array of adverse dermatologic responses. This article reviews the various cutaneous reaction patterns that can occur as a result of treatment with specific cardiovascular agents.

Response of males and females to high-force eccentric exercise

It has previously been shown that females incur less muscle damage than males after strenuous exercise, but limited data are available for humans. To determine possible differences between the sexes in humans, the response to high-force eccentric exercise was examined in a large sample of women (n = 83) and men (n = 82). The participants performed a bout of eccentric exercise of the elbow flexors consisting of 70 maximal repetitions. Isometric strength, resting elbow angle and muscle soreness were measured before, immediately after (except soreness) and then daily for 7 days after exercise. There was a significant loss in strength among both groups (69% for women and 63% for men) (P < 0.01) immediately after exercise; at 168 h post-exercise, women still had a 27% strength loss and men had a 24% strength loss. No significant difference in strength loss or recovery rate was found between men and women. Soreness reached peak values 32-48 h post-exercise (P < 0.01), with no significant difference between men and women. Range of motion decreased significantly until 3 days after exercise (14.6 degrees or 0.255 rad loss for women; 12.2 degrees or 0.213 rad loss for men) (P < 0.01); at 168 h post-exercise, the women and men still showed a loss of 4.8 degrees (0.084 rad) and 4.0 degrees (0.07 rad), respectively. There was a significant interaction of sex x time (P < 0.01); a post-hoc test indicated that the women experienced a greater loss in range of motion at 72 h than men and this difference was maintained to 168 h post-exercise (P < 0.01). Thus, our results do not support the contention that women have a lower response to eccentric exercise than men.

Calcinosis cutis following the administration of intravenous calcium therapy

Calcinosis cutis, the cutaneous deposition of calcium salts in the dermis, can occur through a variety of pathogenetic mechanisms, and can be associated with both normal and elevated calcium levels. Iatrogenic causes of calcinosis cutis include extravasation of intravenously administered calcium chloride or calcium gluconate, and traumatic deposition of calcium in the skin, subsequent to electromyography or electroencephalography. We report two cases of calcinosis cutis following intravenous infusion of a calcium-containing salt.

The effects of beer taxes on physical child abuse

The purpose of this paper is to examine the effects of alcohol regulation on physical child abuse. Given the positive relationship between alcohol consumption and violence, and the negative relationship between consumption and price, the principal hypothesis to be tested is that an increase in the price of alcohol will lead to a reduction in the incidence of violence. We also examine the effects of illegal drug prices and alcohol availability on the incidence of child abuse. Equations are estimated separately for mothers and fathers, and include state fixed effects. Results indicate that increases in the beer tax may decrease the incidence of violence committed by females but not by males.

Nutrient flows for poultry production in The Netherlands

Government targets for ammonia emission and for N and P loss per hectare (ha) of agricultural land were used to assess carrying capacity for poultry production in The Netherlands with data from 1990. In addition, the effect of alternative management strategies on carrying capacity was determined. Ammonia emission from poultry production in 1990 [20.5 gigagrams (Gg) N] exceeded the target for 2000 (i.e., 6.9 Gg N). Targets defined for 2000 and 2010 (i.e., 4.6 Gg N) can be achieved, however, without reducing poultry numbers, assuming national introduction of measurements studied. Measures that reduced ammonia emission directly, i.e., introduction of low-emission housing or manure application techniques, were most effective. In 1990, N and P losses equalled 215 kg/ha for N and 31 kg/ha for P. The N loss was slightly lower than the target for 2000 (219 kg N/ha) but exceeded the target for 2010 (144 kg N/ha). Reduction of application of artificial N fertilizer, however, reduced N loss effectively from 215 to 22 kg/ha. National P loss in 1990 exceeded the target for 2000 (15.3 kg P/ha). Reduction of application of artificial P fertilizer reduced P loss most effectively from 31 to 14 kg/ha. To achieve the target for 2010 (8.7 kg P/ha), additional reduction in P excretion by poultry is required. This reduction can be achieved by use of phytase in layer and broiler feed and by use of a coarse Ca source in layer feed. Unlike pig production, carrying capacity for poultry production in The Netherlands is not limited by governmental targets for acidification, eutrophication, or drinking water contamination.

The ABC rule for clinical detection of subungual melanoma

BACKGROUND

Subungual melanoma is a relatively rare disease with reported incidence between 0.7% to 3.5% of all melanoma cases in the general population. Unlike the significant improvement in the diagnosis of cutaneous melanoma, the diagnosis of subungual melanoma has shown little, if any, improvement over the years. The widespread adoption of the ABCDs of cutaneous melanoma has helped increase public and physician awareness, and thus helped increase the early detection of cutaneous melanoma; the same criteria cannot be applied to the examination of the nail pigmentation.

OBJECTIVE

We reviewed the world literature on subungual melanoma and arranged the available information into a system for the identification of subungual melanoma. This system has to be thorough, easy to remember, and easy to apply by both physician and lay public. A case to illustrate the delayed diagnosis often encountered in the current evaluation of nail melanoma is presented.

METHODS

A thorough review of the world literature on subungual melanoma was undertaken. The important findings of various studies and case reports were compared among themselves and the salient features were summarized. The information was then categorized under the easily recalled letters of the alphabet, ABCD, that have already become associated with melanoma.

RESULTS

The most salient features of subungual melanoma can be summarized according to the newly devised criteria that may be categorized under the first letters of the alphabet, namely ABCDEF of subungual melanoma. In this system A stands for a ge (peak incidence being in the 5th to 7th decades of life and African Americans, Asians, and native Americans in whom subungual melanoma accounts for up to one third of all melanoma cases. B stands for brown to black b and with breadth of 3 mm or more and variegated borders. C stands for change in the nail band or lack of change in the nail morphology despite, presumably, adequate treatment. D stands for the digit most commonly involved; E stands for extension of the pigment onto the proximal and/or lateral nailfold (ie, Hutchinson's sign); and F stands for family or personal history of dysplastic nevus or melanoma.

CONCLUSION

Although each letter of the alphabet of subungual melanoma is important, one must use all the letters together to improve early detection and thus survival of subungual melanoma. Still, as with cutaneous melanoma, the absolute diagnosis of subungual melanoma is made by means of a biopsy.

Targeted neuronal death affects neuronal replacement and vocal behavior in adult songbirds

In the high vocal center (HVC) of adult songbirds, increases in spontaneous neuronal replacement correlate with song changes and with cell death. We experimentally induced death of specific HVC neuron types in adult male zebra finches using targeted photolysis. Induced death of a projection neuron type that normally turns over resulted in compensatory replacement of the same type. Induced death of the normally nonreplaced type did not stimulate their replacement. In juveniles, death of the latter type increased recruitment of the replaceable kind. We infer that neuronal death regulates the recruitment of replaceable neurons. Song deteriorated in some birds only after elimination of replaceable neurons. Behavioral deficits were transient and followed by variable degrees of recovery. This raises the possibility that induced neuronal replacement can restore a learned behavior.

Assessment of cerebral blood flow in Alzheimer's disease by spin-labeled magnetic resonance imaging

To evaluate the utility of arterial spin-labeled blood flow magnetic resonance imaging for the detection of cerebral blood flow abnormalities in Alzheimer's disease, arterial spin-labeled blood flow images in 16 contiguous 5-mm axial sections were acquired in 18 patients diagnosed with probable Alzheimer's disease and 11 age-matched controls. Blood flow images from all subjects were transformed to a standard anatomical space for voxel-by-voxel statistical analysis. High quality blood flow images were obtained from all but 1 subject. Statistical analysis demonstrated significant flow decreases relative to control subjects in temporal, parietal, frontal, and posterior cingulate cortices. Increased severity of disease, as measured by Mini-Mental State Examination, correlated with posterior parietal and posterior cingulate decreases but not temporal decreases. Arterial spin-labeled magnetic resonance imaging was found to be an effective tool for characterizing flow decreases accompanying Alzheimer's disease. The absence of ionizing radiation or injection and the ability to obtain high quality anatomical images within the same scanning session make arterial spin labeling an attractive technique for the study of Alzheimer's disease, for the evaluation of pharmacological therapies, and, possibly, for early diagnosis.

MR lesion load and cognitive function in patients with relapsing-remitting multiple sclerosis

BACKGROUND AND PURPOSE

Multiple sclerosis (MS) is a demyelinating disease most often associated with progressive physical impairment; however, its effects are noted to extend beyond physical disability. Our purpose was to determine the relationship between T2 lesion volume and neurocognitive and physical disability in relapsing-remitting multiple sclerosis.

METHODS

We studied a cohort of 19 patients with relapsing-remitting MS. Of this group, there were 15 women and four men from varying socioeconomic backgrounds. This volunteer sample was selected from a larger group of 53 patients with MS in our longitudinal MS study because they had been untreated with any beta-interferon medications, had been followed for at least 12 months, and had a clinical status of relapsing-remitting MS.

RESULTS

Of 12 neurocognitive parameters tested, two correlated significantly with lesion loads. The correlation of the Symbol-Digit Modalities test, which analyzes information-processing speed, was significant (P = .0204). The correlation of the fifth trial of the Rey Auditory Verbal Learning test, which tests verbal long-term memory, was also significant (P = .0348). None of the other 10 neurocognitive examinations, however, showed a significant correlation with total lesion volume (Paced Auditory Serial Addition test-1.6, P = .7381; Paced Auditory Serial Addition test-2.0, P = .4180; Controlled Oral Word Association test, P = .8906; Category Fluency test, P = .4423; Bells test, P = .9097; Rey Auditory Verbal Learning test-delay, P = .9843, Rey Auditory Verbal Learning test-recognition, P = .7467; Word Span test, P = .4939; Road Map test, P = 0.4939). The lesion load also did not correlate with the physical disability scales as rated according to the Expanded Disability Status Scale (P = .68) or Ambulation Index (P = .95).

CONCLUSION

Our results indicate that T2 lesion volume does not seem to be a robust surrogate marker of neuropsychological impairment in patients with MS. We think that global measurements of parameters that are more specific to the disease process may offer more precise correlation with cognitive dysfunction and other disability parameters.

MR imaging quantitation of gray matter involvement in multiple sclerosis and its correlation with disability measures and neurocognitive testing

BACKGROUND AND PURPOSE

Multiple sclerosis (MS) is the most common inflammatory disease of the central nervous system and manifests both physical and neurocognitive disabilities. Although predominantly a disease of the white matter, MS is also characterized by lesions in the gray matter. Previous pathologic studies have found that cortical and deep gray matter lesions comprised 5% and 4%, respectively, of total lesions. Using software for lesion detection and quantitation, our study was designed to determine MS involvement in the cortical and deep gray matter and to correlate gray matter lesion load with neurocognitive function and the Kurtzke Expanded Disability Status Scale.

METHODS

Using a semiautomated segmentation algorithm that detected and delineated all possible brain MS lesions on MR images, we investigated gray matter lesion volume in 18 patients with untreated relapsing-remitting MS. Cortical and deep gray matter lesions then were correlated with the neurocognitive and physical disability measurements.

RESULTS

We found that cortical gray matter lesions comprised approximately 5.7% of the total lesion volume, whereas deep gray matter lesions comprised another 4.6% in this patient cohort. No strong correlations were found between gray matter lesions and disability status or neurocognitive function.

CONCLUSION

These results are similar to those found in previous pathologic studies. The cortical lesion load in cases of relapsing-remitting MS, as measured by MR imaging, represents less than 6% of the total lesion volume and does not correlate with disability measures or neurocognitive tests.

Persistency of lactation yield: a novel approach

The objectives of our study were to propose a new, simple, and easy-to-understand definition for persistency of lactation yield and to develop a new mathematical model to describe a lactation curve, one that includes a measure for persistency of lactation yield according to the proposed definition. Our definition of persistency is the number of days during which the level of constant yield is maintained. No lactation model exists that includes a measure of persistency in terms of duration of time or that allows this measure of persistency to be derived from model parameters. It was necessary, therefore, to develop a new model to describe the lactation curve: [formula: see text] where yt = yield at time t, t1 = time at transition from increased yield to constant yield, yP = level of constant yield, b3 = rate of decline in yield from the end of constant yield to the end of lactation, and P = persistency of constant yield. These four parameters measured directly the important biological characteristics of a lactation curve. Two test day data sets, one for individual records from a high-producing cow and one for average records from 17,607 cows, were used to illustrate the model and to estimate persistency. The proposed measure of persistency should be important for genetic selection because it might be desirable to select for increased persistency (e.g., for extended lactations) without increasing peak yield and, hence, subjecting the cow to undesirable stress.

Sentence processing in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative condition that is associated with the depletion of dopamine (DA)-containing neurons in specific brain regions. This article reviews one consequence of this defect-sentence comprehension difficulty in nondemented patients with PD. The first section describes the pattern of cognitive deficits seen in patients with PD, focusing specifically on their difficulties with language processing. Subsequent sections relate the profile of cognitive impairments in PD to studies investigating compromised DA metabolism in fronto-striatal brain regions. The findings suggest that the sentence comprehension deficit in PD is due in large part to limitations in the strategic distribution of cognitive resources such as selective attention that contribute to the processing of complex material. The physiological basis for this deficit appears to be associated with the disruption of a fronto-striatal cerebral network that is compromised following degradation of the DA projection system.

Emotional distress in critically-injured patients three months after a potentially life-threatening accident

A case-control study was carried out to determine why some critically-injured patients remained emotionally distressed while other critically-injured patients were found to be minimally distressed three months after a potentially life-threatening accidental injury. Cognitive processing and meaning theories suggest that psychological adjustment following a traumatizing event depends on the successful integration of the event into current or modified cognitive schema and the restoration of a sense of meaning in life. These cognitive processes may be facilitated by coping strategies that share concerns, mobilize support and reframe disturbing elements. The Global Severity Index was used to identify critically-injured patients as either emotionally distressed or minimally distressed. Bradburn's Psychological Well-Being Scale, Impact of Events Scale, the Meaning-of-Illness Questionnaire and Family Crisis-Oriented Personal Evaluation Scale were used to collect cross-sectional data from 51 critically-injured patients during face-to-face interviews 8-12 weeks after the accident. Twenty-seven emotionally distressed patients and 24 minimally distressed patients were compared on the variables of psychological well-being, cognitive processing efforts, restoring a sense of meaning in life and use of coping strategies. Descriptive statistics, ANOVA and MANOVA were used to test for significant differences between the two groups. The findings showed that emotionally distressed patients scored significantly higher on efforts to cognitively process what happened, share concerns and mobilize support. They also had difficulty acknowledging the negative effects of the accident on the self and a poorer sense of psychological well-being. In contrast, minimally distressed patients evidenced a significantly greater ability to acknowledge the negative effects on the self and a higher level of psychological well-being. The potential differences between the two groups in the magnitude of the relationships of meaning, cognitive processing and coping strategies on psychological well-being were assessed by hierarchical regression equations. Psychological well-being of minimally distressed patients was characterized by a significantly higher perception of their capabilities and strengths and by an ability to acknowledge a change in their relations with family and friends.

Phases of alcohol problem prevention research

We build on precedents from other health research to present a phases model of research for alcohol problem prevention that accommodates the special characteristics of this research. We propose a five-level model, in which research moves along a series of relevant continua: from basic to more and more applied research; from descriptive hypothesis-generating pilot studies to full-fledged, methodologically sophisticated, hypothesis-testing studies; from smaller to larger samples for testing; from greater to lesser control of experimental conditions; from more artificial "laboratory" environments to real-world geographically defined communities; from testing the effects of single prevention strategies to more complex studies of multiple strategies integrated into intervention systems; and from research-driven outcome studies to "demonstration" projects that evaluate the capacity of various types of communities to implement prevention programs based on prior evaluations. The five phases of research are: (1) foundational research to define and determine the prevalence of specific alcohol-involved problems, establish causal factors and processes that yield the specific problems or increase the risk of a problem, and provide the foundations for the development of effective prevention interventions; (2) developmental (preliminary effectiveness) studies to develop and test the likely effectiveness, safety, and costs of new interventions or to assess the effectiveness, safety, and costs of an existing intervention; (3) efficacy studies to determine the effects, safety, and costs of an intervention under optimal conditions of implementation (or availability or enforcement) and acceptance (or adoption at the community, organizational, or group level; or participation, compliance, or adherence at the individual level); (4) effectiveness studies of the real-world effectiveness of preventive interventions with purposeful or natural variation in implementation and acceptance; and (5) demonstration studies of the effects of interventions when widely disseminated. The proposed phases model for alcohol problem prevention research presented herein differs in significant ways from the models established by other National Institutes of Health agencies. Greater emphasis is placed on natural experiments, on methods development along the whole research continuum, on collapsing or combining research phases when appropriate, on recognizing the critical importance of behavioral parameters early as well as late in the research sequence, and on extending the research continuum to embrace diffusion and dissemination (i.e., technology transfer) studies. We also include examples of phased research in existing alcohol studies and a discussion of relevant issues, including cost, special populations, methods, and dissemination. If systematically followed, this model has the potential to contribute to wider testing and dissemination of prevention interventions of known effectiveness.

The effects of price on the consequences of alcohol use and abuse

Economists have examined the impact of alcohol prices on various outcomes related to alcohol consumption, including nonfatal and fatal motor vehicle accidents, other accidents, liver cirrhosis, and other alcohol-related mortality, crime, and education attainment. Price, in the context of this research, includes not only the monetary price of alcoholic beverages, but also a wide variety of other "costs" of drinking and heavy drinking, including the time spent obtaining alcoholic beverages and the legal costs associated with drinking and related behavior. This research clearly demonstrates that increases in the monetary prices of alcoholic beverages, which could be achieved by increasing taxes on alcohol, can significantly reduce many of the problems associated with alcohol use and abuse. In addition, control policies that raise other "costs" of drinking, including reduced availability of alcoholic beverages, higher legal drinking ages, and others, are also effective in reducing the consequences of alcohol use and abuse.

Amiodarone causes endothelium-dependent vasodilation in human hand veins in vivo

OBJECTIVE

Amiodarone, a class III antiarrhythmic agent, is a potent coronary vasodilator. However, direct evidence for its vasodilatory effects in human vasculature in vivo is not available. The aim of the study was to investigate the short-term effects of amiodarone in preconstricted human hand veins and to explore the underlying mechanisms.

METHODS

Thirty-one healthy male volunteers were studied with the use of the dorsal hand vein compliance technique. The hand veins of the subjects were preconstricted with the alpha 1-adrenergic receptor agonist phenylephrine, and amiodarone, inhibitors of nitric oxide formation (NG-monomethyl-L-arginine, L-NMMA), and adenosine triphosphate-dependent potassium channels (glyburide [INN, glibenclamide]) were infused in the presence or absence of a cyclooxygenase inhibitor (acetylsalicylic acid), and the venodilator effect was measured. Furthermore, amiodarone was infused in prostaglandin F2 alpha (dinoprost)-preconstricted hand veins.

RESULTS

Amiodarone produced dose-dependent venodilation (51% +/- 3% maximum). Maximum amiodarone-induced venodilation was lower in dinoprost compared with phenylephrine-preconstricted veins. Pretreatment with acetylsalicylic acid reduced the amiodarone-induced venodilation by 40% +/- 6%. L-NMMA reduced the amiodarone-induced venodilation after pretreatment with acetylsalicylic acid by 72% +/- 3%. Glyburide decreased the venodilatory response of amiodarone by 31% +/- 11%, whereas only a slight but not statistically significant additional reduction in venodilation was detected after pretreatment with acetylsalicylic acid. Infusion of the solvents of commercially available amiodarone (polysorbate 80 and benzyl alcohol) did not cause vasodilation in phenylephrine-preconstricted veins.

CONCLUSIONS

Amiodarone dilates preconstricted human hand veins in vivo and acts as a venodilator through the cyclooxygenase pathway, activation of nitric oxide synthase, and blockade of alpha adrenergic mechanisms.

Invasive Trichophyton rubrum resembling blastomycosis infection in the immunocompromised host

A 55-year-old renal transplant recipient with onychomycosis and chronic tinea pedis presented with tender nodules on his left medial heel. He then developed papules and nodules on his right foot and calf. A skin biopsy demonstrated periodic acid-Schiff (PAS) positive, thick walled round cells, 2 to 6 microm in diameter, in the dermis. Skin biopsy culture grew Trichophyton rubrum. T. rubrum has been described as an invasive pathogen in immunocompromised hosts. The clinical presentation, histopathology, and early fungal culture growth suggested Blastomyces dermititidis in the differential diagnosis before the final identification of T. rubrum.

The demand for cocaine by young adults: a rational addiction approach

This paper applies the rational addiction model to the demand for cocaine by young adults in the Monitoring the Future panel. The price of cocaine is added to this survey from the Drug Enforcement Administration's System to Retrieve Information from Drug Evidence. Results suggest that annual participation and frequency of use given participation are negatively related to the price of cocaine. In addition, current participation (frequency) is positively related to past and future participation (frequency). The long-run price elasticity of total consumption (participation multiplied by frequency given participation) of -1.35 is substantial.

Lexical semantic and associative priming in Alzheimer's disease

Semantic memory impairment was investigated in patients with probable Alzheimer's disease (AD) using a threshold oral word reading task to assess priming of different lexical relationships. Healthy elderly controls showed significant priming for associatively related nouns (tempest-teapot) and also for nouns semantically related either because both designate basic-level exemplars of a common superordinate category (cousin-nephew) or because the target names the superordinate category of the prime (daughter-relative). AD patients, in contrast, showed preserved priming of lexical associates but impaired priming of certain semantic relationships. They showed no priming between words designating coordinate exemplars within a category, despite preserved priming of the superordinate category label. Findings are consistent with the view that at least part of the semantic deficit in AD is due to disruption of semantic knowledge that affects relationships among basic-level concepts, more than the relationships between these concepts and their corresponding superordinate category of membership.

Correlation of volumetric magnetization transfer imaging with clinical data in MS

We examined the relations between quantitative volumetric estimates of cerebral lesion load based on magnetization transfer imaging (MTI), clinical data, and measures of neuropsychological function in 44 patients with clinically diagnosed MS. In this population we assessed the correlation between several volumetric MTI measures, measures of neurologic function (Kurtzke Expanded Disability Status Scale and Ambulation Index), and disease duration using Spearman's correlation coefficient. Patients were classified on the basis of neuropsychological test performance as severely impaired, moderately impaired, and normal. We assessed differences between these groups with respect to MTI results using the Kruskal-Wallis test. MTI measures corrected for brain volume were found to correlate with disease duration (p < 0.01) and showed suggestive correlations with measures of neurologic impairment (p < 0.05). Individual neuropsychological tests correlated with MTI measures corrected and not corrected for brain volume (p < 0.001). An MTI measure not corrected for brain volume differed (p < 0.05) between severely impaired, moderately impaired, and normal patients. These preliminary results suggest that volumetric MTI analysis provides new measures that reflect more accurately the global lesion load in the brain of MS patients, and they may serve as a method to study the natural course of the disease and as an outcome measure to evaluate the effect of drugs.

Isolated U-fiber involvement in MS: preliminary observations

We studied the frequency and location of isolated U-fiber involvement in MS and correlated these findings exploratively with physical disability and neuropsychological impairment. Fifty-three MS patients were examined. Three-millimeter-thick, fast spin-echo T2-weighted MR images and spin-echo postgadolinium T1-weighted images were obtained. Computer software that which had been validated previously for quantitation of MS lesions was used to detect lesions on the T2-weighted images. The Expanded Disability Status Scale (EDSS), Ambulation Index (AI), and a battery of neurocognitive tests were performed on each patient. Forty-two arcuate hyperintensities along the U-fiber were detected by the software in 28 patients (53%). Twenty-seven lesions (64.3%) were seen in the frontal lobe, eight (19.0%) in the temporal lobe, three (7.1%) in the parietal lobe, three (7.1%) in the occipital lobe, and one (2.4%) in both frontal and parietal lobes. Four lesions (9.5%) showed gadolinium enhancement. Seventeen lesions (40%) were hypointense on the T1-weighted images. Scores of three of the 11 neuropsychological tests reflecting performance in executive control and memory were significantly different at least at the p = 0.05 level between the eight patients with multiple, isolated U-fiber lesions and the 45 patients without any or with only a single U-fiber lesion. No significant difference was noted for EDSS or AI. Isolated U-fiber involvement is an underappreciated MR finding in MS. Our preliminary hypothesis is that U-fiber lesions may contribute to neuropsychological impairment, although our observation requires confirmation.

Lexical semantic and associative priming in Alzheimer's disease

Semantic memory impairment was investigated in patients with probable Alzheimer's disease (AD) using a threshold oral word reading task to assess priming of different lexical relationships. Healthy elderly controls showed significant priming for associatively related nouns (tempest-teapot) and also for nouns semantically related either because both designate basic-level exemplars of a common superordinate category (cousin-nephew) or because the target names the superordinate category of the prime (daughter-relative). AD patients, in contrast, showed preserved priming of lexical associates but impaired priming of certain semantic relationships. They showed no priming between words designating coordinate exemplars within a category, despite preserved priming of the superordinate category label. Findings are consistent with the view that at least part of the semantic deficit in AD is due to disruption of semantic knowledge that affects relationships among basic-level concepts, more than the relationships between these concepts and their corresponding superordinate category of membership.

Sentence comprehension in Alzheimer's disease

We asked 22 patients with Alzheimer's disease (AD) to respond to simple probes of sentences where we manipulated grammatical factors, semantic factors, and cognitive resource demands associated with a sentence. The results demonstrated limitations in the cognitive resources needed to appreciate atypical syntactic-thematic mapping relations and difficulty processing selection restrictions associated with a verb. By comparison, comprehension in AD was not influenced by the active or passive voice of a sentence. These findings are consistent with the hypothesis that impaired sentence comprehension in AD is multifactorial in nature, including difficulty processing cognitive resource and semantic aspects of sentences.