Is Pregnancy-Related Lumbopelvic Pain Reported to Health Care Providers?

Background: Pregnancy-related lumbopelvic pain (PLPP) is a common ailment during pregnancy with physical, psychosocial, and economic consequences. Despite being common, prior literature has found that this symptom is widely underreported and therefore undertreated, especially in the United States. The objectives of this study were to determine the proportion of pregnant women who report PLPP during pregnancy to their health care providers (HCPs) and to determine what contributing factors for reporting exist. Materials and Methods: This is a cross-sectional survey design and was conducted at an academic medical center. All pregnant women attending a prenatal visit in obstetrical offices from July 2018 through March 2020 were asked to complete a questionnaire compiling demographic and socioeconomic information, answer validated survey instruments measuring physical and urinary function, and describe any pain, including intensity, frequency, and whether they told their HCPs about these symptoms and received any treatments. Results: Of the 538 respondents who had PLPP, only 43% (n = 233) reported PLPP to their provider. Of those who reported PLPP, 22% (n = 51) received treatment, of which 80% (n = 41) noted that treatment was effective. Factors that increased the likelihood of informing HCPs about PLPP were difficulty with daily mobility and a greater week of gestation. Conclusions: HCPs should inquire about PLPP throughout pregnancy. Any level of PLPP should be reported and monitored by a patient's HCP, and if it is interfering with activities of daily living, sleeping, or quality of life, it should be treated.

Lumbopelvic Pain in Pregnancy in a Diverse Urban Patient Population: Prevalence and Risk Factors

Objective: Pregnancy lumbopelvic pain (PLPP) is a common ailment during pregnancy with physical, psychosocial, and economic consequences. Prior literature has focused on majority Caucasian patient populations; none have focused on Hispanic populations, especially in the United States. The purpose of this study was to determine the proportion of pregnant people who experience PLPP in mostly Hispanic population. Materials and Methods: Cross-sectional survey Setting: Academic medical center Patients: All pregnant people attending a prenatal visit in obstetrical offices from July 2018 through March 2020 were asked to complete a questionnaire compiling demographic, socioeconomic information as well as describe any pain symptoms. Furthermore, the Pregnancy Mobility Index (PMI), Pelvic Girdle Pain Questionnaire (PGQ), and the Questionnaire for Urinary Incontinence Diagnosis (QUID) were included. Results: In a cohort (n = 851) that was 62% Hispanic, we found a 63% point-prevalence rate for PLPP. Pregnant people who reported PLPP were further along in their pregnancy, did have significantly higher scores for the PMI and PGQ, indicating a greater level of disability, and reported issues with incontinence (QUID). Results of the logistic regression found that a higher PMI score and financial instability were factors influencing PLPP. Conclusions: In a cohort of majority Hispanic people, we found that 63% of respondents had PLPP. Our study found that a higher PMI score and financial instability were factors influencing PLPP. Clinicians should be alert to pregnant people who express their difficulties with activities of daily living as they may be at risk of PLPP, and could benefit from further evaluation and treatment.

Orthographic and Phonological Facilitation from Unattended Words: Evidence for Bilateral Processing

This study investigated hemisphere differences in sensitivity to orthographic and phonological similarity using a task that did not require deliberate metalinguistic comparisons between words. Two experiments investigated the influence of an unattended distractor item on the pronunciation of target words in the right visual field (RVF) and left visual field (LVF) in neurologically intact persons. Word and pseudoword distractors that were both orthographically and phonologically similar to the target word produced equivalent facilitation across visual fields (Exp. 1). When orthographic and phonological influences were separated in Exp. 2, each dimension produced reliable facilitation, and to the same extent in each visual field. These results, and others in the literature, are difficult to reconcile with the view that the intact right hemisphere is completely unable to access phonology from print. If subsequent research confirms these findings, it would suggest that passive activation of phonology in reading can be dissociated from articulatory mechanisms, and that left hemisphere superiority in some phonological judgements may depend more on the availability of articulatory rehearsal than on privileged access to phonological codes.

Bihemispheric sensitivity to sentence anomaly

This study investigated cerebral asymmetries in sensitivity to sentence-level semantic anomaly. To separate the effects of anomalous message processing from those attributable to low sentence constraint, low-constraint sentence-fragment primes were followed by target words presented to the left or right visual fields. When completed by the target word, the sentences represented either normal or anomalous messages; in addition, one-half of the sentence primes contained a word strongly related to the target. Targets presented to both the left and right visual fields were advantaged by the presence of a related word, and disadvantaged by the presence of a semantically anomalous message. Contrary to some previous claims, this result implies that the right hemisphere can construct some message-level interpretations from sentences, such that semantic anomaly is registered, even if finer gradations of sentence constraint are not. This rudimentary integration of word meanings in sentences may provide a scaffolding for right hemisphere discourse processing. In light of these findings, we propose a revised view of left/right hemisphere differences in the processes used to interpret sentence meaning.

Does global context modulate cerebral asymmetries? A review and new evidence on word imageability effects

In this article we examine whether the distribution of function across the right and left cerebral hemispheres for lexical processing is influenced by the global context within which words are presented. A review of previously published studies indicates that the ubiquitous right visual field (RVF)/left hemisphere advantage for word recognition may be reduced or eliminated for nouns, content words, or high image words, but only when such items are presented along with verbs, function words, or low image words. However, paradoxically, when the former items are presented in more homogeneous contexts, the RVF advantage is uniformly observed. We propose that the processing efficiency of a hemisphere for a given stimulus depends on that item's relation to the other stimuli provided, that is, the global context. This was examined in a visual half-field experiment that varied whether high and low image nouns were presented in homogeneous (blocked lists) or heterogeneous (mixed lists) contexts. An unvarying RVF advantage was observed for high image words in homogeneous contexts, but this advantage was eliminated when the same items were presented in heterogeneous contexts. We suggest that stimulus heterogeneity maximizes reliance on differing, but complementary, computational biases across hemispheres. Hence, the extent to which the left and right hemispheres are recruited for the recognition of individual word types can vary dynamically with variation in the stimulus environment.

Categorical processing in the left and right hemispheres: the effect of category repetition

Previous research has indicated that the right hemisphere (RH) exhibits priming for nonassociated category members, but that the left hemisphere (LH) does not (Chiarello et al., 1990; Chiarello & Richards, 1992). Subsequent research has shown that time course is an important factor, but what other variables might influence the priming of nonassociated semantic category members? We hypothesized that repeated stimulation of the same semantic category would produce priming within the LH. Previous studies have used few exemplars from a given semantic category and thus have not tested this idea. Our prediction was that the LH would show priming after an adequate number of category instances had been processed. Based on previous research, we predicted no change in the priming observed in the RH over trial block. Priming was obtained in the RH, but it diminished as category repetition increased. In contrast, priming was not significant in the LH, indicating that category repetition does not induce maintenance of category members within the LH.

Imageability and word recognition in the left and right visual fields: a signal detection analysis

Identifying the information processing constraints that determine whether or not imagery moderates visual field asymmetries is essential for constructing a dynamic model of hemispheric interaction during language processing. In this investigation, we manipulated the global experimental context in which imageable and nonimageable words were presented by contrasting mixed and blocked word lists using a lateralized lexical decision task. Signal detection analyses were employed to assess whether global stimulus context and imageability differentially affect word discriminability (d prime) and response bias (log beta) across visual fields. Both discriminability and response bias varied with imageability and stimulus context, but to a comparable extent across visual fields. This suggests that both hemispheres are sensitive to the global context in which words are presented, and can adjust processing based not only on semantic characteristics of the words themselves, but also on the variability of items in the stimulus environment.

Distributional typicality: a new approach to estimating noun and verb usage from large scale text corpora

This paper reports a new approach to estimating the extent to which words have predominant noun and verb usages which do not require human judgments about parts of speech. The Hyperspace Analog to Language model (HAL, Lund & Burgess, 1996) was used to computationally estimate noun vs verb usage based on the statistical regularities present in a large-scale electronic text corpus. This measure can be used to estimate the extent to which a given word occurs in typical noun or verb sentence contexts (i.e., its distributional typicality) in informal contemporary discourse.

Hemispheric sensitivity to grammatical cues: evidence for bilateral processing of number agreement in noun phrases

The present experiment employed a grammatical priming task to explore the possible contributions of the left and right cerebral hemispheres to the processing of grammatical agreement. Stimuli were three-word noun phrases, with the prime centered above the fixation point and the target presented laterally to one visual field after a 600-ms stimulus onset asynchrony. Number agreement between primes and targets was varied such that the article of the prime could be consistent (i.e., each narrow shoe or all narrow shoes), inconsistent (i.e., all narrow shoe or each narrow shoes) or neutral (i.e., the narrow shoe(s)) with respect to the inflection of the target. Half of the subjects provided lexical decision responses and the other half pronunciation. The bilateral priming effect, obtained only in lexical decision, suggests that both the left and the right hemispheres are sensitive to certain grammatical cues. In addition to the task difference in priming, the inclusion of a neutral condition and of pseudo-inflected nonwords allowed these effects to be attributed to postlexical mechanisms.

Imageability and distributional typicality measures of nouns and verbs in contemporary English

Dissociations between noun and verb processing are not uncommon after brain injury; yet, precise psycholinguistic comparisons of nouns and verbs are hampered by the underrepresentation of verbs in published semantic word norms and by the absence of contemporary estimates for part-of-speech usage. We report herein imageability ratings and rating response times (RTs) for 1,197 words previously categorized as pure nouns, pure verbs, or words of balanced noun-verb usage on the basis of the Francis and Kucera (1982) norms. Nouns and verbs differed in rated imageability, and there was a stronger correspondence between imageability rating and RT for nouns than for verbs. For all word types, the image-rating-RT function implied that subjects employed an image generation process to assign ratings. We also report a new measure of noun-verb typicality that used the Hyperspace Analog to Language (HAL; Lund & Burgess, 1996) context vectors (derived from a large sample of Usenet text) to compute the mean context distance between each word and all of the pure nouns and pure verbs. For a subset of the items, the resulting HAL noun-verb difference score was compared with part-of-speech usage in a representative sample of the Usenet corpus. It is concluded that this score can be used to estimate the extent to which a given word occurs in typical noun or verb sentence contexts in informal contemporary English discourse. The item statistics given in Appendix B will enable experimenters to select representative examples of nouns and verbs or to compare typical with atypical nouns (or verbs), while holding constant or covarying rated imageability.

Sentence context and lexical ambiguity resolution by the two hemispheres

A lexical decision experiment investigated hemisphere asymmetries in resolving lexical ambiguity within a sentence context. Sentences that biased a single meaning (either dominant or subordinate) of sentence-final ambiguous words were followed by a lateralized target related to the sentence-congruent or -incongruent meaning of the ambiguous word, or an unrelated word. In the RVF sentence-congruent targets were facilitated, while incongruent targets were not primed. In contrast, related targets were facilitated in the LVF, regardless of sentence context. This suggests that selecting the contextually appropriate word meaning requires the left hemisphere, and supports a right hemisphere role in maintaining alternate word senses.

Constraints on sentence priming in the cerebral hemispheres: effects of intervening words in sentences and lists

This study explored the role of syntactic organization on semantic facilitation for target words presented to the right (R) and left (L) visual fields (VFs). Sentence and unstructured list primes were contrasted and, in each condition, the effect of intervening unrelated words on the durability of priming within each VF/hemisphere was investigated. Each prime contained a critical word which occurred Near (one intervening word) or Far (six intervening words) from the target word and was semantically related to it or a neutral control. It was hypothesized that, for word lists, facilitation for RVF target words would decrease with increasing distance between the critical and target words. For sentences no decrease in facilitation was expected for RVF targets. However, for LVF targets, facilitation was expected to decrease with distance both for sentences and lists with no greater priming for sentences than for lists. The results supported these hypotheses. Priming effects that spanned several intervening items were found only when the primes were well-structured, normal sentences and the target words were presented to the RVF. These results suggest that while word-level priming processes are available to both hemispheres, the left hemisphere makes greater use of message-level syntactic and semantic mechanisms for sentence comprehension.

Bihemispheric processing of redundant bilateral lexical information

Cerebral asymmetries in lexical ambiguity resolution were studied. In 2 experiments, targets related to the dominant and subordinate meanings of ambiguous word primes were presented for lexical decision after a 750-ms stimulus onset asynchrony. Experiment 1 compared presentation of target words to the left visual field/right-hemisphere (LVF/RH), to the right visual field/left-hemisphere (RVF/LH), or after redundant bilateral visual field (BVF) presentation. Experiment 2 examined unilateral priming in the absence of a BVF condition. On unilateral trials, priming was observed for dominant meanings in both the LVF/RH and RVF/LH, whereas subordinate priming was obtained only in the RVF/LH. These results suggest a possible role of hemispheric interaction in the availability of ambiguous word meanings. BVF performance evidenced a bilateral redundancy gain and priming that resembled that obtained on RVF/LH trials. Additional BVF analyses were not consistent with a strict race model interpretation and appear to implicate hemispheric cooperation in the bihemisperic processing of lexical information.

Bihemispheric processing of redundant bilateral lexical information

Cerebral asymmetries in lexical ambiguity resolution were studied. In 2 experiments, targets related to the dominant and subordinate meanings of ambiguous word primes were presented for lexical decision after a 750-ms stimulus onset asynchrony. Experiment 1 compared presentation of target words to the left visual field/right-hemisphere (LVF/RH), to the right visual field/left-hemisphere (RVF/LH), or after redundant bilateral visual field (BVF) presentation. Experiment 2 examined unilateral priming in the absence of a BVF condition. On unilateral trials, priming was observed for dominant meanings in both the LVF/RH and RVF/LH, whereas subordinate priming was obtained only in the RVF/LH. These results suggest a possible role of hemispheric interaction in the availability of ambiguous word meanings. BVF performance evidenced a bilateral redundancy gain and priming that resembled that obtained on RVF/LH trials. Additional BVF analyses were not consistent with a strict race model interpretation and appear to implicate hemispheric cooperation in the bihemisperic processing of lexical information.

Activation without selection: parallel right hemisphere roles in language and intentional movement?

Because language and praxis each require the activation and selection of knowledge structures in long-term memory (MacKay, 1985, 1987), it is reasonable to consider whether hemisphere asymmetries for such processes span both domains. Language and skilled movement are thought to be strongly lateralized to the left hemisphere in most individuals. Yet, although recent evidence suggests that the right hemisphere also contributes to language use in context, few similar arguments have been made for the right hemisphere's involvement in motor planning. In this paper, we review some of the evidence for a right hemisphere role in language and action processing and propose that within each domain the right hemisphere activates a range of relevant knowledge structures without selection.

Varieties of interhemispheric inhibition, or how to keep a good hemisphere down

Recent views of cerebral laterality suggest that both hemispheres contribute to the performance of most cognitive tasks. This would appear to require regulatory mechanisms to coordinate, select, and integrate the processes subserved by each hemisphere. In this paper we consider whether interhemispheric inhibition is used to achieve unified performance from a bilateral system capable of producing simultaneous and potentially conflicting, outputs. We examine the theoretical bases and empirical support offered for three varieties of interhemispheric inhibition. Interhemispheric suppression refers to mechanisms that may permit one hemisphere to halt or prevent concurrent processing by the opposite hemisphere. Such inhibition may operate either in a reciprocal, or in a unidirectional, fashion. Interhemispheric isolation may require an inhibitory process that suspends information transfer to prevent potentially harmful interhemispheric intrusions. Finally, one hemisphere could impede processing within the other via interference, that is, by providing irrelevant or detrimental information. It is argued that, while such mechanisms are plausible, evidence supportive of each is not convincing. We consider why it has been difficult to obtain clear-cut support for interhemispheric inhibition and suggest some avenues for further research.

Activation of lexical codes for simultaneously presented words: modulation by attention and pathway strength

Horizontal and vertical stings were presented in a "crosswords" format within left or right visual fields. Distractor strings were varied to examine the extent to which prelexical, orthographic-phonological, and semantic codes are activated for words not focally attended. The results supported 2 predictions of the pathway strength model of attentional modulation (JD Cohen, K Dunbar & JL McClelland, 1990). First, distractor influences were greater when participants attended to the weaker (ie, vertical) item and ignored the stronger (ie, horizontal) string, than vice versa. Second, distractors similar to the target facilitated, whereas dissimilar distractors interfered with, pronunciation responses. It is concluded that spatial attention can modulate word recognition processes, and that some interesting questions emerge when one abandons the assumptions of serial, noninteractive word recognition processes.

Depth of associated activation in the cerebral hemispheres: mediated versus direct priming

This study investigated the depth of associative activation in the cerebral hemispheres. Semantic priming was assessed for direct (WATER-DRINK) and indirect (mediated: SOAP-DRINK) associates presented to the left and right visual fields across stimulus-onset-asychronies (SOAs) of 50, 250 and 750 msec. Priming for both the direct and indirect associates was found in both visual fields at all SOAs. Our results imply that activation via associated relations in semantic memory is early and extensive in both hemispheres. We relate our findings to the previous suggestion [5, 9, 14] that meaning activation is more narrow in the left hemisphere (LH) than in the right hemisphere (RH).

Another look at categorical priming in the cerebral hemispheres

This study investigated the effect of exemplar dominance on semantic priming in the left and right visual fields for words that are members of the same category, but not strongly associated. A low proportion of related primes was employed in lexical decision and word pronunciation tasks to assess the automatic activation of word meanings in each cerebral hemisphere. Priming was reliably obtained only in the LVF/right hemisphere. In addition, this effect did not vary with category dominance of the prime:equivalent LVF priming was observed for ROBIN-CROW (high dominant) and DUCK-CROW (low dominant) pairs. These findings support the view that a broader range of related meanings is activated during word recognition in the right, than in the left, hemisphere.

Visual cerebral lateralization over phases of the menstrual cycle: a preliminary investigation

This study investigated whether visual cerebral asymmetries would change in phase with hormonal variations during the menstrual cycle. Lexical decision and line orientation tasks were administered during follicular, luteal, and menstrual phases of each woman's cycle. These tasks were also administered to a reference group of male subjects. Signal detection analyses indicated an unvarying RVF advantage in word/nonword discriminability (d') throughout the menstrual cycle, but a phase-dependent shift in left hemisphere response criterion (log beta). Gender differences were present for discriminability of line orientation, and female performance on this task varied over the cycle. The results imply that the neural systems subserving some cognitive functions are sensitive to fluctuations in gonadal steroids and suggest a hormonal basis for gender differences in some visual-spatial functions.

Adult age differences in implicit and explicit memory: time course and encoding effects

Young and older adults were tested at three delays on word-stem completion or cued recall following semantic or structural word judgments. Identical three-letter stems were present at retrieval for both implicit (completion) and explicit (cued recall) tasks; only the intention to recall list words differed. The young adults outperformed the older adults on both implicit and explicit tasks at all test delays. Under some conditions, the older but not the young adults performed more poorly on cued recall than on stem completion, suggesting a possible failure to use implicitly available information to support explicit remembering. These results suggest that some forms of implicit memory decline with normal aging.

Lateral eyes or lateralized? Hemiretinal and ocular dominance effects on visual field asymmetries for the lexical decision task

The effects of hemiretinal stimulation and ocular dominance on a visual half-field lexical decision task were investigated. Twelve right-eyed and 12 left-eyed subjects made word/nonword decisions about stimuli presented in the left and right visual field under binocular, left-eye alone, and right-eye alone viewing conditions. Both accuracy (d') and response time measures were recorded. The nasal hemiretina advantage for response time and temporal hemiretina advantage for accuracy found for face recognition (Proudfoot, 1983, Brain and Cognition, 2, 25-31) were not present when lexical decisions were made. An overall right visual field advantage was present for both eye-dominance groups. The results support a hemispheric interpretation of visual field differences for the processing of words during lexical decision.

More on words, hemifields, and hemispheres: a reply to Schwartz and Kirsner

This paper critically examines the theoretical and empirical basis for two claims made by Schwartz and Kirsner (1986, Brain and Cognition, 5, 354-361): (1) that acuity gradients can account for most visual field effects/interactions reported for horizontally presented words, and (2) the acuity gradients should be considered the "default" explanation for such findings. It is argued here that the acuity gradient account of higher order laterality effects is based on a questionable theory of lexical access, has no empirical support, and cannot explain, even in principle, many lateralization results. It is concluded that acuity gradients make little or no contribution to laterality effects when the stimuli consist of short monomorphemic words, and that theoretical explanations for such effects ought not be accepted by default.

Adult age differences in implicit and explicit memory: Time course and encoding effects

Young and older adults were tested at three delays on word-stem completion or cued recall following semantic or structural word judgments. Identical three-letter stems were present at retrieval for both implicit (completion) and explicit (cued recall) tasks; only the intention to recall list words differed. The young adults outperformed the older adults on both implicit and explicit tasks at all test delays. Under some conditions, the older but not the young adults performed more poorly on cued recall than on stem completion, suggesting a possible failure to use implicitly available information to support explicit remembering. These results suggest that some forms of implicit memory decline with normal aging.

Visual field effects for processing content and function words

This study investigated the processing of content and function words when input to the left vs right hemispheres. For both lexical decision and naming there was a larger RVF advantage for function as compared to content words: function words were processed more slowly than content in the LVF, but not in the RVF. These results do not replicate the previous report of Bradley and Garrett, Neuropsychologia 21, 155-159, 1983, and provide some support for the view that function words are less accessible to the right hemisphere. In a second experiment, there was no difference in VF asymmetry when acceptability judgments were required for function vs content word phrases. Grammaticality judgments, of any sort, may be predominantly processed in the left hemisphere.

Lexical judgments after right- or left-hemisphere injury

Patients with unilateral left- or right-hemisphere lesions were asked to make similarity judgments to visually presented words on the basis of rhyme, meaning or visual similarity. The left-hemisphere-injured group was significantly impaired, relative to controls, for all types of lexical judgments, with the greatest impairment in the rhyme condition. Patients with right-hemisphere injury were also impaired, but only when lexical judgments were based on meaning. The results are generally consistent with normal and split-brain lateralization findings, and provide evidence supportive of a right-hemisphere contribution to some aspects of lexical semantic processing.

Viewing conditions and hemisphere asymmetry for the lexical decision

Exposure duration, retinal eccentricity and stimulus size were systematically varied to assess the contribution of viewing conditions to the lexical decision asymmetry. Contrary to Sergent's hypothesis (Psychol. Bull. 93, 481-512), the RVF advantage was unaltered over the range of conditions tested. This suggests that hemisphere differences in the ability to extract information from degraded signals cannot account for the asymmetry in this task. The results are compatible with the view that the lexical decision asymmetry arises from a relatively late stage of processing in which the information is no longer represented in sensory form.

Orienting attention within visual fields: how efficient is interhemispheric transfer?

Five experiments are reported examining the effect of attentional orienting on lexical decisions within visual half-fields. In Experiment 1, following baseline performance, subjects were instructed to improve performance to the right or left of the fixation point. In Experiment 2, trials were run in blocks with all items to one side of the fixation point. In Experiment 3, completely valid position indicators as to the location of the next item to be shown were presented prior to the stimulus item. In Experiment 4, to examine practice effects, no instructions or cuing were given to subjects. In Experiment 5, subjects were urged to improve performance, but with no instructions as to location. As a summary of our results, it can be stated that (a) consistent visual field differences in lexical decision performance are present, even when subjects were informed, prior to viewing, of the spatial location of the next stimulus item. (b) Lexical decision information initially input to one cerebral hemisphere is primarily processed in that hemisphere. Interhemispheric transfer of this type of language information seems to be done primarily as the end product of a cognitive process.

The eyes have it: exposure times and saccadic movements in visual half-field experiments

Several tachistoscopic visual half-field experiments using exposure times in excess of 150 msec have been reported and arguments have been put forth justifying this procedure. An experiment was done investigating visual field accuracy under conditions where eye movement was allowed, following parafoveal exposure. Two control experiments were done to evaluate the viewing conditions. When eye movement is permitted, accuracy in both visual fields reaches 100%. It is concluded that visual field differences found with exposure times greater than 150 msec are due to the active cooperation of the subjects and not due to the justifications advanced by experimenters using long exposure times.

Automatic and controlled semantic priming: accuracy, response bias, and aging

Adult age differences in automatic and controlled semantic priming were investigated by varying the probability of valid primes in a lexical decision task. Tachistoscopic parafoveal stimulus presentation was used to assess age differences in accuracy and response bias as well as latency. Both age groups showed the expected findings of benefits without costs under automatic priming and benefits and costs under controlled priming. Errors for young adults were distributed equally among word and nonword stimuli, whereas older adults displayed a strong tendency to commit errors on nonword trials.

Orienting attention within visual fields: How efficient is interhemispheric transfer?

Five experiments are reported examining the effect of attentional orienting on lexical decisions within visual half-fields. In Experiment 1, following baseline performance, subjects were instructed to improve performance to the right or left of the fixation point. In Experiment 2, trials were run in blocks with all items to one side of the fixation point. In Experiment 3, completely valid position indicators as to the location of the next item to be shown were presented prior to the stimulus item. In Experiment 4, to examine practice effects, no instructions or cuing were given to subjects. In Experiment 5, subjects were urged to improve performance, but with no instructions as to location. As a summary of our results, it can be stated that (a) consistent visual field differences in lexical decision performance are present, even when subjects were informed, prior to viewing, of the spatial location of the next stimulus item. (b) Lexical decision information initially input to one cerebral hemisphere is primarily processed in that hemisphere. Interhemispheric transfer of this type of language information seems to be done primarily as the end product of a cognitive process.

Choosing sides: on the variability of language lateralization in normal subjects

We report test-retest reliabilities and individual asymmetries for a lateralized lexical decision task. Although acceptable reliability was found for word recognition, most subjects did not show statistically significant asymmetries, despite a robust right visual field group advantage. Inter-subject variability was unrelated to sex, handedness, or familial sinistrality. We offer some suggestions as to why these differences are to be expected in the study of normal populations.

Aphasia in a prelingually deaf woman

A left parietal infarct in a prelingually deaf person resulted in an aphasia for both American Sign Language (ASL) and written and finger-spelled English. Originally the patient had a nearly global aphasia affecting all language systems. By five to seven weeks post-onset her symptoms resembled those of hearing aphasics with posterior lesions: fluent but paraphasic signing, anomia, impaired comprehension and repetition, alexia, and agraphia with elements of neologistic jargon. In addition, there was a pronounced sequential movement copying disorder, reduced short-term verbal memory and acalculia. In general, the patient's sign errors showed a consistent disruption in the structure of ASL signs which parallels the speech errors of oral aphasic patients. We conclude that most aphasic symptoms are not modality-dependent, but rather reflect a disruption of linguistic processes common to all human languages. This case confirms the importance of the left hemisphere in the processing of sign language. Furthermore, the results indicate that the left supramarginal and angular gyri are necessary substrates for the comprehension of visual/gestural languages.