Abnormal emotional word ratings in Parkinson's disease.

Blunted facial expressions and diminished expressions of emotional prosody associated with Parkinson's disease (PD) could be attributed to motor rigidity/akinesia. Although impaired recognition of emotional faces and prosody in PD suggests emotional dysfunction is not entirely motor-efferent, comprehension might depend upon imitation with motor feedback. Thus, to learn if patients with PD have an emotional conceptual defect, we examined their ratings for the emotional connotations of words on a 1-9 scale for valence and arousal. When compared to control participants the valence (positive-negative) and arousal (excited-calm) ratings of the PD patients were blunted, but their ratings of the control expense words (expensive-cheap) were not. These blunted emotion ratings suggest that patients with PD have a degradation of their emotional conceptual-semantic system.

Timing of prenatal stressors and autism.

Recent evidence supports a role for genetics in autism, but other findings are difficult to reconcile with a purely genetic cause. Pathological changes in the cerebellum in autism are thought to correspond to an event before 30-32 weeks gestation. Our purpose was to determine whether there is an increased incidence of stressors in autism before this time period. Surveys regarding incidence and timing of prenatal stressors were distributed to specialized schools and clinics for autism and Down syndrome, and to mothers of children without neurodevelopmental diagnoses in walk-in clinics. Incidence of stressors during each 4-week block of pregnancy was recorded. Incidence of stressors in the blocks prior to and including the predicted time period (21-32 weeks gestation) in each group of surveys was compared to the other prenatal blocks. A higher incidence of prenatal stressors was found in autism at 21-32 weeks gestation, with a peak at 25-28 weeks. This does support the possibility of prenatal stressors as a potential contributor to autism, with the timing of stressors consistent with the embryological age suggested by neuroanatomical findings seen in the cerebellum in autism. Future prospective studies would be needed to confirm this finding.

Brief report: macrographia in high-functioning adults with autism spectrum disorder.

The initial description of Asperger syndrome commented on the poor handwriting and motor coordination difficulties of individuals with this condition. Early descriptions of autism do not remark upon such difficulties. Recent evidence, however, suggests that individuals with both conditions have a similar motor control impairment. Handwriting has not been formally assessed in this context. Our study compared handwriting size between individuals with autism spectrum disorder and age- and IQ-matched control subjects. Macrographia was observed among subjects with autism spectrum disorder which remained statistically significant when covaried with educational level. This finding may correlate with the anatomical abnormalities present in the cerebellum of individuals with autism spectrum disorder.

Monocular patching may worsen sensory-attentional neglect: a case report.

To determine whether monocular patching influences the performance of a patient with primarily sensory-attentional bias on the line bisection task, we present a case study of a 49-year-old woman who had right cortical infarction affecting temporal, parietal, and occipital regions. She had primarily sensory-attentional bias when performing the line bisection task on a video apparatus. In hospital, she was tested with monocular eye patching of the left or the right eye or unpatched. Paradoxically, the right-eye patching significantly worsened and the left patch significantly improved performance. The eye may have some input to the ipsilateral as well as the contralateral superior colliculus. Alternatively, the patch-a novel tactile stimulus-may induce orienting to its side via noncollicular mechanisms. When using a monocular patch for any reason, clinicians should be aware that increased spatial bias may occur.

Increased discrimination of "false memories" in autism spectrum disorder.

Individuals with autism spectrum disorder (ASD) have impaired ability to use context, which may manifest as alterations of relatedness within the semantic network. However, impairment in context use may be more difficult to detect in high-functioning adults with ASD. To test context use in this population, we examined the influence of context on memory by using the "false memory" test. In the false memory task, lists of words were presented to high-functioning subjects with ASD and matched controls. Each list consists of words highly related to an index word not on the list. Subjects are then given a recognition test. Positive responses to the index words represent false memories. We found that individuals with ASD are able to discriminate false memory items from true items significantly better than are control subjects. Memory in patients with ASD may be more accurate than in normal individuals under certain conditions. These results also suggest that semantic representations comprise a less distributed network in high-functioning adults with ASD. Furthermore, these results may be related to the unusually high memory capacities found in some individuals with ASD. Research directed at defining the range of tasks performed superiorly by high-functioning individuals with ASD will be important for optimal vocational rehabilitation.

Arousal response with aging: pupillographic study.

The performance of cognitive behaviors requires an activated, aroused cerebral cortex. Although studies have shown that there are decrements of cognitive functions in the elderly, changes in arousal with aging have not been fully studied. Our objective was to learn if there are attention-arousal changes associated with aging. Visual stimuli were presented to induce orienting responses or arousal reactions. Because changes in pupil size reflect changes in arousal, we recorded and compared pupillary responses of young and older normal participants using infared pupillography. During the 1 s that we recorded pupillary changes, we found major phases: a brief initial constriction (C1), then a maximal dilation (D1)--an arousal response, followed by constriction (C2), a habituation response. Although amplitude of these 3 phases was not different between the 2 groups, the interval between the D1 and C2 response was prolonged in the older group. Although the arousal response is not dramatically altered with aging, habituation appears to be delayed.

Noradrenergic modulation of cognitive flexibility in problem solving.

Stress causes impaired performance on tests of creativity. Drugs that block beta-adrenergic receptors improve test performance in patients with test anxiety. Furthermore, catecholamine precursors (L-DOPA) reduce the flexibility of semantic networks. Our study investigated the effect of noradrenergic system modulation on cognitive flexibility in problem solving. Eighteen normal subjects undertook three problem solving tasks (number series, shape manipulation and anagrams) 45 min after propranolol, placebo and ephedrine. On the task that appeared to rely most heavily on cognitive flexibility (anagrams), subjects who were most able to solve these problems demonstrated significantly shorter solution times (logarithmic scores) after propranolol than after ephedrine. This suggested that the noradrenergic system exerts a modulatory effect on cognitive flexibility in problem solving.

Conduction aphasia and the arcuate fasciculus: A reexamination of the Wernicke-Geschwind model.

Wernicke, and later Geschwind, posited that the critical lesion in conduction aphasia is in the dominant hemisphere's arcuate fasciculus. This white matter pathway was thought to connect the anterior language production areas with the posterior language areas that contain auditory memories of words (a phonological lexicon). Alternatively, conduction aphasia might be induced by cortical dysfunction, which impairs the phonological output lexicon. We observed an epileptic patient who, during cortical stimulation of her posterior superior temporal gyrus, demonstrated frequent phonemic paraphasias, decreased repetition of words, and yet had intact semantic knowledge, a pattern consistent with conduction aphasia. These findings suggest that cortical dysfunction alone may induce conduction aphasia.

The effect of semantic and emotional context on written recall for verbal language in high functioning adults with autism spectrum disorder.

OBJECTIVE: Several deficits have been proposed to account for cognitive impairment in autism including an inability to comprehend the perspectives of others ("theory of mind"), an inability to process emotional information, and difficulty drawing together diverse information in context ("central coherence"). Because context (central coherence) and emotion can influence memory, a study was designed to show if autism spectrum disorder was associated with impaired utilisation of context and emotion in recall; and if impairments in theory of mind processing would influence recall in autism spectrum disorder. METHODS: Ten high functioning subjects with autism spectrum disorder and 13 age and IQ matched controls were tested using recall tests. In the first coherence memory test, subjects listened to a series of word lists that were in varying degrees of syntactic and semantic (coherent) order and were asked to recall the words. In the second coherence memory test, subjects listened to stories consisting of sentences that were, or were not, in logical (coherent) order. In the emotional memory test, the subjects listened to sentences that were highly emotional or non-emotional. In the theory of mind test, the subjects listened to stories requiring varying levels of understanding of the perspectives of others. RESULTS: There were no significant differences between groups in recall of coherent versus incoherent word lists, nor was there a significant difference between groups in recall of coherent versus incoherent stories. However, the control subjects recalled more of the emotional than non-emotional sentences, whereas the autism spectrum disorder group did not show such a difference. No significant difference existed in recall of stories requiring varying levels of understanding of the perspectives of others among subjects with autism spectrum disorder, and subjects with autism spectrum disorder did not differ from control subjects in the influence of theory of mind content on story recall. CONCLUSION: The study shows that memory in high functioning adults with autism spectrum disorder is facilitated by emotional content to a lesser degree than it is facilitated by coherence. Therefore, impairments in emotional processing cannot be considered as simply an effect of the "weak central coherence" theory in autism spectrum disorder. Whereas the reasons for this emotional deficit are unknown, evidence of abnormalities of the limbic structures in autism spectrum disorder may provide an anatomical explanation.

Facilitory paratonia and frontal lobe functioning.

OBJECTIVE: To learn if paratonia predicts frontal cognitive impairments. BACKGROUND: Paratonia, an alteration of tone to passive movement, can be divided into oppositional paratonia ("gegenhalten," "paratonic rigidity") and facilitory paratonia. Although paratonia has been thought to be induced by frontal lobe dysfunction, previous studies suggest that paratonia does not correlate with cognitive impairment. However, only oppositional paratonia has been studied in this manner, and in these studies only the presence or absence of paratonia was assessed instead of a quantitative scale. Facilitory paratonia has not been studied for its relation to cognitive function. METHODS: Twenty-five patients evaluated for degenerative dementia were assessed on semiquantitative 5-point scales for paratonia by two independent raters. A quantifiable test--the modified Kral procedure--which assesses continued movement by the patient after cessation of passive movement was also administered for comparison with facilitory paratonia. To assess frontal lobe function, subjects were tested for echopraxia, distractibility, and word fluency. To screen for other cognitive defects, subjects were given the Mini-Mental State Examination (MMSE). RESULTS: The modified Kral procedure strongly correlated with subjective rating of facilitory paratonia. This correlation was significantly stronger than the correlation with oppositional paratonia. The modified Kral procedure was also highly predictive of echopraxia, but was less predictive of other frontal lobe tests. Facilitory paratonia, oppositional paratonia, and the modified Kral procedure each strongly predicted scores on the MMSE. CONCLUSIONS: Both facilitory and oppositional paratonia strongly predict general cognitive performance. The modified Kral procedure is a reliable indicator of facilitory paratonia and a predictor of impaired performance on frontal lobe tests.

Neglect after right hemisphere stroke: a smaller floodlight for distributed attention.

OBJECTIVE: To learn whether there was a defect in an attentional floodlight. We used a line decision task for which subjects had to decide if two line segments separated by a gap were one line or two parallel lines. We varied the area of the gap and, therefore, the area over which subjects needed to spread attention to perform the task correctly. BACKGROUND: Visual tasks requiring focused attention use an attentional spotlight. Other visual tasks requiring spatially distributed attention may require a floodlight. Neglect after right hemisphere stroke can be associated with a defect in the attentional spotlight. RESULTS AND CONCLUSIONS: Two patients with neglect after right hemisphere stroke performed more poorly than normal control subjects and left hemisphere-damaged control subjects as the area of spread in the gap increased. Right hemisphere-damaged patients did not differ from control subjects' performance on another visuospatial parameter--the degree of discontinuity between the line segments. These results support a defective attentional floodlight in neglect.

Progressive ventral posterior cortical degeneration presenting as alexia for music and words.

Patients with posterior cortical atrophy may have dorsal visual system (occipital-parietal) dysfunction (optic ataxia, visuospatial disorientation, and simultanagnosia), ventral visual system (occipital-temporal) dysfunction (pure alexia, prosopagnosia, visual anomia, and agnosia), or both. We report a professional musician with ventral system dysfunction whose first symptom was alexia for music. Subsequently, she developed pure alexia for words but had preserved sorting of words. These observations suggest that the ventral visual system is important in music and word reading. However, sorting of words may be mediated by the dorsal visual system.

Pure alexia: clinical-pathologic evidence for a lateralized visual language association cortex.

Traditional views of pure alexia have held that the disorder results from a disconnection between the secondary visual cortices of both hemispheres and the angular gyrus of the dominant hemisphere. Evidence has accumulated, however, suggesting the importance of the posterior inferior temporal area in visual language processing. We describe clinical-pathological support for the presence of a lateralized visual language association area residing in the dominant posterior inferior temporal lobe.

Vertical gaze paralysis and intermittent unresponsiveness in a patient with a thalamomesencephalic stroke.

A patient with paralysis of upward gaze and downward gaze, absent oculocephalic reflexes, and absent vertical saccades also demonstrated intermittent stupor over the first 9 days of presentation. Magnetic resonance imaging (MRI) demonstrated an infarct in the tegmentum of the mesencephalon including the right red nucleus and the periaqueductal area, superior to the oculomotor nucleus, and contiguous through the left thalamus. The infarct included the area around the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), as well as the midbrain reticular formation. Mechanisms are proposed for the unusual concurrent sign of intermittent unresponsiveness in this case.

Sexual activity and the morphology of steroid-sensitive rat spinal motoneurons.

In adult male rats, differential sexual experience has been shown to alter plasma androgen titers. Alterations in androgen levels have also been shown to significantly alter the structure of neurons in the spinal nucleus of the bulbocavernosus (SNB), a spinal motor nucleus that innervates perineal muscles involved in copulatory behavior. To determine if experientially induced alterations in androgen levels might alter SNB structure, male rats were assigned to one of three groups: sexually active, sexually inactive but exposed to inaccessible cycling females, and isolated. After 4 weeks of differential sexual experience, the soma size, total arbor, density, maximal fiber length, and frequency distribution of lengths of dendrites were examined in SNB motoneurons. No differences in motoneuron morphology were observed, suggesting that these motoneurons are not sensitive to socially induced alterations in androgen titers.