Paroxysmal speech disorder following left frontal brain damage

The patient was a 61-year-old female who suffered from the sudden attack of a speech disorder. The episodes of speech disorder lasted for less than 1 min, but occurred several times a day, paroxysmally. A CT revealed a low density area on the surface of the left frontal lobe and an EEG showed an abnormal wave at the frontoparietal area, more dominantly on the left. This condition was diagnosed as a kind of epilepsy. The paroxysmal speech disorder occurred very often during the 2 months after the first episode. However, with therapy using anticonvulsives and antibiotics, the condition began to improve after 4 months and disappeared completely after 6 months. It is assumed that the inflammatory change which occurred at the frontal lobe stimulated the supplementary motor area paroxysmally, and subsequently the speech disorder occurred as a kind of epilepsy.     

Information search following damage to the frontal lobes

Five adult patients with focal brain damage in different areas of the frontal lobes and five matched controls were administered a 20 Questions test. Other tests of planning, problem-solving, and decision-making were also administered to frontal lobe patients. The results indicate that damage to the frontal lobe impairs the ability to impose and utilize hierarchical organization in mental representation.     

Immoral behaviour following brain damage: A review

Despite the apparent sociability of human kind, immoral behaviour is ever present in society. The term ‘immoral behaviour’ represents a complex array of conduct, ranging from insensitivity to topics of conversation through to violent assault and murder. To better understand the neuroscience of immoral behaviour, this review investigates two clinical populations that commonly present with changes in moral behaviour – behavioural-variant frontotemporal dementia and acquired brain injuries. Based on evidence from these groups, it is argued that rather than a single underlying cause, immoral behaviour can result from three distinct types of cognitive failure: (1) problems understanding others; (2) difficulties controlling behaviour; or (3) deficits in the capacity to make appropriate emotional contributions. Each of these failures is associated with damage to different brain regions. A more nuanced approach to the neuroscience of immoral behaviour has important implications for our understanding of immoral behaviour in a wide range of clinical groups, as well as human society more broadly.     

Recovery of susceptibility following audiogenic seizure in mice.

The rate at which SJL/J mice recover susceptibility following an initial sound-induced seizure was examined. Fewer than 15% of the subjects seized when retested after a 2-min delay, and only 50% reseized after a 10-min delay. The likelihood of a second seizure was enhanced if the initial seizure exhibited a rapid progression to clonus. During the retest, seizures progressed more slowly than during the initial test, which indicates that recovery was not complete even if a second seizure was induced. Finally, recovery of seizure susceptibility was prevented as long as the subject continued to be exposed to intense auditory stimulation following the initial convulsion, an effect previously noted by Alexander and Kopeloff (1980). The findings are discussed in terms of a recently proposed central inhibitory model of the recovery of audiogenic seizure susceptibility.     

Failure to acquire an inhibitory task following seizure-induced brain damage

Male rats that had displayed limbic seizures following a single pair of systemic injections of lithium and pilocarpine were trained 2 months later on an operant schedule that required differential low rates of responding (DRL). The seizured rats never acquired schedules that required either 6-sec. or 12-sec. inhibition of responses following a reward; these rats displayed more perseverative responding and shorter interresponse times than controls. Histomorphology indicated severe brain damage primarily within the entorhinal cortices (and adjacent amygdala) and dorsal thalamus.     

Alcohol-induced changes in contrast sensitivity following high-intensity light exposure

Relatively low doses of alcohol produced large, significant, dose-related increases in the time required to recover foveal contrast sensitivity following bright light exposure. Nine subjects participated in a double-blind experiment involving three dose levels of alcohol (including placebo). The luminance parameters of the test were comparable to those encountered in practical situations such as driving. The alcohol-induced delay in glare recovery is probably retinal and lasts for several hours after drinking.     

Functional recovery following brain damage: conceptual frameworks and biological mechanisms

Mammals are well known to manifest recovery over time of many functional impairments induced by brain lesions. A brief reveiw is provided of the different conceptual frameworks within which functional recovery has been examined in the literature, and of different neurobiological mechanisms that have been proposed to account for the phenomenon. We observe that these two levels of analysis have frequently been only loosely related. Finally, a newly identified biological mechanism—compensatory collateral sprouting—is described which appears to be closely related to functional recovery in animals with hippocampal lesions, and this is proposed as a powerful new model within which to investigate further the relationship between the phenomenon of functional recovery and its underlying mechanisms.     

An investigation of the ability to process inferences in language following right hemisphere brain damage

Twenty-two right hemisphere brain-damaged and 22 non-brain-damaged patients were given a multiple-choice recognition task which contained true statements, statements which were inferentially true but not actually heard before, and false statements. It was hypothesized that if right hemisphere brain damage disturbs the ability to comprehend inferences, these subjects, unlike their normal counterparts, would not falsely recognize true inferences as heard before. This hypothesis was not confirmed. However, the right hemisphere group was poorer than controls at rejecting false statements. This behavior was speculated to be a retrieval difficulty, which was exacerbated if the information contained spatial or semantically similar material.     

Developmental changes in the recognition and comprehension of facial expression: implications for frontal lobe function.

Children aged 6-15 years old and adults (over 18) were given three tests designed to test perception and comprehension of facial expression. In the first test subjects were given two composite symmetrical faces made from the left or right half of a normal face, the subjects' task being to indicate which composite more closely resembled the original face. In the second test the subjects matched a series of photographs from Life magazine with key photographs of one of six distinct emotions (sad, fear, happy, anger, disgust, surprise). In the third test the subjects chose a key photograph that was appropriate for the face of a faceless character in a cartoon. On the composite faces test the subjects in all groups exhibited a preference for the left visual field composite, implying that all age groups were processing the faces in a similar manner. The results of the other two tests showed that there was an improvement in the perception of facial expression between the ages of 6 and 8 years, little change until about 13 years, and then a second improvement to adult performance at about 14 years. The performance of the 8- to 13-year-old children was similar to that of adult patients with frontal lobe injuries, which could be taken as evidence that the regions of the frontal lobe involved in the performance of these tasks may not be mature until about 14 years of age.     

Movement in the ipsilesional hand is segmented following unilateral brain damage

Unilateral stroke results in hemiplegia or hemiparesis of the contralateral side of the body. The ipsilateral side of the body, the so-called "good" side, is often assumed to have no deficit. However, there is increasing evidence that the function of the unaffected limbs, especially the upper extremities, is different from that of normal age-matched controls. In the present study, we examined the motor control of both hands of chronic stroke subjects, 6 with left hemisphere brain damage (LHBD) and 5 with right hemisphere brain damage (RHBD). The control group consisted of 5 normal age-matched subjects. The task of the subject was to move a handle by flexing his/her fingers until the target position was reached. The target position was set as 33% of the range of each subject. No time constraints were imposed. The movements of the normal subjects were basically smooth, with few hesitations. In contrast to this, the movements of both hands in the two stroke groups were segmented and characterized by multiple starts and stops. As compared to normals, the time to reach the target, the number of pauses during the movement, and the percent of time spent in pauses, were significantly greater for both hands of the LHBD group. In the RHBD group, the percent of time spent in pauses was significantly greater than the control group for the ipsilesional hand. The increased segmentation seen in the movements of the ipsilesional, as well as the contralesional. hands of the hemiplegic subjects suggests that the motor deficits in stroke patients may be due to a global inability to correctly plan and carry out movements.     

Emotional processing following cortical and subcortical brain damage: contribution of the fronto-striatal circuitry

The present study examined the differential contribution of cortical and subcortical brain structures in emotional processing by comparing patients with focal cortical lesions (n = 32) to those with primarily subcortical dysregulation of the basal ganglia (Parkinson's disease n = 14). A standardized measure of emotional perception (Tübingen Affect Battery) was used. Only patients in the more advanced stages of Parkinson's disease and patients with focal damage to the (right) frontal lobe differed significantly from controls in both facial expression and affective prosody recognition. The findings imply involvement of the fronto-striatal circuitry in emotional processing.     

Developmental changes in sensitivity to vocal paralanguage

Developmental changes in children’s sensitivity to the role of acoustic variation in the speech stream in conveying speaker affect (vocal paralanguage) were examined. Four‐, 7‐ and 10‐year‐olds heard utterances in three formats: low‐pass filtered, reiterant, and normal speech. The availability of lexical and paralinguistic information varied across these three formats in a way that required children to base their judgments of speaker affect on different configurations of cues in each format. Across ages, the best performance was obtained when a rich array of acoustic cues was present and when there was no competing lexical information. Four‐year‐olds performed at chance when judgments had to be based solely on speech prosody in the filtered format and they were unable to selectively attend to paralanguage when discrepant lexical cues were present in normal speech. Seven‐year‐olds were significantly more sensitive to the paralinguistic role of speech prosody in filtered speech than were 4‐year‐olds and there was a trend toward greater attention to paralanguage when lexical and paralinguistic cues were inconsistent in normal speech. An integration of the ability to utilize prosodic cues to speaker affect with attention to paralanguage in cases of lexical/paralinguistic discrepancy was observed for 10‐year‐olds. The results are discussed in terms of the development of a perceptual bias emerging out of selective attention to language.     

Planning and problem solving skills following focal frontal brain lesions in childhood: analysis using the Tower of London.

Problem solving skills were investigated in children with focal lesions using the Tower of London test (TOL; Shallice, 1982). The scoring procedure was elaborated from previous studies to delineate separate processes contributing to overall performance in children. Thirty-one children with focal frontal pathology, 18 children with focal pathology in other brain regions (extra-frontal), 17 children with generalized pathology and 38 healthy children participated in the study. Results suggest a distributed network for problem solving skills, particularly cognitive flexibility and goal setting skills. Within the frontal group, children with lesions involving the right pre-frontal cortex had greatest problems with self-regulation, with rule breaks most common among this group. As these skills develop relatively early in comparison to other aspects of executive function, right pre-frontal regions may play a particularly important role in the development of executive skills in childhood, with damage to these regions rendering children vulnerable to a range of cognitive and social deficits.     

Processing homonymy and polysemy: effects of sentential context and time-course following unilateral brain damage

The present study investigated the abilities of left-hemisphere-damaged (LHD) non-fluent aphasic, right-hemisphere-damaged (RHD), and normal control individuals to access, in sentential biasing contexts, the multiple meanings of three types of ambiguous words, namely homonyms (e.g., "punch"), metonymies (e.g., "rabbit"), and metaphors (e.g., "star"). Furthermore, the predictions of the "suppression deficit" and "coarse semantic coding" hypotheses, which have been proposed to account for RH language function/dysfunction, were tested. Using an auditory semantic priming paradigm, ambiguous words were incorporated in dominant- or subordinate-biasing sentence-primes followed after a short (100 ms) or long (1,000 ms) interstimulus interval (ISI) by dominant-meaning-related, subordinate-meaning-related or unrelated target words. For all three types of ambiguous words, both the effects of context and ISI were obvious in the performance of normal control subjects, who showed multiple meaning activation at the short ISI, but eventually, at the long ISI, contextually appropriate meaning selection. Largely similar performance was exhibited by the LHD non-fluent aphasic patients as well. In contrast, RHD patients showed limited effects of context, and no effects of the time-course of processing. In addition, although homonymous and metonymous words showed similar patterns of activation (i.e., both meanings were activated at both ISIs), RHD patients had difficulties activating the subordinate meanings of metaphors, suggesting a selective problem with figurative meanings. Although the present findings do not provide strong support for either the "coarse semantic coding" or the "suppression deficit" hypotheses, they are viewed as being more consistent with the latter, according to which RH damage leads to deficits suppressing alternative meanings of ambiguous words that become incompatible with the context.     

Recovery and predictors of language skills two years following pediatric traumatic brain injury

Subtle language processing difficulties may adversely affect scholastic performance, as well as communication and social skills. It is therefore crucial that language skills are monitored following traumatic brain injury (TBI) in childhood. The present study examined language skills in a group of 68 children who had sustained a mild, moderate or severe TBI. Results indicated that during the acute stage a dose-response relationship was evident, where severe TBI was associated with poorest performance and mild TBI with least deficits. By 24 months post-TBI, it was clear that for some language functions, the severe TBI group showed substantial recovery, and at times performed better than the moderate TBI group. Predictors of language and literacy skills at 24 months post TBI included pre-injury communication skills, socio-economic status, age at injury, and Vocabulary, as measured by the Wechsler Intelligence Scale for Children (WISC-111).