Frontal Brain Damage Research Articles

Confabulations in a teenager with a right frontal hemispherotomy: Possible underlying mechanisms

Objective: Confabulations, i.e. false memories without intention to deceive, can be observed in adults with frontal brain damage. Confabulations are typically associated with episodic memory and/or executive disorders although the severity of these impairments is highly variable. Confabulations may also be associated with emotional/motivational particularities, as a positive bias seems to prevail in such situations. Several distinct cognitive and socio-affective processes may account for the various types of confabulations and these issues remain open. Method: We present the case of a teenager with an early acquired frontal damage, referred for “strange lies.” Besides a standard neuropsychological assessment, we explored (1) source memory, using a reality-monitoring task, (2) episodic autobiographical memory, including both the recollection of the past memories and the ability to imagine future personal events, with an episodic future thinking task (EFT), (3) the sense of self, with questionnaires targeting self-representations, self-esteem and self-competence. Results: The results showed the expected source memory deficits and poor episodic future thinking, whereas episodic autobiographical memory was preserved, contrary to the episodic memory dysfunction usually evidenced in adult confabulators. The confabulations produced by this teenager displayed a clear positive bias, seemed to fit to personal/social goals and to wishful ideations, and were associated with an above average self-esteem and self-representation. Conclusions: These results support the hypothesis of self-identity and emotional regulatory roles of the confabulations. Although the literature on confabulating children/teenagers is nearly non-existent, a more systematic screening of confabulations should be conducted in order to avoid false interpretation to strange discourse or behavior.

Dr. Strangelove demystified: Disconnection of hand and language dominance explains alien-hand syndrome after corpus callosotomy

BackgroundAlien hand syndrome (AHS) is a disabling condition in which one hand behaves in a way that the person finds "alien". This feeling of alienation is related to the occurrence of movements of the respective hand performed without or against conscious intention. Most information on AHS stems from single case observations in patients with frontal, callosal, or parietal brain damage. MethodsRetrospective analysis of distinctive clinical features of three out of 18 epilepsy patients who developed AHS with antagonistic movements of the left hand after corpus callosotomy (CC) (one anterior, two complete) for the control of epileptic seizures, particularly epileptic drop attacks (EDA). ResultsRemarkably, these three patients, two men and one woman, displayed atypical language dominance with a bilateral, left more than right hemisphere language representation in intracarotidal amobarbital testing before surgery. The overall additional distinctive feature of the target patients was genuine left-handedness, with writing retrained to right-handedness in two patients. After surgery the left hands became alien. The problem was permanent, despite strategies for compensation. ConclusionFrom this observation we suggest that under the conditions of dissociation of language and motor dominance, loss of both intentional control of contralateral action and physiological inhibition of antagonistic movements lead to post-callosotomy alien-hand-like motor phenomena. The dissociation pattern posing this risk seems rare but needs to be considered when evaluating candidates for callosotomy.

Empathy and schizotypy following acquired brain damage.

Acquired brain damage is associated with a reduced capacity for empathy, and emerging evidence indicates that there may also be elevated levels of schizotypy. However, although a relationship between schizotypy and empathy has been identified in other populations, no study to date has tested whether this relationship is also evident following acquired brain damage, and if so, whether it is specific to certain types of brain damage, or specific types of empathy. People with acquired brain damage restricted to either frontal (N=18) or non-frontal (N=24) neural structures and demographically matched controls (N=48) completed an assessment of schizotypy and a measure of empathy that differentiated between cognitive, emotional, and social skills empathy. Relative to the control group, people with frontal and non-frontal brain injuries reported elevated schizotypy, with the frontal group also reporting lower social skills empathy. Only in the frontal group was there support for an association between schizotypy and empathy, and this was specific to the social skills component of empathy. Schizotypy levels are elevated following brain damage, and frontal brain injury is linked to greater difficulties with the social skills component of empathy. Schizotypy appears to be an important consideration when understanding the link between empathy and frontal brain damage, with higher schizotypy levels associated with reduced social skills empathy in this population. Future research is now needed to establish whether problems with more implicit aspects of social understanding are relevant to understanding the relationship between schizotypy and poor social behavioural outcomes identified in other clinical groups that present with frontal brain damage. People with an acquired brain injury experience deficits in empathic processing as well as elevated levels of schizotypal traits. Schizotypy levels and social skills empathy were inversely related in people who had experienced a frontal acquired brain injury, suggesting that schizotypy might be important for understanding social skill difficulties in this particular population. These findings highlight the potential benefit of including social cognitive assessments and schizotypy measures in standard neuropsychological assessment batteries.

Effects of sulforaphane on cognitive function in patients with frontal brain damage: study protocol for a randomised controlled trial

IntroductionMany patients with frontal brain damage show serious cognitive function deficits, which hamper their quality of life and result in poor clinical outcomes. Preclinical research has shown that sulforaphane can...

Effects of Sulforaphane on Cognitive Function in Patients With Frontal Brain Damage

Effects of Sulforaphane on Cognitive Function in Patients With Frontal Brain Damage

Unilateral parietal brain injury increases risk-taking on a rat gambling task

Traumatic brain injury (TBI) affects millions of individuals every year. Many of these injuries lead to lasting effects, particularly impairments in domains broadly classified as executive functions, such as impulse control and decision-making. While these impairments have been historically associated with frontal brain damage, other injuries such as concussion or parietal injury also contribute to similar dysfunction. However, it is unknown whether animal models of TBI would replicate these broad effects that are observed in human patients. In the current study, we delivered a unilateral parietal controlled cortical impact injury and assessed the performance of rats on a motoric task (rotarod) and a test of decision-making and impulsivity (rodent gambling task). TBI rats demonstrated significant motor impairments on the rotarod task; however, this did not extend to difficulties inhibiting motor actions (impulsivity). In addition, TBI caused chronic alterations to risk-based decision-making, extending out to 12 weeks post-injury. Specifically, rats with TBI preferred the riskiest, and most suboptimal option over all others. The current data suggest that models of unilateral TBI are sufficient for replicating some aspects of executive dysfunction (risky decision-making), while others are limited to frontal damage (impulsivity). These models may be used to develop therapeutics targeted at the chronic post-injury period when these symptoms often manifest in patients, a critically understudied area in preclinical TBI research.

Personally salient, emotionally negative task contexts provoke goal neglect in depression.

Goal neglect refers to a dissociation between intended and actual action. Although commonly associated with frontal brain damage, this phenomenon is also characteristic of clinical depression. To date, tests of goal neglect typically require individuals to switch between subtasks populated with neutral stimuli. This study examined the impact of affective and personally salient stimulus contexts on goal neglect in clinical depression. Participants were randomly allocated to either positively or negatively-valenced versions of the Affective Six Elements Test (A-SET). We hypothesised that depressed individuals (n = 30) would exhibit an overall impairment in A-SET performance by neglecting entire subtasks and allocating suboptimal time to each task, relative to never-depressed peers (n = 30), with effects being strongest for the negatively-valenced version. Findings showed that depressed individuals exhibited specific deficits, relative to controls on these measures in the negative A-SET only, with a magnitude comparable to that found in brain injured patients. Individuals with depression are impaired in their ability to monitor performance and implement strategies that are optimal for the purpose of pursuing an overarching goal when the task context is negatively-valenced. Potential mechanisms are discussed.

Impact of Prefrontal Theta Burst Stimulation on Clinical Neuropsychological Tasks.

Theta burst stimulation (TBS) protocols hold high promise in neuropsychological rehabilitation. Nevertheless, their ability to either decrease (continuous, cTBS) or increase (intermittent, iTBS) cortical excitability in areas other than the primary motor cortex, and their consistency modulating human behaviors with clinically relevant tasks remain to be fully established. The behavioral effects of TBS over the dorsolateral prefrontal cortex (dlPFC) are particularly interesting given its involvement in working memory (WM) and executive functions (EF), often impaired following frontal brain damage. We aimed to explore the ability of cTBS and iTBS to modulate WM and EF in healthy individuals, assessed with clinical neuropsychological tests (Digits Backward, 3-back task, Stroop Test, and Tower of Hanoi). To this end, 36 participants were assessed using the four tests 1 week prior to stimulation and immediately following a single session of either cTBS, iTBS, or sham TBS, delivered to the left dlPFC. No significant differences were found across stimulation conditions in any of the clinical tasks. Nonetheless, in some of them, active stimulation induced significant pre/post performance modulations, which were not found for the sham condition. More specifically, sham stimulation yielded improvements in the 3-back task and the Color, Color-Word, and Interference Score of the Stroop Test, an effect likely caused by task practice. Both, iTBS and cTBS, produced improvements in Digits Backward and impairments in 3-back task accuracy. Moreover, iTBS increased Interference Score in the Stroop Test in spite of the improved word reading and impaired color naming, whereas cTBS decreased the time required to complete the Tower of Hanoi. Differing from TBS outcomes reported for cortico-spinal measures on the primary motor cortex, our analyses did not reveal any of the expected performance differences across stimulation protocols. However, if one considers independently pre/post differences for each individual outcome measure and task, either one or both of the active protocols appeared to modulate WM and EF. We critically discuss the value, potential explanations, and some plausible interpretations for this set of subtle impacts of left dlPFC TBS in humans.

Frontal lobe brain damage and the lived piano-playing experiences of an older adult

ABSTRACTThis paper presents an interpretative phenomenological analysis (IPA) of the lived piano-playing experiences of an older adult who suffered frontal lobe brain damage. Semi-structured interviews and diary reflections were used to gain insight into the intrapersonal, relational, spiritual and therapeutic experiences of the participant, Annie. Emergent themes include being ill, loss, depression and anxiety, determination, yearning, will to live and spirituality. Annie’s experiences are discussed against the background of the additional impact of a frontal lobe brain injury on cognition, memory, ability to learn a new skill and personality. Furthermore, her experiences are also discussed in the light of logotherapeutic principles. The role of music and specifically of piano playing in general wellbeing and rehabilitation after brain injury is highlighted.

Olfactory Function in Head Trauma Patients a Link to Frontal Brain Damage?

Aims: In the recent years, the olfactory system gained more attention because of its unique characteristics of continuous regeneration and neurogenesis in adults. This is necessary for maintaining an intact olfactory function throughout life. Nevertheless, several diseases with olfactory dysfunction have been identified. Especially head trauma has shown to be linked to olfactory impairment. This is of interest because it is believed that measurement of olfactory function after head trauma represents a sensitive tool for measuring frontal brain damage. Most of the studies regarding this topic were conducted in adults. The aim of this study, therefore, is to evaluate the effect of mild head trauma in children on olfactory function over a time period of up to 1 year after head trauma.

Olfactory Function After Mild Head Injury in Children

Olfactory impairment has been shown to be linked to head injury. In addition, it is believed that measurement of olfactory function after head trauma represents a sensitive tool for measuring frontal brain damage. Aim of the study was to evaluate the effect of mild head trauma in children on olfactory function over a time period of up to 1 year after head trauma. The olfactory function of 114 children who suffered mild head trauma according to the Glasgow Coma Scale was assessed 3 times with an interval of 4 months. In addition, healthy, age-matched controls were tested for comparison of olfactory function. Patients scored significantly lower on the odor threshold test compared to the control group-but still within normal range. Between the 2 groups, no difference was found for suprathreshold testing. Neither olfactory threshold scores nor olfactory discrimination scores changed significantly over the study period of 1 year. This data prove an impact of mild head trauma on olfactory function of children. It seems unlikely that children who suffered mild head trauma will become hyposmic or anosmic.

Simple tone discriminations are disrupted following experimental frontal traumatic brain injury in rats

Primary objective: To assess cognitive deficits in a rat model of brain injury.Research design: Cognitive deficits are some of the most pervasive and enduring symptoms of frontal traumatic brain injury (TBI) in human patients. In animal models, the assessment of cognitive deficits from TBI has primarily been limited to tests of spatial learning. Recently, simple discrimination performance has been shown to be sensitive to frontal brain damage. The current study provides a detailed characterization of deficits in a two-choice tone discrimination following a bilateral frontal controlled cortical impact injury.Methods and procedures: Rats were trained on a two-tone discrimination task in a standard operant chamber, then either a frontal brain injury was delivered or sham procedures performed. Following recovery, they were re-tested on the discrimination task and then tested on a reversal of the discrimination.Main outcomes and results: Frontal injury caused substantial deficits in responding and discrimination accuracy as well as an increase in side bias.Conclusions: Based on the outcomes seen in this study, discrimination and other operant tasks may provide a sensitive tool to assess the effect of therapeutic agents on cognitive deficits in animal models, which could lead to improved characterization of deficits and yield an improved assessment tool to aid in drug discovery.

Homonymous hemianopia and related visual defects: Restoration of vision after a stroke.

The term homonymous hemianopia refers to visual impairment due to a post-chiasmatic brain lesion. Mammalian neurons of the central nervous system do not have the ability to regenerate. However, the cerebral cortex shows plasticity in certain cases. Motor or speech disorders due to frontal lobe brain damage can be improved with well-directed rehabilitation techniques. If such plasticity is possible, it raises the question whether specialized training could improve a cortical visual disorder. There is need for simple visual training which could be used in rehabilitation. A few different approaches have been developed to treat patients with hemianopia: (1) substitution including special devices, such as optical prisms; (2) compensation using intact residual abilities - especially training of eye movements; (3) restitution which is based on stimulating the blind hemifield. The third method of rehabilitation is the most controversial; however, it has the largest potential. To support concepts of the targeted rehabilitation outlined here, first: further development of the theory of plasticity in visual pathways is required and second: the efficacy of the rehabilitation procedures has to be demonstrated by clinical evidence. We review methods and approaches of hemianopia rehabilitation and treatment. We also review results of contemporary clinical studies and meta-studies.

The Dig Task: A Simple Scent Discrimination Reveals Deficits Following Frontal Brain Damage

Cognitive impairment is the most frequent cause of disability in humans following brain damage, yet the behavioral tasks used to assess cognition in rodent models of brain injury is lacking. Borrowing from the operant literature our laboratory utilized a basic scent discrimination paradigm1-4 in order to assess deficits in frontally-injured rats. Previously we have briefly described the Dig task and demonstrated that rats with frontal brain damage show severe deficits across multiple tests within the task5. Here we present a more detailed protocol for this task. Rats are placed into a chamber and allowed to discriminate between two scented sands, one of which contains a reinforcer. The trial ends after the rat either correctly discriminates (defined as digging in the correct scented sand), incorrectly discriminates, or 30 sec elapses. Rats that correctly discriminate are allowed to recover and consume the reinforcer. Rats that discriminate incorrectly are immediately removed from the chamber. This can continue through a variety of reversals and novel scents. The primary analysis is the accuracy for each scent pairing (cumulative proportion correct for each scent). The general findings from the Dig task suggest that it is a simple experimental preparation that can assess deficits in rats with bilateral frontal cortical damage compared to rats with unilateral parietal damage. The Dig task can also be easily incorporated into an existing cognitive test battery. The use of more tasks such as this one can lead to more accurate testing of frontal function following injury, which may lead to therapeutic options for treatment. All animal use was conducted in accordance with protocols approved by the Institutional Animal Care and Use Committee.

The Dig Task: A Simple Scent Discrimination Reveals Deficits Following Frontal Brain Damage

Cognitive impairment is the most frequent cause of disability in humans following brain damage, yet the behavioral tasks used to assess cognition in rodent models of brain injury is lacking. Borrowing from the operant literature our laboratory utilized a basic scent discrimination paradigm1-4in order to assess deficits in frontally-injured rats. Previously we have briefly described the Dig task and demonstrated that rats with frontal brain damage show severe deficits across multiple tests within the task5. Here we present a more detailed protocol for this task. Rats are placed into a chamber and allowed to discriminate between two scented sands, one of which contains a reinforcer. The trial ends after the rat either correctly discriminates (defined as digging in the correct scented sand), incorrectly discriminates, or 30 sec elapses. Rats that correctly discriminate are allowed to recover and consume the reinforcer. Rats that discriminate incorrectly are immediately removed from the chamber. This can continue through a variety of reversals and novel scents. The primary analysis is the accuracy for each scent pairing (cumulative proportion correct for each scent). The general findings from the Dig task suggest that it is a simple experimental preparation that can assess deficits in rats with bilateral frontal cortical damage compared to rats with unilateral parietal damage. The Dig task can also be easily incorporated into an existing cognitive test battery. The use of more tasks such as this one can lead to more accurate testing of frontal function following injury, which may lead to therapeutic options for treatment. All animal use was conducted in accordance with protocols approved by the Institutional Animal Care and Use Committee.

遂行機能障害に対する認知リハビリテーション

遂行機能障害とは，前頭前野の障害により，後部脳における認知機能は保たれているものの，それらを動員して課題の解決にあたることが困難な病態であると理解される。それによりプランニングの障害，戦略の適用ができない，自己制御の障害，抑制が利かない，ゴール志向的行動が困難，行動の開始が困難，さらに自己洞察ができない，という一連の行動の障害が生じる。認知リハビリテーションの理論的枠組みとして，Normann と Shallice による情報処理モデルにより，不適切なスキーマを抑制し最適なスキーマが選択される思考・行動スキーマの変更の手法が支持されている。さらに Cicerone によるsystematic review では問題解決訓練が推奨されており，同様にゴールマネジメント訓練の有用性が支持されている。

Passage of an iron bar through the head: 50-year follow-up

Most neurologists are familiar with the case of Phineas Gage and the consequences of the passage of an iron bar through his head in an accident sustained in 1848. The case may be said to be the one of the beginnings of cognitive neuropsychology [1, 2, 4, 6, 7]. However, only occasional cases of passage of an iron bar through the head with longterm follow-up have been published since Gage [3, 8]. We present the clinical and cognitive findings in a patient over 50 years after an accident in which an iron bar passed through his head. In 1954, at the age of eight, the patient and his friends were playing with iron rods found in a building yard, throwing them as spears. One throw accidentally pierced the patient’s head, passing from the right occipital to the right frontal region: he recalled a piece of brain sticking out on the iron rod in front of his eyes. Following surgical removal of the bar, and a second operation to re-explore the wound, the ‘‘miracle boy’’ (as described in the local press) went on to make an excellent recovery, although he was left with mild weakness and involuntary movements of the left (non-dominant) arm, because of which he attended a special school. However, subsequent social and occupational function was not impaired: he raised a family, learned to drive, and worked in paid employment for a public utility company for many years. Assessed at age 64, some 56 years after his injury, he was able to give a full account of the accident and of his subsequent life. On neurological examination, he had a mild left spastic hemiparesis with some dystonia in the arm. Assessing his cognitive function, his score on the Mini-Mental State Examination was 30/30 and on the Frontal Assessment Battery 15/18 (impaired inhibitory control and motor series). On the Mini-Mental Parkinson [5] he scored 29/32, losing three points for the visual registration test. On neuropsychological assessment Wechsler Adult Intelligence Scale III (WAIS III) showed intellectual function in the average range (full scale IQ 98) with no evidence of intellectual decline (Wechsler Test of Adult Reading predicted full scale IQ 97). Wechsler Adult Intelligence Scale III performance on tests of processing speed was borderline (fifth percentile). On the Wechsler Memory Scale (WMS III) he was borderline on both immediate and delayed memory. Language function was preserved on the Graded Naming Test. Copy of the Rey figure showed difficulties in planning and was slow (both copy and time Bfirst percentile). On the Delis–Kaplan Executive Function System he was impaired on measures of cognitive flexibility, abstract thinking and category formation. Brain imaging (CT) confirmed right occipital and frontal brain damage. Unlike Phineas Gage, our patient suffered no dramatic change in personality following his brain injury, and maintained normal social and occupational function throughout his adult life. On neuropsychological assessment he did show mild cognitive impairments, in processing speed, short-term memory and learning for verbal and visual material, visual spatial planning, and in some aspects of executive functions. Gage’s physician, Dr. Harlow, following his patient up in 1868, some 20 years after the accident, argued that the frontal lobe lesion had caused a loss of planning skills. The neurobehavioral changes, sometimes labelled B. M. Aji E. J. Ghadiali A. Jacob A. J. Larner (&) Cognitive Function Clinic, Walton Centre for Neurology and Neurosurgery, Lower Lane Fazakerley, Liverpool L9 7LJ, UK e-mail: a.larner@thewaltoncentre.nhs.uk

Left Dorsomedial Frontal Brain Damage Is Associated with Insomnia

Insomnia is a common sleep disorder, yet its pathophysiological basis remains poorly understood. Studying a group of 192 patients with focal brain lesions, we show a significant association between insomnia and left dorsomedial prefrontal damage. Our findings are the first to demonstrate a link between insomnia and a discrete locus of brain damage, providing novel insight into the neurobiological mechanisms of sleep maintenance.

Nonfluent aphasia and the evolution of proto-language

This paper briefly explores the relevance of patterns of related symptoms of nonfluent aphasia arising from left inferior frontal brain damage for the evolution of speech, language and gesture. I discuss aphasic lexical speech automatisms (LSAs) and their resolution with recovery into agrammatism with apraxia of speech and draw parallels between this recovery and the early evolution of language to protospeech and protosyntax. I focus attention on the most common forms of LSAs, expletives and the pronoun + modal/aux subtype, and propose that further research into these phenomena can contribute to the debate on the evolution of speech and language.

Memory and executive impairment in schizophrenia: comparison with frontal and temporal brain damage

Although poor neuropsychological test performance is well documented in schizophrenia, how closely it resembles that seen in patients with brain damage in terms of cognitive failures in daily life and stability over time has been little studied. Thirty patients with chronic schizophrenia, 24 patients with frontal or temporal brain damage and 30 healthy controls were given a battery of memory and executive tests. Carers of the two patient groups also completed questionnaires rating memory and executive failures in daily life. Testing was repeated 6 weeks later. The schizophrenia and the brain-damaged patients were significantly impaired on most, but not all tests. The degree of carer-rated memory or executive failure was similar in the two groups, but the schizophrenia patients were rated as having significantly more executive failures than memory failures, whereas the brain-damaged patients showed the reverse pattern. Both groups of patients showed similar consistency of performance across sessions. Neuropsychological impairment in schizophrenia resembles that seen in patients with brain damage, not only in terms of overall severity, but also in terms of stability and the degree to which poor test performance translates into cognitive failures in daily life.