-
Der Nervenarzt Feb 2024Nowadays, Henry Head is best known for his Head zones. The concept was understood very differently by Head in comparison to what current medical books falsely describe... (Review)
Review
Nowadays, Henry Head is best known for his Head zones. The concept was understood very differently by Head in comparison to what current medical books falsely describe them to be. In reality, there is no direct relationship between one particular skin zone and one single organ. It is certain that the drawings considered depictions of the Head zones in today's medical textbooks were actually not created by Head. From a neurological point of view, Head is important for two reasons: his self-experiment in 1909 to damage one of his own peripheral nerves followed by regeneration was heroic. It has helped generations of neurologists to have a better understanding of the pathophysiology of peripheral nerve damage and thus make a better assessment of the prognosis of such injuries. Head's second contribution pertains to the radicular organization at the level of the spinal cord. The pathophysiology of herpes zoster radiculitis enabled him to develop the concept of the dermatomes on the basis of preliminary work around 1900. Henry Head's contribution was the systematic compilation of the existing publications of the time and amendment of his own cases. As he was the most important neurologist at that time, at least in the English speaking world, and was well connected with people in the German neurology community, it was probably easy for him to make his dermatome maps well known. In retrospect, Head was less successful in neuropsychology with holistic concepts for higher cognitive functions which were in vogue during his lifetime. His late work on aphasia is now considered refuted. Head's criticism of the strict localization was well in syncronization with the zeitgeist of the early twentieth century. Establishing the fact that Broca's aphasia and Wernicke's aphasia are not easily diagnostically distinguishable from each other was more an achievement of subsequent generations of neurologists and neuropsychologists as well as technical advances.
Topics: Humans; Aphasia; Neurology; Spinal Cord
PubMed: 37823921
DOI: 10.1007/s00115-023-01556-7 -
BMC Neurology Feb 2024Various post-stroke dysfunctions often result in poor long-term outcomes for stroke survivors, but the effect of conventional treatments is limited. In recent years,...
Various post-stroke dysfunctions often result in poor long-term outcomes for stroke survivors, but the effect of conventional treatments is limited. In recent years, lots of studies have confirmed the effect of repetitive transcranial magnetic stimulation (rTMS) in stroke rehabilitation. As a new pattern of rTMS, theta burst stimulation (TBS) was proved recently to yield more pronounced and long-lasting after-effects than the conventional pattern at a shorter stimulation duration. To explore the role of TBS in stroke rehabilitation, this review summarizes the existing evidence from all the randomized controlled trials (RCTs) so far on the efficacy of TBS applied to different post-stroke dysfunctions, including cognitive impairment, visuospatial neglect, aphasia, dysphagia, spasticity, and motor dysfunction. Overall, TBS promotes the progress of stroke rehabilitation and may serve as a preferable alternative to traditional rTMS. However, it's hard to recommend a specific paradigm of TBS due to the limited number of current studies and their heterogeneity. Further high-quality clinical RCTs are needed to determine the optimal technical settings and intervention time in stroke survivors.
Topics: Humans; Stroke Rehabilitation; Transcranial Magnetic Stimulation; Stroke; Time Factors
PubMed: 38297193
DOI: 10.1186/s12883-023-03492-0 -
Annals of Neurology Oct 2023Nonfluent aphasia is characterized by simplified sentence structures and word-level abnormalities, including reduced use of verbs and function words. The predominant...
OBJECTIVE
Nonfluent aphasia is characterized by simplified sentence structures and word-level abnormalities, including reduced use of verbs and function words. The predominant belief about the disease mechanism is that a core deficit in syntax processing causes both structural and word-level abnormalities. Here, we propose an alternative view based on information theory to explain the symptoms of nonfluent aphasia. We hypothesize that the word-level features of nonfluency constitute a distinct compensatory process to augment the information content of sentences to the level of healthy speakers. We refer to this process as lexical condensation.
METHODS
We use a computational approach based on language models to measure sentence information through surprisal, a metric calculated by the average probability of occurrence of words in a sentence, given their preceding context. We apply this method to the language of patients with nonfluent primary progressive aphasia (nfvPPA; n = 36) and healthy controls (n = 133) as they describe a picture.
RESULTS
We found that nfvPPA patients produced sentences with the same sentence surprisal as healthy controls by using richer words in their structurally impoverished sentences. Furthermore, higher surprisal in nfvPPA sentences correlated with the canonical features of agrammatism: a lower function-to-all-word ratio, a lower verb-to-noun ratio, a higher heavy-to-all-verb ratio, and a higher ratio of verbs in -ing forms.
INTERPRETATION
Using surprisal enables testing an alternative account of nonfluent aphasia that regards its word-level features as adaptive, rather than defective, symptoms, a finding that would call for revisions in the therapeutic approach to nonfluent language production. ANN NEUROL 2023;94:647-657.
Topics: Humans; Aphasia, Broca; Language
PubMed: 37463059
DOI: 10.1002/ana.26744 -
Applied Neuropsychology. Adult 2024The present study examined the deficits of people with aphasia in tense (past, present, and future) and agreement (person, number, and gender) in Jordanian Arabic. Forty...
The present study examined the deficits of people with aphasia in tense (past, present, and future) and agreement (person, number, and gender) in Jordanian Arabic. Forty participants were selected and two tasks were administered for this study using Boston Diagnostic Aphasia Examination (BDAE)-Arabic version. The first task was sentence completion in which sentences have a blank and need to be filled by the participants. The second task was grammaticality judgment, in which participants should determine whether sentences are grammatically correct or not. Results indicated significantly that the Jordanian participants with aphasia violate gender aspect more than person and number in both sentence completion task ( = 0.025) and grammaticality judgment task ( = 0.000), it was also reported that past tense was violated significantly more than present and future in sentence completion task ( = 0.000) as well as grammaticality judgment task ( = 0.012). It is concluded that Arabic speakers with agrammatism were tested with reference to time and agreement and the results showed that they performed as hypothesized, showing a selective deficit for production of inflected forms of past tense.
Topics: Humans; Aphasia, Broca; Jordan; Language; Language Tests; Judgment
PubMed: 34694931
DOI: 10.1080/23279095.2021.1993856 -
American Journal of Speech-language... Jun 2024Repetitive transcranial magnetic stimulation (rTMS) can enhance aphasia recovery. Most studies have used inhibitory stimulation targeting the right inferior frontal...
Neuromodulation of the Right Motor Cortex of the Lips With Repetitive Transcranial Magnetic Stimulation to Reduce Phonological Impairment and Improve Naming in Three Persons With Aphasia: A Single-Case Experimental Design.
PURPOSE
Repetitive transcranial magnetic stimulation (rTMS) can enhance aphasia recovery. Most studies have used inhibitory stimulation targeting the right inferior frontal gyrus. However, the motor cortex, observed to contribute to the prediction of aphasia recovery, is involved in word production and could be an appropriate target for rTMS. We aimed to observe behavioral changes in a picture naming task induced by inhibitory rTMS targeting the right motor cortex of the lips in people with poststroke aphasia.
METHOD
Using a single-case experimental design, we included three participants with chronic poststroke aphasia who had phonological deficits. Each participant performed a verbal picture naming task 3 times a week for 2, 3, or 4 weeks (pseudorandom across participants) to establish a baseline naming ability for each participant. These were not therapy sessions, and no feedback was provided. Then, each participant received the intervention, inhibitory continuous theta burst stimulation targeting the right motor cortex of the lips, 3 times a week for 2 weeks. Naming testing continued 3 times a week, for these latter 2 weeks. No therapy was performed at any time during the study.
RESULTS
Visual analysis of the graphs showed a positive effect of rTMS for P2 and P3 on picture naming accuracy and a tendency toward improvement for P1. Statistical analysis showed an improvement after rTMS for P1 (τ = 0.544, 013, = 0.288) and P2 (τ = 0.708, 001, = 0.235). For P3, even if the intervention allowed some improvement, this was statistically nonsignificant due to a learning effect during the baseline naming testing, which lasted the longest, 4 weeks. Regarding specific language features, phonological errors significantly decreased in all patients.
CONCLUSIONS
The motor cortex of the lips could be an appropriate target for rTMS to improve naming in people with poststroke aphasia suffering from a phonological deficit. This suggests the possibility to individualize the target for rTMS, according to the patient's linguistic impairment.
PubMed: 38875479
DOI: 10.1044/2024_AJSLP-23-00215 -
Neurological Sciences : Official... Mar 2024Most stroke patients suffer from an imbalance in blood supply, which causes severe brain damage leading to functional deficits in motor, sensory, swallowing, cognitive,...
BACKGROUND
Most stroke patients suffer from an imbalance in blood supply, which causes severe brain damage leading to functional deficits in motor, sensory, swallowing, cognitive, emotional, and speech functions. Repetitive transcranial magnetic stimulation (rTMS) is thought to restore functions impaired during the stroke process and improve the quality of life of stroke patients. However, the efficacy of rTMS in treating post-stroke function impairment varies significantly. Therefore, we conducted a meta-analysis of the number of patients with effective rTMS in treating post-stroke dysfunction.
METHODS
The PubMed, Embase, and Cochrane Library databases were searched. Screening and full-text review were performed by three investigators. Single-group rate meta-analysis was performed on the extracted data using a random variable model. Then subgroup analyses were performed at the levels of stroke acuity (acute, chronic, or subacute); post-stroke symptoms (including upper and lower limb motor function, dysphagia, depression, aphasia); rTMS stimulation site (affected side, unaffected side); and whether or not it was a combination therapy.
RESULTS
We obtained 8955 search records, and finally 33 studies (2682 patients) were included in the meta-analysis. The overall analysis found that effective strength (ES) of rTMS was 0.53. In addition, we found that the ES of rTMS from acute/subacute/chronic post-stroke was 0.69, 0.45, and 0.52. We also found that the ES of rTMS using high-frequency stimulation was 0.56, while the ES of rTMS using low-frequency stimulation was 0.53. From post-stroke symptoms, we found that the ES of rTMS in sensory aspects, upper limb functional aspects, swallowing function, and aphasia was 0.50, 0.52, 0.51, and 0.54. And from the site of rTMS stimulation, we found that the ES of rTMS applied to the affected side was 0.51, while the ES applied to the unaffected side was 0.54. What's more, we found that the ES of rTMS applied alone was 0.53, while the ES of rTMS applied in conjunction with other therapeutic modalities was 0.53.
CONCLUSIONS
By comparing the results of the data, we recommend rTMS as a treatment option for rehabilitation of functional impairment in patients after stroke. We also recommend that rehabilitation physicians or clinicians use combination therapy as one of the options for patients.
PubMed: 38512529
DOI: 10.1007/s10072-024-07455-2 -
Cortex; a Journal Devoted To the Study... Dec 2023Agrammatic or asyntactic comprehension is a common language impairment in aphasia. We considered three possible hypotheses about the underlying cause of this deficit,...
Agrammatic or asyntactic comprehension is a common language impairment in aphasia. We considered three possible hypotheses about the underlying cause of this deficit, namely problems in syntactic processing, over-reliance on semantics, and a deficit in cognitive control. We tested four individuals showing asyntactic comprehension on their comprehension of syntax-semantics conflict sentences (e.g., The robber handcuffed the cop), where semantic cues pushed towards a different interpretation from syntax. Two of the four participants performed above chance on such sentences indicating that not all agrammatic individuals are impaired in structure-based interpretation. We collected additional eyetracking measures from the other two participants, who performed at chance on the conflict sentences. These measures suggested distinct underlying processing profiles in the two individuals. Cognitive assessments further suggested that one participant might have performed poorly due to a linguistic cognitive control impairment while the other had difficulty due to over-reliance on semantics. Together, the results highlight the importance of multimodal measures for teasing apart aphasic individuals' underlying deficits. They corroborate findings from neurotypical adults by showing that semantics can strongly influence comprehension and that cognitive control could be relevant for choosing between competing sentence interpretations. They extend previous findings by demonstrating variability between individuals with aphasia-cognitive control might be especially relevant for patients who are not overly reliant on semantics. Clinically, the identification of distinct underlying problems in different individuals suggests that different treatment paths might be warranted for cases who might look similar on behavioral assessments.
Topics: Adult; Humans; Aphasia, Broca; Comprehension; Language; Semantics; Linguistics
PubMed: 37981441
DOI: 10.1016/j.cortex.2023.09.017 -
Frontiers in Neurology 2023Apraxia of speech (AOS) is a motor speech disorder impairing the coordination of complex articulatory movements needed to produce speech. AOS typically co-occurs with a...
INTRODUCTION
Apraxia of speech (AOS) is a motor speech disorder impairing the coordination of complex articulatory movements needed to produce speech. AOS typically co-occurs with a non-fluent aphasia, or language disorder, making it challenging to determine the specific brain structures that cause AOS. Cases of pure AOS without aphasia are rare but offer the best window into the neural correlates that support articulatory planning. The goal of the current study was to explore patterns of apraxic speech errors and their underlying neural correlates in a case of pure AOS.
METHODS
A 67-year-old right-handed man presented with severe AOS resulting from a fronto-insular lesion caused by an ischemic stroke. The participant's speech and language were evaluated at 1-, 3- and 12-months post-onset. High resolution structural MRI, including diffusion weighted imaging, was acquired at 12 months post-onset.
RESULTS
At the first assessment, the participant made minor errors on the Comprehensive Aphasia Test, demonstrating mild deficits in writing, auditory comprehension, and repetition. By the second assessment, he no longer had aphasia. On the Motor Speech Evaluation, the severity of his AOS was initially rated as 5 (out of 7) and improved to a score of 4 by the second visit, likely due to training by his SLP at the time to slow his speech. Structural MRI data showed a fronto-insular lesion encompassing the superior precentral gyrus of the insula and portions of the inferior and middle frontal gyri and precentral gyrus. Tractography derived from diffusion MRI showed partial damage to the frontal aslant tract and arcuate fasciculus along the white matter projections to the insula.
DISCUSSION
This pure case of severe AOS without aphasia affords a unique window into the behavioral and neural mechanisms of this motor speech disorder. The current findings support previous observations that AOS and aphasia are dissociable and confirm a role for the precentral gyrus of the insula and BA44, as well as underlying white matter in supporting the coordination of complex articulatory movements. Additionally, other regions including the precentral gyrus, Broca's area, and Area 55b are discussed regarding their potential role in successful speech production.
PubMed: 37576017
DOI: 10.3389/fneur.2023.1187399 -
Brain Stimulation 2023The continuous decline of executive abilities with age is mirrored by increased neural activity of domain-general networks during task processing. So far, it remains...
BACKGROUND
The continuous decline of executive abilities with age is mirrored by increased neural activity of domain-general networks during task processing. So far, it remains unclear how much domain-general networks contribute to domain-specific processes such as language when cognitive demands increase. The current neuroimaging study explored the potential of intermittent theta-burst stimulation (iTBS) over a domain-general hub to enhance executive and semantic processing in healthy middle-aged to older adults.
METHODS
We implemented a cross-over within-subject study design with three task-based neuroimaging sessions per participant. Using an individualized stimulation approach, each participant received once effective and once sham iTBS over the pre-supplementary motor area (pre-SMA), a region of domain-general control. Subsequently, task-specific stimulation effects were assessed in functional MRI using a semantic and a non-verbal executive task with varying cognitive demand.
RESULTS
Effective stimulation increased activity only during semantic processing in visual and dorsal attention networks. Further, iTBS induced increased seed-based connectivity in task-specific networks for semantic and executive conditions with high cognitive load but overall reduced whole-brain coupling between domain-general networks. Notably, stimulation-induced changes in activity and connectivity related differently to behavior: While stronger activity of the parietal dorsal attention network was linked to poorer semantic performance, its enhanced coupling with the pre-SMA was associated with more efficient semantic processing.
CONCLUSIONS
iTBS modulates networks in a task-dependent manner and generates effects at regions remote to the stimulation site. These neural changes are linked to more efficient semantic processing, which underlines the general potential of network stimulation approaches in cognitive aging.
Topics: Middle Aged; Humans; Aged; Semantics; Motor Cortex; Cognition; Brain; Brain Mapping; Magnetic Resonance Imaging; Transcranial Magnetic Stimulation
PubMed: 37704032
DOI: 10.1016/j.brs.2023.09.009 -
Dementia & Neuropsychologia 2024Frontotemporal dementia (FTD) is a progressive neurodegenerative disorder defined by the selective deterioration of the frontal and temporal lobes of the brain. This... (Review)
Review
Frontotemporal dementia (FTD) is a progressive neurodegenerative disorder defined by the selective deterioration of the frontal and temporal lobes of the brain. This comprehensive review explored the effect of FTD on language, speech, and behavior. Early symptoms include difficulty in word finding, reduced speech output, and comprehension deficits, often leading to aphasia. The study discussed the profound behavioral changes observed in FTD patients, including apathy, disinhibition, compulsive behaviors, and loss of empathy, the importance of an accurate and early diagnosis, and its challenges. We even reviewed the potential for targeted therapies and the essential role of multidisciplinary care in managing the language, speech, and behavioral aspects of FTD. By examining objective data and comprehensive research on the subject, this study offers valuable insights into FTD's profound effects on language, speech, and behavior, assisting in improved clinical management and potential therapeutic strategies for this devastating condition.
PubMed: 38659629
DOI: 10.1590/1980-5764-DN-2023-0072