Conduction aphasia: Difference between revisions
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==Pathophysiology== | ==Pathophysiology== | ||
*The pathogenesis of [ | *The pathogenesis of [[conduction aphasia]] involves damage to [[arcuate fasciculus]]. [[Arcuate fasciculus]] is a [[white matter]] tract connecting [[Broca's]] and [[Wernicke's]] areas, the areas responsible for [[motor]] and [[sensory]] components of [[speech]]. Thus, when [[arcuate fasciculus]] is damaged the connection between [[Broca's]] and [[Wernicke's]] areas is lost. As a consequence, the transmission of information between the 2 speech centers is halted, leading to impairment of repetition.<ref name="urlConduction Aphasia - StatPearls - NCBI Bookshelf">{{cite web |url=https://www.ncbi.nlm.nih.gov/books/NBK537006/#_NBK537006_pubdet_ |title=Conduction Aphasia - StatPearls - NCBI Bookshelf |author= Acharya AB, Maani CV |authorlink= |coauthors= |date= |format= |work= |publisher=statpearls publishing |pages= |language= |archiveurl= |archivedate= |quote= |accessdate=}}</ref> | ||
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway. | *The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway. | ||
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name]. | *On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name]. | ||
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name]. | *On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name]. | ||
==Causes== | ==Causes== | ||
Revision as of 07:03, 30 August 2020
| Conduction aphasia | |
 | |
|---|---|
| Broca's area and Wernicke's area | |
| MeSH | D018886 |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Ahmad Muneeb, MBBS[2] Synonyms and keywords: Dysphasia, Conduction; Associative Aphasia; Aphasia, Associative; Associative Aphasias; Dysphasias, Conduction; Aphasias, Associative; Conduction Aphasia; Conduction Dysphasias; Associative Dysphasias; Associative Dysphasia; Conduction Dysphasia; Dysphasias, Associative; Dysphasia, Associative; Aphasias, Conduction; Conduction Aphasias
Overview
Conduction aphasia, also called associative aphasia, is a relatively rare form of aphasia, thought to be caused by a disruption in the fiber pathways connecting Wernicke's and Broca's areas. The arcuate fasciculus has previously been implicated as this fiber bundle,[1] however more recent evidence suggests that the extreme capsule connects Wernicke's and Broca's areas[2].
Historical Perspective
- Conduction aphasia was first described by Carl Wernicke in the year 1874. Later on in 1885, Lichtheim described this disorder further.[3]
- In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
- In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].
Classification
- [Disease name] may be classified according to [classification method] into [number] subtypes/groups:
- [group1]
- [group2]
- [group3]
- Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].
Pathophysiology
- The pathogenesis of conduction aphasia involves damage to arcuate fasciculus. Arcuate fasciculus is a white matter tract connecting Broca's and Wernicke's areas, the areas responsible for motor and sensory components of speech. Thus, when arcuate fasciculus is damaged the connection between Broca's and Wernicke's areas is lost. As a consequence, the transmission of information between the 2 speech centers is halted, leading to impairment of repetition.[4]
- The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
- On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
- On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
Causes
The most common cause of conduction aphasia is damage to arcuate fasciculus lying deep to left supra marginal gyrus. Other common causes of conduction aphasia include damage to other brain areas including leftsuperior temporal gyrus, left primary auditory cortices, insula and left inferior parietal lobe. [5][6]
Differentiating [disease name] from other Diseases
- [Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
- [Differential dx1]
- [Differential dx2]
- [Differential dx3]
Epidemiology and Demographics
- The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
- In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].
Age
- Patients of all age groups may develop [disease name].
- [Disease name] is more commonly observed among patients aged [age range] years old.
- [Disease name] is more commonly observed among [elderly patients/young patients/children].
Gender
- [Disease name] affects men and women equally.
- [Gender 1] are more commonly affected with [disease name] than [gender 2].
- The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.
Race
- There is no racial predilection for [disease name].
- [Disease name] usually affects individuals of the [race 1] race.
- [Race 2] individuals are less likely to develop [disease name].
Risk Factors
- Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].
Natural History, Complications and Prognosis
- The majority of patients with [disease name] remain asymptomatic for [duration/years].
- Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
- If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
- Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
- Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].
Diagnosis
Diagnostic Criteria
- The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met:
- [criterion 1]
- [criterion 2]
- [criterion 3]
- [criterion 4]
History and Symptoms
- [Disease name] is usually asymptomatic.
- Symptoms of [disease name] may include the following:
- [symptom 1]
- [symptom 2]
- [symptom 3]
- [symptom 4]
- [symptom 5]
- [symptom 6]
Physical Examination
- Patients with [disease name] usually appear [general appearance].
- Physical examination may be remarkable for:
- [finding 1]
- [finding 2]
- [finding 3]
- [finding 4]
- [finding 5]
- [finding 6]
Laboratory Findings
- There are no specific laboratory findings associated with [disease name].
- A [positive/negative] [test name] is diagnostic of [disease name].
- An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
- Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].
Electrocardiogram
There are no ECG findings associated with [disease name].
OR
An ECG may be helpful in the diagnosis of [disease name]. Findings on an ECG suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
X-ray
There are no x-ray findings associated with [disease name].
OR
An x-ray may be helpful in the diagnosis of [disease name]. Findings on an x-ray suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no x-ray findings associated with [disease name]. However, an x-ray may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
Echocardiography or Ultrasound
There are no echocardiography/ultrasound findings associated with [disease name].
OR
Echocardiography/ultrasound may be helpful in the diagnosis of [disease name]. Findings on an echocardiography/ultrasound suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no echocardiography/ultrasound findings associated with [disease name]. However, an echocardiography/ultrasound may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
CT scan
There are no CT scan findings associated with [disease name].
OR
[Location] CT scan may be helpful in the diagnosis of [disease name]. Findings on CT scan suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no CT scan findings associated with [disease name]. However, a CT scan may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
MRI
There are no MRI findings associated with [disease name].
OR
[Location] MRI may be helpful in the diagnosis of [disease name]. Findings on MRI suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
There are no MRI findings associated with [disease name]. However, a MRI may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
Other Imaging Findings
There are no other imaging findings associated with [disease name].
OR
[Imaging modality] may be helpful in the diagnosis of [disease name]. Findings on an [imaging modality] suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
Other Diagnostic Studies
There are no other diagnostic studies associated with [disease name].
OR
[Diagnostic study] may be helpful in the diagnosis of [disease name]. Findings suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
OR
Other diagnostic studies for [disease name] include [diagnostic study 1], which demonstrates [finding 1], [finding 2], and [finding 3], and [diagnostic study 2], which demonstrates [finding 1], [finding 2], and [finding 3].
Treatment
Medical Therapy
- There is no treatment for [disease name]; the mainstay of therapy is supportive care.
- The mainstay of therapy for [disease name] is [medical therapy 1] and [medical therapy 2].
- [Medical therapy 1] acts by [mechanism of action 1].
- Response to [medical therapy 1] can be monitored with [test/physical finding/imaging] every [frequency/duration].
Surgery
- Surgery is the mainstay of therapy for [disease name].
- [Surgical procedure] in conjunction with [chemotherapy/radiation] is the most common approach to the treatment of [disease name].
- [Surgical procedure] can only be performed for patients with [disease stage] [disease name].
Prevention
- There are no primary preventive measures available for [disease name].
- Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].
- Once diagnosed and successfully treated, patients with [disease name] are followed-up every [duration]. Follow-up testing includes [test 1], [test 2], and [test 3].
Presentation
Patients with conduction aphasia show the following characteristics:
- speech is fluent
- comprehension remains good
- oral reading is poor
- Major Impairment in repetition
- many phonemic paraphasias (phone substitution errors)
- transpositions of sounds within a word ("television" → "velitision") are common.
To understand the symptoms, recall that Broca's area is associated roughly with expression, Wernicke's area with comprehension.
With both areas intact but the neural connections between them broken, there is the curious condition where the patient can understand what is being said but cannot repeat it (or repeats it incorrectly). This patient will also end up saying something inappropriate or wrong, realize his/her mistake, but continue making further mistakes while trying to correct it.
References
- ↑ Essentials of Human Physiology by Thomas M. Nosek. Section 8/8ch15/s8c15_14.
- ↑ Schmahmann, J. and Pandya, D. "Fiber Pathways of the Brain". Oxford University Press 2006
- ↑ Hickok G (September 2009). "The functional neuroanatomy of language". Physics of Life Reviews. 6 (3): 121–43. doi:10.1016/j.plrev.2009.06.001. PMC 2747108. PMID 20161054.
- ↑ Acharya AB, Maani CV. "Conduction Aphasia - StatPearls - NCBI Bookshelf". statpearls publishing.
- ↑ Jiménez de la Peña MM, Gómez Vicente L, García Cobos R, Martínez de Vega V (2018). "Neuroradiologic correlation with aphasias. Cortico-subcortical map of language". Radiologia. 60 (3): 250–261. doi:10.1016/j.rx.2017.12.008. PMID 29439808.
- ↑ Damasio H, Damasio AR (June 1980). "The anatomical basis of conduction aphasia". Brain : a Journal of Neurology. 103 (2): 337–50. doi:10.1093/brain/103.2.337. PMID 7397481.