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Sudden loss of speech: causes, symptoms, diagnosis
Medical expert of the article
Last reviewed: 07.07.2025
In case of sudden loss of speech, it is first necessary to determine whether it is anarthria (that is, the inability to pronounce words due to a disruption of the coordinated activity of the respiratory, voice-forming and articulatory apparatus due to their paresis, ataxia, etc.) or aphasia (that is, a disruption of speech praxis).
This task is not easy, even when the patient is conscious and able to follow instructions, which is generally rare in acute pathology. Simple questions can be answered with yes/no answers, which are 50% random. Moreover, even with aphasia, patients can grasp the meaning of what they hear exceptionally well, using the "key word" strategy, by which they understand the general meaning of the phrase due to existing situational ("pragmatic") skills, which are not affected by speech impairment.
Examination by means of simple commands is difficult if the patient is hemiplegic and/or immobilized. In addition, concomitant apraxia may also limit the physician's capabilities. In the case of oral apraxia, the patient will not be able to follow even fairly simple instructions (e.g., "open your mouth" or "stick out your tongue").
The ability to read is difficult to study, since reading requires the preservation of response to oral gestures and motor skills, but studying written speech can help make the right decision. In right-sided hemiplegia, the following test is used: the patient is asked to arrange the words of a complete sentence in the correct order, which he receives in written form on separate sheets of paper, mixed up. However, in some cases, even an experienced aphasia specialist cannot immediately make the right decision (for example, when the patient does not even try to pronounce at least a sound). It should be remembered that over time, the picture can change quickly, and instead of aphasia, which the patient had at the time of admission, dysarthria, that is, a purely articulatory speech disorder, can quickly come to the fore. The patient's age plays a large role in making a diagnosis.
The main reasons for sudden loss of speech:
- Migraine with aura (aphasic migraine)
- Stroke in the left hemisphere
- Postictal state
- Brain tumor or abscess
- Thrombosis of the intracerebral sagittal sinus
- Herpes simplex virus encephalitis
- Psychogenic mutism
- Psychotic mutism
Migraine with aura
In young patients, migraine with aura is the first to be suspected. In these cases, the following typical combination of symptoms is present: acute or subacute loss of speech (usually without hemiplegia), accompanied by headache, which has repeatedly occurred in the patient in the past and which may or may not be accompanied by changes in neurological status. If such an attack of migraine has occurred for the first time in a given patient, a study of the family history (if possible) can provide useful information, since in 60% of cases this disease is familial.
The EEG will most likely reveal a focus of slow-wave activity in the left temporoparietal region, which may persist for 3 weeks, while neuroimaging does not reveal any pathology. Pronounced focal changes in the EEG in the absence of abnormalities in the results of a neuroimaging study on the 2nd day of the disease, in principle, allow a correct diagnosis to be made, with the exception of cases of herpes encephalitis (see below). The patient should not have cardiac murmurs that may indicate the possibility of cardiogenic embolism, which can be observed at any age. A possible source of embolism is identified (or excluded) using echocardiography. Auscultation of vascular murmurs over the vessels of the neck is less reliable compared to ultrasound Dopplerography. Transcranial ultrasound Dopplerography should be performed if possible. A patient suffering from migraine and belonging to the age group of 40 to 50 years may have asymptomatic stenotic vascular lesion, but the typical nature of headache, rapid reversal of symptoms and the absence of structural changes in the brain according to the results of neuroimaging methods of examination in combination with the above-described changes in the EEG allow us to make the correct diagnosis. If the symptoms do not progress, there is no need for CSF examination.
Left hemisphere stroke
In case of speech disorder in an elderly patient, the most probable diagnosis is stroke. In most cases of speech disorder in stroke, the patient has right-sided hemiparesis or hemiplegia, hemihypesthesia, sometimes hemianopsia or a defect in the right visual field. In such cases, neuroimaging is the only way to reliably differentiate intracerebral hemorrhage from ischemic stroke.
Speech loss almost always occurs with a left-hemisphere stroke. It can also be observed with a right-hemisphere stroke (i.e., with damage to the non-dominant hemisphere), but in these cases speech is restored much faster, and the probability of complete recovery is very high.
Mutism may precede the appearance of aphasia in case of damage to Broca's area, it has also been described in patients with damage to the additional motor area, in severe pseudobulbar palsy. In general, mutism most often develops in case of bilateral brain damage: thalamus, anterior areas of the cingulate gyrus, damage to the putamen on both sides, cerebellum (cerebellar mutism in case of acute bilateral damage to the cerebellar hemispheres).
A gross violation of articulation may occur with a violation of blood circulation in the vertebrobasilar basin, but a complete absence of speech is observed only with occlusion of the basilar artery, when akinetic mutism develops, which is a rather rare phenomenon (bilateral damage to the mesencephalon). Mutism as a lack of vocalization is also possible with bilateral paralysis of the muscles of the pharynx or vocal cords ("peripheral" mutism).
Postictal state (state after a seizure)
In all age groups except infants, speech loss may be a postictal phenomenon. The seizure itself may go unnoticed, and tongue or lip biting may be absent; an increase in blood creatine phosphokinase may indicate that a seizure has occurred, but this finding is unreliable in terms of diagnosis.
Quite often, EEG facilitates diagnosis: generalized or local slow- and sharp-wave activity is recorded. Speech is quickly restored, and the doctor is faced with the task of determining the cause of the epileptic seizure.
Brain tumor or abscess
The anamnesis of patients with a brain tumor or abscess may lack any valuable information: there was no headache, no behavioral changes (aspontaneity, flattening of affect, apathy). There may also be no obvious inflammatory process in the ENT organs. Sudden loss of speech may occur: due to a rupture of a vessel supplying blood to the tumor and the resulting hemorrhage into the tumor; due to a rapid increase in perifocal edema; or - in the case of a left-hemispheric tumor or abscess - due to a partial or generalized epileptic seizure. A correct diagnosis is possible only with a systematic examination of the patient. An EEG study is necessary, which can record a focus of slow-wave activity, the presence of which cannot be unambiguously interpreted. However, the presence of very slow delta waves in combination with a general slowing of the brain's electrical activity may indicate a brain abscess or a hemispheric tumor.
In the case of both a tumor and an abscess, computed tomography can reveal a volumetric intracerebral process in the form of a low-density focus with or without contrast absorption. In the case of abscesses, there is often more pronounced perifocal edema.
Thrombosis of the intracerebral sagittal sinus
There is the following typical triad of symptoms that may indicate intracerebral sinus thrombosis: partial or generalized epileptic seizures, hemispheric focal symptoms, decreased level of wakefulness. EEG records generalized low-amplitude slow-wave activity over the entire hemisphere, also extending to the opposite hemisphere. In neuroimaging, sinus thrombosis is indicated by hemispheric edema (mainly in the parasagittal region) with diapedetic hemorrhages, signal hyperintensity in the sinus(es) and a deltoid-shaped zone that does not accumulate the injected contrast and corresponds to the affected sinus.
Herpes simplex virus (HSV) encephalitis
Since herpes encephalitis caused by HSV predominantly affects the temporal lobe, aphasia (or paraphasia) is often the first symptom. The EEG reveals focal slow-wave activity, which, upon repeated EEG recording, is transformed into periodically occurring three-phase complexes (triplets). Gradually, these complexes spread to the frontal and contralateral leads. Neuroimaging reveals a low-density zone, which soon acquires the characteristics of a volumetric process and spreads from the deep parts of the temporal lobe to the frontal lobe, and then contralaterally, primarily involving zones related to the limbic system. Signs of an inflammatory process are found in the cerebrospinal fluid. Unfortunately, verification of HSV infection by direct visualization of viral particles or by immunofluorescence analysis is possible only with a significant time delay, while antiviral therapy should be started immediately upon the first suspicion of viral encephalitis (given that the mortality rate for HSV encephalitis reaches 85%).
Psychogenic mutism
Psychogenic mutism is manifested by the absence of responsive and spontaneous speech with the preserved ability to speak and understand speech addressed to the patient. This syndrome can be observed in the picture of conversion disorders. Another form of neurotic mutism in children is elective (selective, occurring when communicating with only one person) mutism.
Psychotic mutism is mutism in the picture of negativism syndrome in schizophrenia.
Diagnostic tests for sudden loss of speech
General and biochemical blood analysis; ESR; fundus examination; cerebrospinal fluid analysis; CT or MRI; ultrasound Doppler imaging of the main arteries of the head; a consultation with a neuropsychologist can be of invaluable assistance.
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