Aphemia from an infarct in the left frontal operculum
The patient presented after an acute onset of expressive aphasia, yet appeared to maintain intact written language expression. He also maintained full comprehension. The remainder of his neurologic examination was otherwise unremarkable.
Psychiatric derangement or mood disorder: While this patient was clearly belligerent and agitated by ER report, psychiatric differentials such as a form of non-catatonic mutism, hostile resistant mutism with anxiety/tension, or even psychosomatic mutism and selective mutism were unlikely in this age group without any prior past psychiatric history other than depression. His depression seemed mild, and was not accompanied by psychotic features.
Broca's aphasia/transcortical aphasia/subcortical aphasia/aphemia (refer to the discussion section).
Altered mental status from metabolic abnormality: While a multitude of metabolic abnormalities are associated with altered mental states either directly or indirectly, there was no evidence for any systemic disturbance based on initial labs, nor were there any past medical history to suggest this possibility. Furthermore, this patient's presentation of a highly restricted neurological deficit strongly evidenced against a diffuse encephalopathic insult typical of metabolic disturbances.
Although initially distinguished from an aphasic disturbance in 1865 by Broca, there have been much subsequent disagreements and misdiagnoses regarding the nature of aphemia. In fact, much debate has surrounded the categorization of aphemia as either a form of dysarthric syndrome, aphasic syndrome, or apraxic syndrome. In the literature, various names have been given to this disorder of speech including, aphasic dysarthria, ataxic aphasia, phonetic disintegration, pure motor aphasia, apraxia of speech, glossolabiopharyngeal apraxia, and articulatory apraxia.[1,17,19] Aphemia is a distinct, independent clinical syndrome, rather than a mild or rapidly improving subset or variant of aphasia. It is a disorder of speech with disruption of a specific network in the motor system that is responsible for articulation. It is not a disorder of language. In this regard, it is correctly regarded as a form of dysarthria, and in its classic form, anarthria at its onset.
Aphemia arises from disconnection of speech outflow from internal language production. Thus, this distinct syndrome of dysarthria without aphasia has uniquely distinct clinical-anatomic correlations. Based on several series of patients with specific motor impairment for articulation, comparative brain MRIs and CTs have identified etiologic associations with focal lesions of the pars opercularis (Brodmann's area 44), anterior inferior and posterior inferior pre-rolandic gyrus (Brodmann's area 6 and 4), or the subcortical white matter associated with these regions.[3,5,9,13,16,17,19,24] Furthermore, less definitive correlations have been noted with insults to the peri-sylvian structures such as the occipito-temporal area 37, and the frontal insular region.[6,20] Much less commonly, there are reports of aphemia due to focal lesions in the supplementary motor area (on both the left and right side in right-handed individuals), right opercular region referred to as "crossed aphemia," and the right insular region in right handed individuals.[4,10,20,22] Overall, aphemic syndrome has been reported to arise from a wide variety of neuropathologies, including acute focal vascular insults (most commonly), fronto-temporal dementia, multiple sclerosis, hematoma, hemiplegic migraine, and arteriovenous aneurysm.[7,15,18,24]
This patient likely had vascular occlusion in the often overlapping distal territories of the prefrontal or orbito-frontal branches of the upper division of the MCA (the common suppliers of the pars opercularis and the inferior pre-rolandic gyrus).[11,14] Although this patient's particular stroke etiology was not uncovered, in-situ thrombotic occlusion of small and large vessels only make up approximately 2-7% of ischemic events in the MCA territory. Embolism is widely supported as the primary etiology of MCA strokes from either atheromatous plaques of ipsilateral carotid disease or cardioembolic sources. Cardioembolism accounts for approximately 50% of total MCA strokes and 34% of deep MCA strokes.[12] While this patient had neither significant MCA nor carotid atherosclerotic disease, he did have a diminished ejection fraction thus raising the suspicion for a cardioembolic etiology.
The clinical manifestation of aphemia is classically an individual who is mute or capable of only minimal dysarthric and hypophonic spoken output at the symptom onset. This initial state is often confused for the manifestation of a severe aphasic syndrome, but clinically distinguishes itself on further specific examination of language output. Broca's aphasia will have additional heavier burdens of agrammatic construction, anomia, and specific syntactic comprehension deficits, further deforming all modes of communication rather than just speech output.[19] This dysfunction in the anterior language center often yields, if not completely nonfluent, specific grammatical aberrancies such as dropped pronouns (e.g., "You, me, I"), linking verbs (e.g., "is, are"), and articles (e.g., "and, the"). Imperative sentence architecture (e.g., "walk dog") dominates as opposed to the intended declarative form (e.g., "you are walking the dog"). This loss of context present in Broca's aphasia is not present in the classic aphemic syndrome.[20] Individuals with Broca's aphasia can often have concurrent mild to moderate deficits in language comprehension, whereas this function is comparatively intact in aphemia. Therefore, testing of ability to follow complex serial commands can help distinguish between these two entities. Moreover, unlike Broca's aphasia in which the difficulties of communication are pervasive across all forms of language outflow, the burden of oral communication is usually relieved through writing in aphemia. The aphemic patient's written language shows normal grammatical structure and fluent spontaneous outflow, normal written naming, and written repetition. If some deficits in writing are present, they are invariably milder when compared to speech output, and may show subtle language abnormalities such as censored articles and linking verbs.[8,19,20] Finally, Broca's aphasia, in its more severe form, is also well known to be associated with hemiparesis of the face and arm. The hemiparesis of aphemic patients, if present, is often mild in degree such as mild lower facial paresis or subtle motor deficiencies of the hand demonstrable only upon attempting fine coordination."
Transcortical motor aphasia, a lesion anterior or superior to Broca's area, is another nonfluent aphasia often mistaken for the aphemic syndrome. Both show clinical disruption of speech output. However, unlike the aphemic syndrome, repetition is vocally intact in transcortical motor aphasia. The arcuate fasciculus responsible for repetition is not affected, and poor naming usually persists in the written communication (unlike the aphemic syndrome). Other more remarkable grammatical errors in the written output are also present, thus revealing a primary language, not speech, deficit of transcortical motor aphasia. Transcortical motor aphasia is also more likely to be associated with a greater degree of hemiparesis of the contralateral face and arm.[8]
Standard of care remains consistent with acute stroke assessment and treatment. Tissue plasminogen activator (tPA) can be considered in the acute setting within 4.5 hours as clinically indicated. The NIHSS scores in most aphemia cases are likely to be relatively low (less than 4), although the latest AHA/ASA guidelines recommend that the decision regarding acute thrombolysis be guided by likelihood of disability particularly devastating to the patient's lifestyle (rather than simply the NIHSS score itself, even if less than 4). In terms of extent of disability, there is some consensus that aphemia, unlike other clinical syndromes of language, is significantly more likely to improve to either completely normal speech or improve to only minimal residual dysarthria over long term follow-up. Such residual dysarthria is reported to show simply mild accent or change in accent inflection.[2,23]
There is currently no reported study to formally guide the appropriate management of patients with low NIHSS score in the setting of aphemia compared to aphasia, partly because of the historical delay in distinguishing these two syndromes in the acute setting. Therefore, when making acute stroke treatment decisions, there is presently no proven indication to distinguish the distinct disorders of speech production (despite implications for differences in long term natural history). Aphemia is thus treated in the acute setting with same clinical judgment as one would apply to any stroke causing difficulty in oral communication.
He had a rapid spontaneous improvement in his NIHSS score between the initial evaluation by ER staff and the time of initial neurologist's examination (from 7 to 3). This paralleled his subjective improvement in the ability to communicate. After neurologic assessment, the question was whether to administer tPA for a likely acute stroke with an improving trend and a low NIH stroke scale score of 3. As his main deficit was a severe inability to communicate, and his job as a sales manager heavily utilized his ability to communicate effectively, a mutual decision was made to administer tPA once his initial head CT ruled out evidence of hemorrhage. Over his subsequent 4-day hospital course, he had additional mild improvement in his speech (NIHSS dysarthria score improved from 2 to 1) as he worked daily with speech therapy. Although the initial head CT did not reveal any infarct, follow-up brain MRI revealed an acute focal infarct (DWI and ADC sequences) in the left frontal operculum and its adjacent subcortical white matter. His MRA revealed absence of significant stenosis of the anterior and posterior circulations. Echocardiogram revealed features of congestive heart failure, without evidence of thrombus. Cardiology was consulted and recommended starting lisinopril. He was also started on low dose (81 mg daily) Aspirin therapy and a moderate dose of statin (atorvastatin 40 mg daily).
On follow-up at six months after his discharge, he has had significant recovery of his speech with minimal deficit in articulation, described to him by others as an attenuation of his natural southern accent. He continued to receive intermittent speech therapy.
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