Auditory sound agnosia without aphasia following a right temporal lobe lesion

A 55-year-old right-handed man showed inability to recognize the meaning of non-verbal sounds without impairment of language comprehension after a cerebrovascular accident. His auditory acuity was intact and no other sign of agnosia, apraxia or aphasia was detectable. His errors on a test of sound recognition were acoustic rather than semantic. Brain CT scan showed a small lesion in the posterior part of the right temporal lobe. This case suggests that auditory sound agnosia without language disorder can ensure a lesion confined to the right hemisphere, and that the deficit is discriminative rather than associative in nature.     

A case of slowly progressive aphasia accompanied with auditory agnosia]

A 68-year-old right-handed woman was admitted to our hospital because of difficulty to speak and understand conversation over 10 years. She was able to make herself by writing. No change in her personality or behavioral abnormality was observed so that she could live without help. Although her WAIS score and auditory brain stem response were normal, she could not understand the speech or distinguish the sound. She also spoke plenty of words fluently, resulting in undifferentiated jargon. She did not make any effort in speaking. Her speech was, however, unclear and hard to understand. Brain MRI scan disclosed a moderate atrophy of bilateral temporal lobe and enlargement of Sylvius fissure. A three-dimension reconstructed brain surface image showed enlargement of the perisylvian fissure, and atrophy of the gyrus frontalis inferior, operculum, gyrus temporal superior, bilaterally. Reduced cerebral blood flow was demonstrated on 99mTc-ECD SPECT in the left thalamus and bilateral fronto-temporal lobe. A diagnosis of slowly progressive aphasia with auditory agnosia was made. Our case suggests that bilateral disturbance of neuronal network between the primary auditory area and the secondary auditory area is responsible to the consequence of auditory agnosia.     

Non-verbal auditory agnosia with EEG abnormalities and epilepsy; an unusual case of Landau-Kleffner syndrome]

A case of unusual Landau-Kleffner syndrome was reported. She was an 8 year-old girl and showed non-verbal agnosia, diffuse EEG abnormalities and convulsions. Her responses to both verbal and non-verbal sounds remained inconsistent and unstable. When a continuous spike-wave complexes on EEG was detected, she paid no attention to any sound in spite of her fair consciousness. Auditory brainstem response and magnetic resonance imaging of her brain were normal. Auditory agnosia was correlated well with EEG abnormalities, and valproic acid and clonazepam were effective for EEG improvement. After the EEG improvement, clinical responses to sounds recovered well; firstly she could pay attention to sounds and then she could distinguish between verbal and non-verbal sounds. Finally, she could speak a few words after the learning letters.     

Alexia with agraphia produced by localized infarction in the inferior posterior region of the left temporal lobe

There have been several reports on alexia with agraphia due to hemorrhage or trauma in the inferior posterior region of the left temporal lobe since Yamadori (1982) first reported a case of cerebral hemorrhage. We presented the first case of alexia with agraphia due to a circumscribed infarct in the inferior posterior region of the left temporal lobe. A 65-year-old right-handed man had an acute onset of inability to read Japanese "kana" letters and to write any letters. He had no difficulty in speaking or understanding. Neurological examination on admission was normal except for homonymous quadrantanopia in the right upper field. Neuropsychological findings: Spontaneous speech was fluent without dysprosody. There were no disturbances in auditory understanding or in repetition. He could read Japanese "kanji" characters correctly, however, he could not read any "kana" letters. Writing was also disturbed severely even as to his address, name or telephone number. Calculation was also difficult. There were no disturbances in naming colors, no ideomotor or constructional apraxia nor visual agnosia. X-ray computed tomography (CT) scan showed a faint low density area with ring enhancement suggesting a cerebral infarct in the inferior posterior region of the left temporal lobe. Patient's hospital course was characterized by a marked improvement of alexia, especially of "kana" letters as compared with that of "kanji" characters. Dissociative improvement of alexia compared with agraphia in this case could be explained by the fact that the lesion was in close contact with the occipital lobe and that he also had pure alexia in the early stage.     

Clinical and audiological findings in a case of auditory agnosia

Summary A case is reported of severe agnosia for verbal and non-verbal sounds without associated aphasic disorder. A CT scan revealed bilateral, temporal lobe lesions from two ischaemic accidents that had occurred 9 months apart. The search for subtle deficits in this patient showed normal sensitivity to changes in the intensity and frequency of simple sounds; in contrast, his ability to discriminate sound duration and musical note sequences was severely impaired. The simultaneous recording of the whole auditory-evoked response pattern revealed no abnormality in the early components, which reflect the activation of the auditory nuclei and pathways of the brain stem. However, the middle and late components were delayed and slowed. These results and others in the literature suggest that the neocortex in man, as in other mammals, plays an essential role in the temporal aspects of hearing. Also, the two main ingredients commonly recognized in auditory agnosia, i.e. word deafness and the inability to interpret non-verbal sounds, are caused by the disruption of elementary, bilaterally represented cortical functions which start the processing of every kind of auditory information.     

A case of auditory agnosia with the lesion of bilateral auditory radiation

A 53-year-old man showed central auditory disturbance with recurrent cerebral hemorrhage. At his acute stage he had deafness and auditory anosognosia. Two or three months later, there was no deafness and auditory anosognosia, but he could not comprehend words, environmental sounds and music. Auditory brainstem responses showed no peripheral or brainstem damage, and the lesion of bilateral auditory radiation was detected by MRI. His auditory agnosia did not improve over one and a half year. There is no report like such permanent auditory agnosia with the lesion of bilateral subcortical temporal lobe.     

Two cases of cerebral embolism showing global aphasia without hemiparesis]

We report two cases of typical global aphasia without hemiparesis due to cerebral embolism. Case 1 was a 65-year-old right-handed man with a history of old myocardial infarction. No spontaneous speech was noted by his family. Neurological examination upon admission revealed confusional state, global aphasia, conjugate deviation to the left and slight drift of the outstretched right limbs. The right hemiparesis rapidly recovered after admission. CT scan performed on the second hospital day showed discrete low density areas in the left posterior frontal lobe and left temporo-parietal regions. The extent and severity of his global aphasia were unchanged. The second case was an 82-year-old right-handed man with a history of atrial fibrillation. He was admitted to our hospital one hour after he was found unable to speak. Neurological examination upon admission revealed global aphasia, conjugate deviation to the left and suspected right homonymous hemianopia by confrontation. There was no sign of hemiparesis. CT scan showed extensive low density area in the left temporo-parietal regions. In both cases, cerebral angiography failed to demonstrate any occlusion of intra- and extra-cranial blood vessels. IMP-SPECT showed a depression of cerebral blood flow in the left anterior and posterior watershed areas in case 1 and 2. In the literature, there have been 20 cases of global aphasia without hemiparesis including our two cases. In many cases, the initial symptom was inability or difficulty in speaking.(ABSTRACT TRUNCATED AT 250 WORDS)     

Detection of differential speech‐specific processes in the temporal lobe using fMRI and a dynamic “sound morphing” technique

Contrary to the classical view, recent neuroimaging studies claim that phonological processing, as part of auditory speech perception, is subserved by both the left and right temporal lobes and not the left temporal lobe alone. This study seeks to explore whether there are variations in the lateralization of response to verbal and nonverbal sounds by varying spectral complexity of those sounds. White noise was gradually transformed into either speech or music sounds using a “sound morphing” procedure. The stimuli were presented in an event‐related design and the evoked brain responses were measured using fMRI. The results demonstrated that the left temporal lobe was predominantly sensitive to gradual manipulation of the speech sounds while the right temporal lobe responded to all sounds and manipulations. This effect was especially pronounced within the middle region of the left superior temporal sulcus (mid‐STS). This area could be further subdivided into a more posterior area, which showed a linear response to the manipulation of speech sounds, and an anteriorly adjacent area which showed the strongest interaction between the speech and music sound manipulations. Such a differential and selective response was not seen in other brain areas and not when the sound “morphed” into a music stimulus. This gives further experimental evidence for the assumption of a posterior‐anterior processing stream in the left temporal lobe. In addition, the present findings support the notion that the left mid STS area is more sensitive to speech signals compared to the right homologue. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.     

Neurologic, audiologic, and electrophysiologic sequelae of bilateral temporal lobe lesions

A 67-year-old woman with demonstrated intact peripheral and brain-stem auditory pathways presented with sudden deafness secondary to sequential bilateral temporal lobe infarcts. Initial examination revealed no behavioral response to sounds and a mild Wernicke's aphasia. Hearing gradually returned but auditory agnosia persists. Changes seen on the computed tomographic scan and the middle latency auditory evoked response over a seven-month period were analyzed and suggest that the peak component of the middle latency response arises from Heschl's gyrus.     

Recognition memory of serially or simultaneously presented words or figures, of epilepsy patients with or without mesial temporal sclerosis

Previous studies, examining short-term recognition memory in patients with partial seizures as a consequence of mesial temporal sclerosis (MTS) have reported inconsistent findings. Dependent on the paradigms used for measuring recognition memory, some studies have demonstrated that the mesial temporal structures are not critically involved in short-term recognition memory. In addition, other studies found a lateralization effect that is consistent with the generally accepted association between left temporal lobe lesions and verbal memory deficits, and right temporal lobe lesions and non-verbal memory impairments. In the present study verbal and non-verbal recognition memory was tested in 41 patients with left or right temporal lobe epilepsy with MTS (22 left; 19 right) versus 44 patients with left or right temporal lobe epilepsy but without MTS (28 left; 16 right). Verbal and non-verbal recognition tasks were presented in both a serial and simultaneous condition to test a hypothesized local/global paradigm. Multiple analyses of variance (MANOVA) showed that unilateral MTS has no marked effects on verbal or non-verbal recognition memory of patients with seizures. An interaction effect between MTS and the lateralization of epileptic activity was found on memory performance: MTS only leads to deficits in recognition memory in patients with right-sided epileptiform activity. As hypothesized, patients with left temporal lobe abnormalities, have specific deficits with recognizing serially presented information.     

Episodic receptive aphasia in a child with Landau-Kleffner Syndrome: PET correlates

We report a four-year-old boy with Landau-Kleffner Syndrome (LKS) characterized by episodic receptive aphasia lasting for few weeks followed by gradual recovery of baseline language functions. Neuropsychological evaluation during an episode showed severe impairment in verbal skills and comprehension, but relative preservation of non-verbal skills. Although he could carry on a conversation during remission, neuropsychological evaluation demonstrated findings reflective of receptive language deficits. Prolonged EEG disclosed frequent sharp-wave activity in the left and right temporal regions but no electrographic seizures. Glucose metabolism PET scan during the fourth episode of aphasia revealed intense hypermetabolism in the left temporal neocortex. Awake EEG during the PET tracer uptake period showed 6.0 spikes/min in the left temporal region and 4.0 spikes/min in the right. A repeat PET scan during remission showed hypometabolism in the left temporal cortex. Awake EEG during the FDG uptake period showed 16.0 spikes/min in the right temporal region and 0.3 spikes/min in the left. During his fifth aphasic episode, EEG (without PET) showed 0.16 spikes/min in the right temporal region and none in the left. Intermittent short episodes of predominantly receptive aphasia with near-total recovery between episodes can be one of the clinical presentations of LKS. This case illustrates the dynamic changes of glucose metabolism in the temporal lobe during episodes of aphasia and remission in a case with LKS. The clinical course of our patient with transient EEG and PET findings suggest that glucose metabolism in LKS cannot be attributed solely to interictal epileptiform activities on scalp EEG.     

Auditory agnosia restricted to environmental sounds following cortical deafness and generalized auditory agnosia

We encountered a case of auditory agnosia restricted to environmental sounds, which was associated with the development of bilateral subcortical lesions after suffering a bilateral putaminal hemorrhage. The patient had a history of a putaminal hemorrhage on her left side without any major disability. Three years later, she suffered a putaminal hemorrhage on the other side. The clinical picture started with cortical deafness, then changed to generalized auditory agnosia for verbal and environmental sounds, and finally developed into auditory agnosia confined to the perception of environmental sounds. Her errors in a test of sound recognition were discriminative rather than associative in nature. Neuro-radiological examinations revealed bilateral subcortical lesions involving the fibers from the medial geniculate body to the temporal lobes after bilateral putaminal hemorrhage. This case suggested that the subcortical lesion involving bilateral acoustic radiation could cause either cortical deafness, auditory agnosia of all sounds, or auditory agnosia restricted to environmental sounds.     

Tactile agnosia and tactile aphasia: symptomatological and anatomical differences.

Two patients with tactile naming disorders are reported. Case 1 (right hand tactile agnosia due to bilateral cerebral infarction) differentiated tactile qualities of objects normally, but could neither name nor categorize the objects. Case 2 (bilateral tactile aphasia after operation of an epidural left parietal haematoma) had as severe a tactile naming disturbance as Case 1, but could categorize objects normally, demonstrating that tactile recognition was preserved. Case 1 may be the first case of tactile agnosia clearly differentiated from tactile aphasia. CT scans of Case 1 revealed lesions in the left angular gyrus, and in the right parietal, temporal, and occipital lobes. Case 2 had lesions in the left angular gyrus and of posterior callosal radiations. Our findings suggest that tactile agnosia appears when the somatosensory association cortex is disconnected by a subcortical lesion of the angular gyrus from the semantic memory store located in the inferior temporal lobe, while tactile aphasia represents a tactual-verbal disconnection.     

A case of primary subarachnoid hemorrhage due to cerebral amyloid angiopathy]

A 77-year-old man who was suffering from an intracerebral hemorrhage of the left subcortex without hypertension was admitted to our hospital. The only neurological symptom was right arm monoparesis. Brain MRI demonstrated a subarachnoid hemorrhage (SAH) in the left frontal lobe. On the day of admission, conventional cerebral angiography revealed no abnormalities in brain arteries. His symptom was disappeared immediately after admission. He was discharged without neurological deficit on day 25. However, he was rehospitalized in our hospital on the same day because he experienced a right subcortical hemorrhage. The neurological symptoms were consciousness disturbance, aphasia and right hemiparesis. Brain CT disclosed a subcortical hemorrhage in the left temporal lobe. CT stereo-guided drainage was performed. Then, we examined tissue removed from the brain's surface. Histologically, beta-amyloid protein was deposited on the walls of the meningeal and cortical vessels, and it replaced all the layers of those walls. Therefore, a diagnosis of cerebral amyloid angiopathy (CAA) was made. His condition gradually improved, but CT showed an asymptomatic ICH in the right parietal lobe on day 36. On day 47, he had a symptomatic ICH in the left caudate nuclei and right frontal lobe. He died on day 66 because of pneumonia. Intracranial hemorrhages due to CAA have been reported and the majority of the lesions have been lober hemorrhage. To the best of our knowledge, few reports have been published regarding primary SAH caused by CAA. The cause of SAH should be considered as CAA when SAH appears without hypertension or in elderly patients.     

A case of dementia with motor neuron disease associated with agraphia--the omission of kana letters]

We report a 55-year-old right-handed Japanese man with motor neuron disease and dysgraphia of kana letters. He was admitted to our hospital because of dysarthria and dysphasia. On admission, the results of general physical examination were within normal limits. Neurological examination revealed severe dysarthria, dysphasia, impaired movement of the tongue without fasciculation and slight distal muscle weakness in the bilateral upper limbs. There were no fasciculation of the muscle. Deep tendon reflexes were hyperactive without Babinski's signs. Sensation, coordination, and gait were normal. Neurophysiological studies demonstrated normal motor nerve conduction velocities and sensory action potential. The results of needle electromyography of the upper limbs were compatible with motor neuron disease (MND). Magnetic resonance imaging (MRI) showed atrophy of the bilateral temporal region of the brain. 99mTc-HMPAO SPECT (Single Photon Emission Computed Tomography) showed reduced uptake of tracer in the bilateral temporal region. On neuropsychological examination, his behavior was normal, and orientation and intelligence were also preserved, but his speech was severely impaired. Reading comprehension was slightly impaired. In regard to writing comprehension, he had no difficulty in copying of words though dictation was found to be impaired. He omitted one kana letter in a word. Agraphia is accompanied by various factors such as aphasia, dementia, agnosia, alexia. But in this case at least for early stage, agraphia existed without other higher cortical dysfunction. He did not show severe dementia in his early stage of his disease, but developed it later in the disease's progression. In this case, agraphia might be due to the atrophic changes in the temporal lobe.     

Agnosia for familiar faces and odors in a patient with right temporal lobe dysfunction

The authors studied a 53-year-old man with progressive prosopagnosia and inability to recognize his favorite foods by smell. He could not identify pictures of familiar faces, but he could match unfamiliar faces and distinguish them from familiar ones. He could not identify familiar odors, but he could detect them and could perceive them as pleasant or familiar. Neuroimaging revealed temporal lobe changes, especially on the right. Right temporal lesions may produce face and odor agnosia by preventing perceptual familiarity units from accessing semantic associations.     

Dissociation between personal and extrapersonal neglect in a crossed aphasia study

Abstract Several reports document crossed aphasia following a right cerebral infarct. However, few of them provide a detailed investigation of associated neuropsychological disorders. A personal neglect disorder with no difficulty in orienting attention in the contralesional space has not been frequently reported independently of lesion side for the language deficit. In most cases, the deficit is described in the acute period. We report the case of a patient who showed severe crossed aphasia several months after cerebral damage. In addition to his language deficit, he suffered from finger agnosia, acalculia, and right/left confusion. Although he was able to orient attention in the contralesional space, he had a persistent personal neglect disorder with severe difficulty in attending to his own body. Results suggest that right hemisphere language dominance does not preclude ipsilateral specialisation for other functions. Furthermore, the dissociation between the two spatial functions provides further confirmation that they are subserved by two independent systems.     

Dissociation Between Personal and Extrapersonal Neglect in a Crossed Aphasia Study

Several reports document crossed aphasia following a right cerebral infarct. However, few of them provide a detailed investigation of associated neuropsychological disorders. A personal neglect disorder with no difficulty in orienting attention in the contralesional space has not been frequently reported independently of lesion side for the language deficit. In most cases, the deficit is described in the acute period. We report the case of a patient who showed severe crossed aphasia several months after cerebral damage. In addition to his language deficit, he suffered from finger agnosia, acalculia, and right/left confusion. Although he was able to orient attention in the contralesional space, he had a persistent personal neglect disorder with severe difficulty in attending to his own body. Results suggest that right hemisphere language dominance does not preclude ipsilateral specialisation for other functions. Furthermore, the dissociation between the two spatial functions provides further confirmation that they are subserved by two independent systems.