Memory impairment following right cerebellar infarction: a case study.

We reported a patient with a right cerebellar infarction who showed anterograde amnesia. Cognitive dysfunction caused by cerebellar lesions was called cerebellar cognitive affective syndrome, and deactivation of the contralateral prefrontal cortex function due to disconnections of cerebello-cerebral fiber tracts have been hypothesized as mechanism underlying the syndrome. The episodic memory impairment, however, could not be supported by the same mechanism because the prefrontal lesions cannot cause amnesia syndrome. The feature of the impairment of our patient was similar to that of diencephalic amnesia, and a single photon emission computed tomography study showed a relative hypoperfusion in the right cerebellar hemisphere and left anterior thalamus. We considered that the memory deficit was caused by the dysfunction of the thalamus, which is a relay center of the cerebello-cerebral connectivity network.

The role of the thalamus in recovery from tactile extinction and crossed tactile extinction.

A 68-year-old man had a cerebral infarction affecting the right parietal lobe, right insula, and the left prefrontal region. On admission, left hand tactile extinction was noted when the hands were placed both in anatomical and crossed positions, but was noted only in crossed positions from day 20 and later. Five months later, the patient developed another cerebral infarction in the right thalamus, and left hand tactile extinction was again seen both in the anatomical and crossed positions. Our findings suggest that the thalamus was involved in the recovery from the tactile extinction in anatomical positions.

Frontotemporal lobar degeneration with writing disturbance mainly consisting of omission of kana letters.

A right-handed woman developed pseudobulbar palsy and a particular writing disturbance mainly composed of omission of kana letters (OKL) at the age of 79, followed by gradual progression of generalized motor disturbance and mutism. She died at the age of 88. Postmortem examination revealed frontotemporal lobar degeneration. The precentral cortex and premotor area were the most severely degenerated among the affected frontal, parietal, and temporal lobes. The omission of kana letters has been recently reported as a characteristic feature of writing disturbance in Japanese amyotrophic lateral sclerosis (ALS). Our case indicates that OKL is not specific to ALS, and that the prefrontal and precentral cortices, common lesions between our case and ALS, are responsible for OKL. This case also shows that OKL can be caused by a pathomechanism independent from other types of writing error. The neurolinguistic analysis of our case suggests the disturbance of the moraic frame of words in the transcription process of morae into kana letters or kana-letter cards.

High sensitivity of asymmetric 18F-THK5351 PET abnormality in patients with corticobasal syndrome.

Corticobasal syndrome (CBS) is characterized by symptoms related to the asymmetric involvement of the cerebral cortex and basal ganglia. However, early detection of asymmetric imaging abnormalities can be challenging. Previous studies reported asymmetric 18F-THK5351 PET abnormalities in CBS patients, but the sensitivity for detecting such abnormalities in larger patient samples, including early-stage cases, remains unclear. Patients clinically diagnosed with CBS were recruited. All patients displayed asymmetric symptoms in the cerebral cortex and basal ganglia. Asymmetric THK5351 PET abnormalities were determined through visual assessment. Brain MRI, perfusion SPECT, and dopamine transporter (DAT) SPECT results were retrospectively reviewed. The 15 patients had a median age of 72 years (59-86 years) and a disease duration of 2 years (0.5-7 years). Four patients met the probable and 11 met the possible CBS criteria according to Armstrong criteria at the time of PET examination. All patients, including early-stage cases, exhibited asymmetric tracer uptake contralateral to their symptom-dominant side in the cerebral cortex/subcortical white matter and striatum (100%). The sensitivity for detecting asymmetric imaging abnormalities contralateral to the symptom-dominant side was 86.7% for brain MRI, 81.8% for perfusion SPECT, and 90% for DAT SPECT. White matter volume reduction was observed in the subcortical region of the precentral gyrus with increased THK5351 uptake, occurring significantly more frequently than gray matter volume reduction. THK5351 PET may be a sensitive imaging technique for detecting asymmetric CBS pathologies, including those in early stages.

Ambient echolalia in a patient with germinoma around the bilateral ventriculus lateralis: a case report.

Ambient echolalia is a rare condition with few reported cases. We report the case of a 20-year-old man with a germinoma around the bilateral ventriculus lateralis who exhibited ambient echolalia. Clinical features included instinctive grasp reaction and compulsive manipulation of tools in his right hand. Speech or mental deterioration has been cited as a cause of ambient echolalia, but neither dementia nor aphasia was present. We propose that ambient echolalia in our case could be interpreted as a disinhibition of pre-existing essentially intact motor subroutines due to damage of the medial frontal lobe.

Anti-LGI1 Encephalitis Developing Immunoglobulin Responsive Orthostatic Hypotension after Remission.

Anti-leucine-rich glioma-inactivated 1 (LGI1) antibody is associated with limbic encephalitis. We herein report a patient with anti-LGI1 encephalitis who developed severe orthostatic hypotension (OH) responsive to immunoglobulin therapy five years after developing symptoms of encephalitis. A 71-year-old man presented with amnesia caused by limbic encephalitis. The symptoms of encephalitis improved partially without any immunotherapy. Five years later, he developed severe OH, and anti-LGI1 antibody was positive. The catecholamine dynamics indicated that the central autonomic nervous system was the lesion of his OH. Intravenous immunoglobulin therapy improved the OH. This case suggests that anti-LGI1 antibody can be associated with severe OH.

Hyperlexia and ambient echolalia in a case of cerebral infarction of the left anterior cingulate cortex and corpus callosum.

We report the case of a 69-year-old woman with cerebral infarction in the left anterior cingulate cortex and corpus callosum. She showed hyperlexia, which was a distinctive reading phenomenon, as well as ambient echolalia. Clinical features also included complex disorders such as visual groping, compulsive manipulation of tools, and callosal disconnection syndrome. She read words written on the cover of a book and repeated words emanating from unrelated conversations around her or from hospital announcements. The combination of these two features due to a focal lesion has never been reported previously. The supplementary motor area may control the execution of established subroutines according to external and internal inputs. Hyperlexia as well as the compulsive manipulation of tools could be interpreted as faulty inhibition of preexisting essentially intact motor subroutines by damage to the anterior cingulate cortex reciprocally interconnected with the supplementary motor area.

[Alien hand sign observed at the initial stage of a case of Creutzfeldt-Jakob disease].

A 68-year-old man was admitted to our hospital in the mid-October of 2006 because of a one-month history of peculiar movements of the left hand, which had been preceded by one month by awkward motions in the left leg. Upon neurological examination, spontaneous involuntary movement of the left hand was found. His left hand with his index finger stretched moved toward his right side spontaneously. He could not control his left leg freely. Although he showed mild ataxia in his left hand, there was no weakness, no dystonia, and no apraxia. No sensory abnormality was detected except for mild deep-sensation impairment in his left foot. The results of magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) were normal; however, single-photon emission computed tomography (SPECT) showed hypoperfusion in the right hemisphere. At the time of admission, although a clinical diagnosis could not be made, we considered that the involuntary movements of his left hand were consistent with alien hand sign (AHS). Two and a half months after its onset, with the development of rapidly progressive dementia and generalized myoclonus, AHS gradually disappeared. Three months after the AHS onset, MRI with DWI showed restricted diffusion within the cortex involving the cingulated gyrus and bilateral temporal lobes, which was more prominent on the right than on the left side. Four months after the AHS onset, 14-3-3 protein level of the cerebrospinal fluid was elevated, and EEG recordings showed diffuse slowing of basic activity with periodic complexes. The patient was clinically diagnosed as having CJD. The patient died of pneumonia four and a half months after the AHS onset. AHS has rarely been reported in patients with CJD. Our case illustrates the importance of considering CJD in the differential diagnosis, if the patient showed AHS, even with normal MRI findings.

Anti-Ma2 paraneoplastic encephalitis associated with testicular germ cell tumor treated by carboplatin, etoposide and bleomycin.

Anti-Ma2-associated encephalitis is a paraneoplastic disorder that predominantly affects the limbic system, diencephalon and brainstem, and is usually associated with tumors of the testis. We report a 35-year-old man with a right testicular mass who presented with multiple neurological complains, and clinical, serological and radiological features compatible with anti-Ma2-associated encephalitis. After three courses of carboplatin, etoposide and bleomycin for metastatic testicular germ-cell tumor, all elevated tumor markers normalized and the retroperitoneal metastases disappeared, but the neurological disorder deteriorated. To our knowledge, this is the first case in which orchiectomy followed by carboplatin, etoposide and bleomycin for a testicular tumor with anti-Ma2 encephalitis was performed.

A case of auditory agnosia with impairment of perception and expression of music: cognitive processing of tonality.

There is fairly general agreement that the melody and the rhythm are the independent components of the perception of music. In the theory of music, the melody and harmony determine to which tonality the music belongs. It remains an unsettled question whether the tonality is also an independent component of the perception of music, or a by-product of the melody and harmony. We describe a patient with auditory agnosia and expressive amusia that developed after a bilateral infarction of the temporal lobes. We carried out a detailed examination of musical ability in the patient and in control subjects. Comparing with a control population, we identified the following impairments in music perception: (a) discrimination of familiar melodies; (b) discrimination of unfamiliar phrases, and (c) discrimination of isolated chords. His performance in pitch discrimination and tonality were within normal limits. Although intrasubject statistical analysis revealed significant difference only between tonality task and unfamiliar phrase performance, comparison with control subjects suggested a dissociation between a preserved tonality analysis and impairment of perception of melody and chords. By comparing the results of our patient with those in the literature, we may say that there is a double dissociation between the tonality and the other components. Thus, it seems reasonable to suppose that tonality is an independent component of music perception. Based on our present and previous studies, we proposed the revised version of the cognitive model of musical processing in the brain.

[Music therapy and neuropsychology: a proposal to music therapy based on the cognitive processing of music].

In the last decade, a considerable number of studies have been made on the cognitive processing of music. A patient with pure amusia due to the infarction of anterior portion of bilateral temporal lobes revealed the disturbance of the discrimination of chords. Using positron emission tomography, these regions were activated when musically naive normal subjects listened to the harmony compared to the rhythm of identical music. So, we concluded that anterior temporal portion might participate in the recognition of chords. Several articles reported that the musician's brain was different from nonmusicians' functionally and anatomically. This difference was considered to be caused by the musical training for a long time. Recent studies clarified that the reorganization might occur by musical training for a few months. Melodic intonation therapy (MIT) is a method aimed to improve speech output of aphasic patients, using short melodic phrase with a word. The literatures of mental processing of music suggested that right hemisphere might participate in the expression of music, namely singing and playing instrumentals. So, it was supposed that MIT utilized the compensational function of right hemisphere for damaged left hemisphere. We also reported that mental singing improved the gait disturbance of patients with Parkinson's disease. Music therapy is changing from a social science model based on the individual experiences to a neuroscience-guided model based on brain function and cognitive processing of the perception and expression of music.

[A case of combined sensation disturbance and clumsiness of the left hand caused by an infarction localized to brodmann areas 1 and 2].

A 70-year-old woman was admitted to our hospital with a complaint of numbness and clumsiness of the left hand. On physical examination 23 days after the onset of cerebral infarction, she showed no apparent muscle weakness. Although her elementary somatosensory function was mostly intact with a minimal joint position sensation disturbance, she showed disturbances in tactile recognition, two-point discrimination, and weight perception. She also had difficulty in discrete finger movement of her left hand, especially when her eyes were closed. Brain MRI disclosed a small infarction localized to Brodmann areas 1 and 2 in the right postcentral gyrus. In the left median nerve short-latency somatosensory evoked potentials (s-SEPs), the N20 potential was normally evoked. This finding also indicated that the area 3b was preserved. The sensory symptoms observed in this patient were compatible with the hierarchical somatosensory processing model in the postcentral gyrus proposed by Iwamura et al, in which the elementary sensation recognized in area 3 is transferred to areas 1 and 2, and then processed to discriminative sensation. The disturbed discrete finger movement in this patient probably resulted from impaired tactile recognition which could be compensated for by visual information.

[A case of a postmedian sternotomy C8 plexopathy localized with electrodiagnostic tests].

A postmedian sternotomy plexopathy is a C8 plexopathy following an operation that requires a median sternotomy, in which the C8 anterior primary ramus is injured. Since the clinical picture of a C8 plexopathy is quite similar to an ulnar neuropathy, electrodiagnostic tests are crucial for localizing the lesion and confirming the diagnosis. This is the first published report in Japan that shows the clinical picture of a postmedian sternotomy C8 plexopathy and the utility of electrophysiological tests to diagnose this disease. A 54 year-old man developed numbness in the right ring and little fingers just after an operation through a median sternotomy to treat an aortic dissection. His symptoms did not improve and he was reevaluated 11 months after the operation. Neurological examinations revealed a weakness of the right ulnar-innervated hand muscles, and tingling dysesthesia of the ring and little fingers. In electrodiagnostic tests, the ulnar SNAP was severely depressed on the affected side, and in addition the amplitude of the median SNAP over the ring finger (Med-D4) was also reduced by more than half of that observed in his healthy side (62% side-to-side difference). In our investigation of 26 control subjects, the side-to-side difference of the Med-D4 SNAP amplitude did not exceed 50% for any subject. Needle electromyography revealed profuse denervation activities in the FCU, ADM and EPB, and moderately reduced recruitment and giant motor unit potentials in the EI. The postmedian sternotomy plexopathy had been long described, but its precise localization using modern electrodiagnostic techniques has been presented only recently in the literature. Our results are largely the same as those found in previous reports, which show the predominant involvement of the ulnar sensory and motor fibers and electromyographic changes in C8-radial muscles (EPB and EI). Furthermore, the antidromic SNAP of Med-D4 was significantly reduced in amplitude on the affected side, and supported the diagnosis of the C8 plexopathy. The Med-D4 method is the only method that can document a nonulnar C8 involvement solely by NCS. Whereas the potential role of the Med-D4 method has been suggested in this condition, this is the first report that actually showed its utility.

White matter lesions and cognitive impairment may be related to recovery from unilateral spatial neglect after stroke.

BACKGROUND: Unilateral spatial neglect (USN) is frequently found in ischemic stroke patients. Because USN is related to poor functional outcomes, evaluating recovery from USN after stroke is critical. METHODS: Patients with acute ischemic stroke with lesions in the right cerebral hemisphere on MRI and exhibiting left USN were administered the Behavior Inattention Test (BIT) at 1 and 3weeks after admission. BIT improvement was defined as a ≥1-point increase in ≥4 of the 6 BIT subtests from 1 to 3weeks, or a total BIT score ≥131 at 3weeks. Factors associated with improvement of left USN were analyzed. RESULTS: Eighteen patients (8 men; mean age, 70±12years) were enrolled in this study. BIT was performed at 5.3±0.7 and 18.2±0.7days after admission. Twelve patients were classified to the improvement (I) group, and 6 to the non-improvement (NI) group. BIT scores increased substantially from 76.6±40.5 in the acute phase to 109.2±43.3 in the subacute phase. The I group displayed higher BIT scores than the NI group in both acute and subacute phases (P<0.01 each). The degree of white matter lesions on the Fazekas scale was lower in the I group (0.6±0.7) than in the NI group (1.7±1.2, P=0.028). Increased BIT scores correlated significantly with increased Mini Mental State Examination scores (r=0.487, P=0.040). CONCLUSIONS: Amelioration of left USN might be related to white matter lesions and cognitive impairment. Sample size in the current study was small, limiting the generalizability of results, and larger studies are warranted in the future.

Neural consequences of somatosensory extinction: an fMRI study.

There are currently two main interpretations proposing mechanisms underlying tactile extinction: sensory and attention deficit hypotheses. Kinsbourne proposed an opponent processor model to support the attention deficit hypothesis. He insisted that bilateral hemispheres interact reciprocally through contralaterally oriented vectors, and in patients presenting extinction, balance is impaired, causing inattention. From Kinsbourne's point of view, extinction is not caused by sensory disturbance but inattention, therefore even in extinction patients, simultaneous bilateral stimuli should reach the bilateral primary sensory cortices (SI). Using functional magnetic resonance imaging (fMRI), tactile stimuli were administered to both hands of healthy subjects as well as a tactile extinction patient. The patient with tactile extinction extinguished right palm stimuli following simultaneous palm stimulation. During the fMRI study, we gave tactile stimuli to the right palm, the left palm, and simultaneously to both palms. In normal subjects, simultaneous bilateral stimuli activated the bilateral SI and bilateral secondary sensory cortices (SII). In the patient with right tactile extinction, simultaneous bilateral stimuli activated the bilateral SI along with the bilateral SII and right superior parietal lobule. Our study suggests that activation of SI is insufficient to engender an awareness of sensory stimuli. From the view point of Kinsbourne, stimulus driven activity in one hemisphere suppresses activity in the other hemisphere via callosal connections. Our results support the notion that an undamaged superior parietal lobule in the patient with tactile extinction suppresses the damaged parietal lobe function and causes extinction.

A case of amusia caused by the infarction of anterior portion of bilateral temporal lobes.

It remains an unsettled question which brain regions participate in music perception. During singing a familiar song, the retrieval from long-term memory is necessary, but the mechanism of that retrieval is still unclear. We carried out a detailed examination of musical ability in a patient with amusia and control subjects and identified the lesion sites of our patient using MRI. Compared with controls, the patient manifested the following impairments in music perception: (i) the recognition and discrimination of familiar melodies; (ii) the discrimination of unfamiliar phrases; (iii) the discrimination of isolated chords. During singing familiar nursery songs, the patient showed the replacement of one phrase of the melody. In MRI, the patient had old infarction in the anterior portion of the temporal lobes bilaterally. In conclusion, the anterior temporal lobes participate in the perception and expression of music. During singing, the song is retrieved from long-term memory by a unit of one phrase. The dysfunction of that retrieval caused the replacement of the succeeding phrases of the original with the wrong tune, and we named this phenomenon paramelodia.

The Neural Basis of Typewriting: A Functional MRI Study.

To investigate the neural substrate of typewriting Japanese words and to detect the difference between the neural substrate of typewriting and handwriting, we conducted a functional magnetic resonance imaging (fMRI) study in 16 healthy volunteers. All subjects were skillful touch typists and performed five tasks: a typing task, a writing task, a reading task, and two control tasks. Three brain regions were activated during both the typing and the writing tasks: the left superior parietal lobule, the left supramarginal gyrus, and the left premotor cortex close to Exner's area. Although typing and writing involved common brain regions, direct comparison between the typing and the writing task revealed greater left posteromedial intraparietal cortex activation in the typing task. In addition, activity in the left premotor cortex was more rostral in the typing task than in the writing task. These findings suggest that, although the brain circuits involved in Japanese typewriting are almost the same as those involved in handwriting, there are brain regions that are specific for typewriting.

Somatosensory and skin temperature disturbances caused by infarction of the postcentral gyrus: a case report.

Somatosensory functions are subdivided into 2 large groups: the elementary somatosensory functions, which consist of light touch, pain, thermal sensation, joint position sense, and vibration sense, and the intermediate somatosensory functions, which include 2-point discrimination, tactile localization, weight, texture, and shape perception. In this report, we describe a patient with somatosensory dysfunction after infarction of the postcentral gyrus. On physical examination a month after the onset of the infarction, voluntary movements were skillful, and both the elementary and intermediate somatosensory functions were disturbed in the right hand. The patient also displayed a decrease in the skin temperature of the right hand. The sensory-evoked potential in response to electrical stimulation of the right median nerve was normal, and brain MRI showed that the infarction was located in the posterior half of the left postcentral gyrus. These findings suggested that the lesion was situated at areas 1 and 2, and that area 3b was preserved. Thermography revealed that the skin temperature of the right hand was decreased predominantly on the ulnar side, and that recovery from cooling with ice water was delayed. By comparing the results of our patient with a case report that showed no disturbance of the elementary somatosensory functions with a localized lesion in the postcentral gyrus, we suggest that area 1 participates in the elementary somatosensory functions and that skin temperature may be controlled somatotopically in the somatosensory cortex.

The anterior portion of the bilateral temporal lobes participates in music perception: a positron emission tomography study.

BACKGROUND AND PURPOSE: The mechanism underlying the perception of music has been the subject of study for many years. We investigated the role of the anterior portion of the temporal lobes in the perception of music in nonmusicians by use of positron emission tomography (PET). METHODS: We used the subtraction technique for PET to investigate the role of the anterior portion of the bilateral temporal lobes in music perception. Nonmusicians performed two kinds of musical tasks: harmony listening and soprano part listening. RESULTS: During the harmony-listening task, the anterior portion of the temporal lobes, cingulate gyri, and cerebellum were bilaterally activated. During the soprano part-listening task, the bilateral superior parietal lobules, and the right precuneus were significantly activated. CONCLUSION: The anterior portion of the bilateral temporal lobes is vital in the discrimination of melodies and chords. Differences between activated brain regions exist between musicians and nonmusicians when listening to a particular vocal part of a musical phrase.

[How to examine a patient with higher cortical dysfunction at bedside].

In practice, a neuropsychological evaluation may serve one or more purpose. The first systematic applications of neuropsychological assessment dealt with diagnosis. Before the days of sophisticated neuroimaging, the localization of a cerebral lesion was neuropsychology's most important function. Recent developments in neuroradiological techniques have greatly reduced the contributions of neuropsychological assessment to diagnosis and lesion localization. Today, neuropsychological assessment is most usually called upon for the detailed behavioral description necessary for intelligent patient care, for rational treatment, and for appropriate rehabilitation training. When neurologists examines patients with higher cortical dysfunction, they should bear the following points in mind. At first, good clinical history often holds the key to diagnosis. This is especially true in the neurologic and the neuropsychologic history. The examiners should not hesitate to ask the patient history before and during the neuropsychological examinations. Secondly sometimes the patients with neuropsychological dysfunction do not recognize their disturbances. For example, the patients with apraxia or optic ataxia usually do not complain their disturbances. Only by storing the range of neuropsychological dysfunction in their mind can neurologists recognize these behavioral disturbances. Thirdly in neurology when we localize lesions of the nervous system, it is helpful to think about the major syndrome supervene with lesions at different anatomical levels, from the muscle to the cortex. Also in neuropsychology, for example, when we localize lesions of with speech disturbance it is useful to think about from the simplest level (the muscle) to the cortex. At last test in neuropsychological assessment can be used to establish a comparison standard--i.e. for estimating premorbid ability. The Wechsler test (WAIS-R) is one of the most frequently used measures in neuropsychological batteries. It is a core instrument, giving information about the overall level of intellectual functioning disability, and providing clues to altered functions.