Shingo Yamagata

Poststroke apathy and regional cerebral blood flow

BACKGROUND AND PURPOSE Although apathy has been reported as one of the neuropsychiatric symptoms following stroke, there have been no studies on regional cerebral blood flow (rCBF) in patients with apathy. In this study we estimated the severity of apathy using the Apathy Scale and examined its relationship to rCBF in 40 stroke patients (mean age, 71.4 years). METHODS Neuropsychiatric batteries were performed including the Apathy Scale, verbal intelligence and frontal function tests, a depression scale, and an assessment of activities of daily living. The cortical rCBFs were measured by the 133Xe inhalation method. RESULTS Twenty patients (50%) showed apathy. These patients showed significantly lower scores on verbal intelligence and frontal function tests and a significantly higher depression score than the nonapathetic group. On MRI images there was no relationship between the apathy score and specific regional distribution of lesions. The rCBFs of the bilateral hemisphere were significantly lower in the apathetic group than in the nonapathetic group. The apathetic group showed a significantly reduced rCBF in the right dorsolateral frontal and left fronto-temporal regions. Furthermore, the apathy score for all patients was significantly negatively correlated with rCBF in the same regions. CONCLUSIONS These findings demonstrate that apathy is a frequent symptom among elderly stroke patients and may be accompanied by cognitive impairments, depressive state, and frontal dysfunction. The hypoactivity in the frontal lobe and anterior temporal regions may contribute to symptoms of apathy after stroke.

Impaired Novelty Processing in Apathy After Subcortical Stroke

Background and Purpose— Apathy is associated with decreased novelty-seeking behaviors and is a prevailing behavioral symptom after stroke affecting cortical and subcortical regions. We studied the relationship between apathetic state after subcortical stroke and neural orienting response to novel events using an event-related evoked potential (ERP) technique. Methods— Twenty-nine patients with subcortical ischemic stroke were grouped according to whether they showed apathy or not. We analyzed apathy state scaled by the modified Starkstein apathy score and auditory P3 ERP components evoked by task-relevant target stimuli (target P3) and task-irrelevant novel stimuli (novelty P3). Results— The apathetic group showed a significantly lower score of verbal fluency test and global cognitive function test compared with the nonapathetic group. The novelty P3 latency was significantly prolonged, and its amplitude was reduced over the frontal site in the apathy group. The apathy scale was correlated with the novelty P3 latency and amplitude at the frontal site. The target P3 measures were related to global cognitive function. Conclusions— The present study suggests that apathy after subcortical stroke is associated with impaired neural processing of novel events within the frontal–subcortical system and that the novelty P3 is a useful physiological measure for assessing apathy after stroke.

Transthyretin Thr60Ala Appalachian-type mutation in a Japanese family with familial amyloidotic polyneuropathy

A Japanese case with familial amyloidotic polyneuropathy (FAP) associated with the transthyretin mutation Thr60Ala (Appalachian-type mutation) is described. This is the first reported case of a non-Caucasian harboring this type of TTR mutation. The patient developed severe late-onset restrictive cardiomyopathy as well as sensorimotor and autonomic polyneuropathy, which were essentially similar to the previously reported clinical pictures of Appalachian-type FAP.

Event-related evoked potential study of repetition priming to attended and unattended words

The filtering stage of ignored stimuli is one of main issues in the selective attention mechanism. We investigated whether unattended ignored stimuli show repetition priming effects on event-related brain potentials (ERPs), using a lexical decision task involving Japanese Kanji words. The repeated words in the unattended field generated a negative shift of the ERP over the frontal scalp sites. This suggested that unattended stimuli were processed implicitly to some degree and that different neural mechanisms contribute to repetition priming effects to attended and unattended stimuli.

Somatosensory disinhibition and frontal alien hand signs following medial frontal damage.

We report augmentation of somatosensory evoked potentials (SEP) in a patient with frontal alien hand signs after left medial frontal lobe damage. The SEP components occurring later than 30 msec post stimuli were enhanced over the parietal and frontal scalp sites of the lesioned hemisphere. This finding suggests that deficits in inhibitory control of somatosensory processing in parietal and frontal lobes contributes in some way to frontal alien hand signs.

Distinctive Patterns of Three-Dimensional Arterial Spin-Labeled Perfusion Magnetic Resonance Imaging in Subtypes of Acute Ischemic Stroke

BACKGROUND Ischemic penumbra in acute ischemic stroke (AIS) can be evaluated using arterial spin-labeled (ASL) perfusion magnetic resonance imaging (MRI). We used three-dimensional ASL-MRI to examine patients with different stroke subtypes and the clinical utility of the method within 24 hours of AIS onset. SUBJECTS AND METHODS The 55 male and 48 female patients (mean age, 79.0 years) underwent diffusion-weighted imaging (DWI), fluid-attenuated inversion recovery imaging, magnetic resonance angiography, and pulsed continuous ASL perfusion imaging to determine stroke subtype, hypoperfused ASL area, and neurological deficit severity (National Institutes of Health Stroke Scale). Arterial transit artifacts, indicative of occlusive regions or collateral flow, and other stroke indices were compared. RESULTS ASL hypoperfusion was detected in 3 of 9 patients with transient ischemic attack (TIA), 2 of 27 patients with lacunar infarction (LI), 19 of 31 patients with atherothrombotic infarction (AT), and 30 of 36 patients with cardiogenic embolic infarction (CE). ASL abnormalities were significantly less frequent in LI than in AT and CE, and more frequent in CE than in TIA. ASL abnormalities were more prevalent in patients with medium-to-large DWI-assessed lesions than in those with small lesions on DWI. Patients with medium-sized lesions following AT and CE had a high frequency of diffusion-perfusion mismatch. In 4 of the 5 patients who underwent intravenous thrombolytic therapy, ASL hypoperfusion and diffusion-perfusion mismatch were improved and the occluded arteries were recanalized. CONCLUSIONS ASL perfusion studies may provide useful clinical information allowing diffusion-perfusion mismatch detection and treatment selection in AIS patients, depending on stroke subtype.

The clinical significance of arterial transit artifact on arterial spin labeling in patients with acute ischemic stroke

Arterial spin labeling (ASL) is a noninvasive magnetic resonance imaging (MRI) technique used to assess brain perfusion quantitatively in humans. Many studies have reported the safety and utility of ASL in acute ischemic stroke (AIS); however, few reports have investigated the clinical significance of arterial transit artifact (ATA) in AIS. In this report, we focus on the utility of ATA in AIS.

MRI changes specific to vascular parkinsonism.

血管性パーキンソニズム (VP) のMRI画像上の特徴を明らかにする目的で, VP12例, パーキンソニズムを伴わない脳梗塞 (NP) 12例, パーキンソン病 (PD) 15例について黒質緻密層幅, 小梗塞巣の分布と数, 脳室周囲信号域 (PVH) を定量的に検討した.結果 : 1) 黒質緻密層幅はVP・NPに対して, PDで有意な萎縮が認められたが, VPとNPの間には差はみられなかった.2) 小梗塞の分布はVP・NPとも被殻および放線冠に多発する例が殆どで両部位での差はみられなかったが, 基底核総数および全総数でVPに有意に多く認められた.PDでは潜在性梗塞が平均1.2個みられた.3) PVH長径に関してはVP・NPはPDに対して, 基底核レベル前方, 基底核レベル前方+側脳室レベル前方, およびPVH総計において有意に大であった.VPはNPに対し基底核レベル前方および基底核レベル前方+側脳室レベル前方でPVH長径が大であった.4) 黒質緻密層幅, 基底核梗塞総数, PVH径に関して, 3群間の判別分析を行った結果, 黒質緻密層幅>基底核梗塞総数>基底核レベル前方PVHの順に寄与率が高く, VP群とNP群の判別には基底核梗塞総数>基底核レベル前方PVH>黒質緻密層幅の順であった。以上のことから血管性パーキンソニズムの画像上の特徴として, 小梗塞総数の増加, 前方部PVHの増大があげられ, 病態の成立に関与している可能性が考えられた.