Akinetic mutism and gait disturbance in a patient with delayed post-hypoxic leukoencephalopathy.

We report on a patient with delayed post-hypoxic leukoencephalopathy (DPHL) who showed akinetic mutism and gait disturbance, neural injuries that were demonstrated on diffusion tensor tractography (DTT). A patient was exposed to carbon monoxide (CO) and rapidly recovered; however, two weeks after onset, he began to show cognitive impairment and gait disturbance. At six weeks after CO exposure, he showed akinetic mutism and gait inability. DTT at 6-weeks post-exposure showed discontinuations in neural connectivities of the caudate nucleus to the medial prefrontal and orbitofrontal cortex in both hemispheres. In addition, the corticoreticulospinal tract revealed severe thinning in both hemispheres.

Microbial Community Changes in Silkworms Suspected of Septicemia and Identification of Serratia sp.

Diseases that occur in silkworms include soft rot, hardening disease, digestive diseases, and sepsis. However, research on the causes of bacterial diseases occurring in silkworms and the resulting changes in the microbial community is lacking. Therefore, we examined the morphological characteristics of sepsis and changes in the microbial community between silkworms that exhibit a unique odor and healthy silkworms; thus, we established a relationship between disease-causing microorganisms and sepsis. After producing a 16S rRNA amplicon library for samples showing sepsis, we obtained information on the microbial community present in silkworms using next-generation sequencing. Compared to that in healthy silkworms, in silkworms with sepsis, the abundance of the Firmicutes phylum was significantly reduced, while that of Proteobacteria was increased. Serratia sp. was dominant in silkworms with sepsis. After bacterial isolation, identification, and reinfection through the oral cavity, we confirmed this organism as the disease-causing agent; its mortality rate was 1.8 times higher than that caused by Serratia marcescens. In summary, we identified a new causative bacterium of silkworm sepsis through microbial community analysis and confirmed that the microbial community balance was disrupted by the aberrant proliferation of certain bacteria.

Cerebellar Peduncle Injuries in Patients with Mild Traumatic Brain Injury.

BACKGROUND: The cerebellum is connected to the brain stem by three pairs of cerebellar peduncles (CPs)-superior (SCP), middle (MCP), and inferior (ICP)-which carry proprioceptive information to regulate movement and maintain balance and posture. Injury or damage to the CPs caused by tumors, infarcts, or traumatic brain injuries (TBI) results in poor coordination and balance problems. Current data on CP-related injuries and their effect on balance control are sparse and restricted to a few case studies. There have been no studies to date that have investigated CP injuries in a large sample of patients with balance problems following a mild TBI. Hence, we investigated CP-related injuries in patients with balance problems following mild TBI using diffusion tensor tractography (DTT). METHODS: Twenty-one patients with TBI and 21 normal subjects were recruited for this study. Balance was evaluated using the Balance Error Scoring System (BESS). Three DTT-related parameters-fractional anisotropy (FA), apparent diffusion coefficient (ADC), and fiber number (FN) of the CPs-were measured. RESULTS: The FN values of the SCP and ICP in the patient group were significantly lower than those in the control group (p < 0.05). No significant differences in the FA, ADC, and FN values of the MCP were observed between the patient and control groups (p > 0.05). CONCLUSIONS: Using DTT, we demonstrated injuries to the SCP and ICP in mild TBI patients with balance problems. Our results suggest that DTT could be a useful tool for detecting injuries to the CPs that may not be identified on conventional brain magnetic resonance imaging in mild TBI patients.

Prefronto-thalamic tract injury and cognitive outcome according to external ventricular drainage location in stroke patients.

OBJECTIVES: We investigated the characteristics of prefronto-thalamic tract (PF-TT) injuries in stroke patients using diffusion tensor tractography (DTT) and assessing cognitive outcome according to location of the external ventricular drainage (EVD). METHODS: Forty-five consecutive stroke patients who underwent EVD and 24 control subjects were recruited. The patients were classified into three groups: group A (EVD on the lesion or one side, 17 patients), group B (EVD on the hemisphere opposite to the lesion, 12 patients), and group C (EVD on both sides, 16 patients). Mini-Mental State Examination (MMSE) results were performed at the beginning (average 2.27 months from onset) and end (average 4.19 months from onset) of rehabilitation. Three parts of the PF-TT (dorsolateral PF-TT[DLPF-TT], ventrolateral PF-TT[VLPF-TT], orbitofronto-thalamic tract[OF-TT]) were reconstructed and the fractional anisotropy (FA) and tract volume (TV) measurements were obtained. RESULTS: With the EVD on the stroke-affected side, the values of FA and TV of all three parts of the PF-TTs in three patient groups were lower than those of the control group (p < 0.05). With the EVD on the unaffected side, the FA values of the DLPF-TT in groups B and C and the OF-TT in group C were lower than those of the control group (p < 0.05). There was no difference in initial MMSE score among three patient groups; however, group A had a higher mean follow-up MMSE score than that of groups B and C (p < 0.05). CONCLUSIONS: Patients who underwent EVD of the affected hemisphere showed better results in terms of the PF-TT injury and cognitive outcome than patients who underwent EVD through the unaffected hemisphere or through both hemispheres.

Injury of ascending reticular activating system associated with delayed post-hypoxic leukoencephalopathy: a case report.

BACKGROUND: Delayed post-hypoxic leukoencephalopathy (DPHL) is a demyelinating syndrome characterized by neurological relapse after an initial recovery from hypoxic brain injury. We describe a patient with impaired consciousness following DPHL, concurrent with injury of the ascending reticular activating system (ARAS) shown using diffusion tensor tractography (DTT). CASE PRESENTATION: A 50-year-old male patient was in a drowsy mental state after exposure to carbon monoxide (CO) for about ten hours. About a day after the CO exposure, his mental state recovered to an alert condition. However, his consciousness deteriorated to drowsy 24 days after the exposure and worsened to a semi-coma state at 26 days after onset. When he started rehabilitation six weeks after the CO exposure, he had impaired consciousness, with a Glasgow Coma Scale score of 8 and a Coma Recovery Scale-Revised score of 8. On 6-week DTT, decreased neural connectivity of the upper ARAS between the intralaminar thalamic nucleus and the cerebral cortex was observed in both frontal cortices, basal forebrains, basal ganglia and thalami. The lower dorsal ARAS was not reconstructed on the right side, and was thin on the left side. The lower ventral ARAS was not reconstructed on either side. CONCLUSIONS: Using DTT, we demonstrated injury of the ARAS in a patient with impaired consciousness following DPHL. Our result suggests that injury of the ARAS is a plausible pathogenetic mechanism of impaired consciousness in patients with DPHL.

Akinetic mutism in a patient with mild traumatic brain injury: A diffusion tensor tractography study.

OBJECTIVES: Akinetic mutism (AM) is characterized by a complete absence of spontaneous behaviour and speech. We report on a patient with AM associated with injury of the prefronto-caudate tract and prefronto-thalamic tract following mild traumatic brain injury (TBI), diffusion tensor tractography (DTT). CASE PRESENTATION: A 20-year-old man suffered from TBI resulting from a pedestrian car accident. Following the TBI, he developed abulia (decreased activity and speech) that worsened over approximately a year. His typical features of AM that remained stable from one year until two years after the TBI are: he showed no spontaneous movement or speech and remained recumbent with no spontaneous activity. RESULTS: On one-month DTT, the neural connectivity of the caudate nucleus to the medial prefrontal cortex was low in both hemispheres, and this neural connectivity was lower on two-year DTT. The orbitofrontal-thalamic tract was thin in the left hemisphere on one-month DTT, whereas this tract became thinner in both hemispheres on two-year DTT. CONCLUSIONS: Using serial DTTs, injuries of the prefronto-caudate tract and orbitofrontal-thalamic tract and degeneration of these injured neural tracts concurrent with aggravation of abulia to AM were demonstrated in a patient with mild TBI. ABBREVIATIONS AM akinetic mutism; BA Brodmann areas; CN caudate nucleus; CST corticospinal tract; CRT corticoreticulospinal tract; DTT diffusion tensor tractography; FAC Functional Ambulation Category; PFC prefrontal cortex; MMSE Mini-Mental State Examination; ROI region of interest; TBI traumatic brain injury.

Degeneration of an injured spinothalamic tract in a patient with mild traumatic brain injury.

OBJECTIVES: This study reports on a patient who developed degeneration of an injured spinothalamic tract (STT) detected on diffusion tensor tractography (DTT) following mild traumatic brain injury (TBI). CASE DESCRIPTION: A 56-year-old female had suffered from head trauma resulting from a pedestrian car accident. The patient did not experience loss of consciousness or post-traumatic amnesia and the patient's Glasgow Coma Scale score was 15. She had begun to feel pain in her left hand and foot at ~ 7 days after onset. The characteristics and severity of pain were as follows: constant tingling and pricking sensation without allodynia or hyperalgesia (Visual Analogue Scale score: 3~4). No specific focal lesion was observed on brain and spine MRI and an electromyography study showed no evidence of peripheral nerve injury or radiculopathy. At 6 months after onset, the central pain in the left hand and foot became aggravated, with a Visual Analogue Scale score of 6. RESULTS: On 1-month DTT, partial tearing was observed in both STTs. In contrast, both partially torn STTs had become atrophy on 9-month DTT. CONCLUSIONS: This study recommends further studies conducted on the prognosis (regeneration or degeneration) of injured STTs and on the effect of change of an injured STT on central pain.

Injury of the inferior cerebellar peduncle in patients with mild traumatic brain injury: A diffusion tensor tractography study.

OBJECTIVES: No study on injury of the inferior cerebellar peduncle (ICP) in patients with mild traumatic brain injury (mTBI) has been reported. This study, using diffusion tensor tractography (DTT), attempted to demonstrate injury of the ICP in patients with mTBI. METHODS: Three patients with mTBI resulting from a car accident and 18 normal healthy control subjects were enrolled in this study. Diffusion tensor imaging data were acquired at 2 months (patient 1) and 3 months (patients 2 and 3) after onset and the ICP was reconstructed. The Balance Error Scoring System was used for evaluation of balance at the same time diffusion tensor imaging scanning was performed. RESULTS: The ICPs were discontinued at the upper portion of the vertical cerebellar branch and the transverse cerebellar branch (patient 1) and the proximal portion of the transverse cerebellar branch (patients 2 and 3) compared to the normal control subjects. Regarding DTT parameters, in the three patients, the fibre number of the ICPs was decreased by more than 2 SD compared with those of subjects in the control group. CONCLUSION: Evaluation of the ICP using DTT would be useful in patients with a balance problem after mTBI.

Injury of the corticobulbar tract in patients with dysarthria following cerebral infarct: diffusion tensor tractography study.

OBJECTIVES: Little is known about injury of the corticobulbar tract (CBT) in stroke patients. We attempted to investigate injury of the CBT in patients with dysarthria following cerebral infarct, using diffusion tensor tractography (DTT). METHODS: Eight patients with dysarthria following a corona radiata infarct and 12 control subjects were recruited for this study. Diffusion tensor imaging was performed at 14.3 days after onset and reconstruction of the CBT was performed using the probabilistic tractography method. Fractional anisotropy, mean diffusivity, and tract volume of the CBT were measured. RESULTS: Reconstructed CBTs in the affected hemisphere of the patient group were thinner than those of the unaffected hemisphere of the patient group and the control group. Regarding the DTT parameters of the CBTs, fractional anisotropy and tract volume were significantly lower in the affected hemisphere of the patient group than in the unaffected hemisphere of the patient group and the control group (p < 0.05). However, we did not observe any difference in the mean diffusivity value (p > 0.05). CONCLUSIONS: We demonstrated injury of the CBT in patients with dysarthria following cerebral infarct in the corona radiata using DTT. This result indicates the importance of CBT evaluation for dysarthria in patients with cerebral infarct. Therefore, we suggest that evaluations of the CBT using DTT would be useful for patients with dysarthria following cerebral infarct.

Change of the anterior corticospinal tract on the normal side of the brain in chronic stroke patients: Diffusion tensor imaging study.

We investigated change of the anterior corticospinal tract (CST) on the normal side of the brain in stroke patients, using diffusion tensor tractography (DTT). We recruited 32 stroke patients and 24 control subjects. Motricity Index and DTT for the whole and anterior CSTs were evaluated. According to findings, the fiber number of the anterior CST on the normal side of the brain of stroke patients was related to poor motor function of the affected extremities.

The cortical effect of chewing gum during hand movements: A functional MRI study.

Nine right-handed normal subjects were recruited for this study. We compared the cortical activation during execution of hand movements (right finger flexion-extension) with that during execution of hand movements while chewing gum (right side chewing). We found that execution of hand movements while chewing gum induced less activation in the contralateral SM1 than hand movements alone. Based on our findings, it appears chewing gum during execution of hand movements enhanced the efficiency of hand movements.

Injury of the dentato-rubro-thalamic tract in a patient with mild traumatic brain injury.

BACKGROUND: Several studies using diffusion tensor tractography (DTT) have demonstrated injury of the dentato-rubro-thalamic tract (DRTT) in various brain pathologies. However, no study on traumatic brain injury (TBI) has been reported. This case study attempted to demonstrate injury of the DRTT in a patient with mild TBI, using DTT. CASE DESCRIPTION: A 41-year-old female patient suffered from head trauma resulting from flexion-hyperextension injury by being hit from behind by a running car while stopped at an intersection. The patient lost consciousness and experienced post-traumatic amnesia for ∼1minute from the time of the car-accident. The patient's Glasgow Coma Scale score was 15. No specific lesion was observed on brain MRI. At 2 weeks after onset, the patient began to show resting and intentional tremor (more severe in the right upper and lower extremities) and ataxic gait. Her symptoms had been aggravated with the passage of time. On 1-month DTT, the left DRTT, which originated from the left dentate nucleus of the cerebellum, was thinner than the right DRTT. CONCLUSIONS: This study demonstrated injury of the DRTT in a patient with tremor and ataxia following mild TBI, using DTT. It is believed that analysis of the DRTT using DTT would be useful in elucidating the cause of post-traumatic abnormal movements.

Change of Neural Connectivity of the Red Nucleus in Patients with Striatocapsular Hemorrhage: A Diffusion Tensor Tractography Study.

The red nucleus (RN) is involved in motor control and it is known to have potential to compensate for injury of the corticospinal tract (CST). We investigated the change of connectivity of the RN (RNc) and its relation to motor function in patients with striatocapsular hemorrhage. Thirty-five chronic patients with striatocapsular hemorrhage were recruited. Motricity Index (MI), Modified Brunnstrom Classification (MBC), and Functional Ambulation Category (FAC) were measured for motor function. The probabilistic tractography method was used for evaluation of the RNc. Fractional anisotropy (FA), mean diffusivity (MD), and tract volume (TV) of the RNc were measured. FA and TV ratios of the RNc in patients with discontinuation of the affected CST were significantly higher than those of patients with preserved integrity of the CST in the affected hemisphere (p < 0.05). TV ratio of the RNc showed significant negative correlation with upper MI (weak correlation, r = -0.35), total MI (weak correlation, r = -0.34), and MBC (moderate correlation, r = -0.43), respectively (p < 0.05). We found that the neural structure of the RNc was relatively increased in the unaffected hemisphere compared with the affected hemisphere in patients with more severe injury of the CST.

Diffusion tensor tractography for the dorsal spinocerebellar tract in the human brain.

Using diffusion tensor tractography, we attempted to investigate and identify the anatomy of the dorsal spinocerebellar tract (SCT) in the human brain. We recruited 26 healthy volunteers. The dorsal SCT was determined by selection of fibers passing through three regions of interest. We found that all dorsal SCTs terminated in the ipsilateral cerebellum; in contrast, in 25 (48%) of 52 hemispheres, the dorsal SCT crossed into the contralateral hemisphere via the vermis of the anterior lobe.

Delayed gait disturbance due to injury of the corticoreticular pathway in a patient with mild traumatic brain injury.

BACKGROUND: Many studies have demonstrated neural injury in patients with mild traumatic brain injury, using diffusion tensor imaging (DTI). However, knowledge regarding injury of the corticoreticular pathway (CRP) is limited. This study reports on a patient with mild TBI who showed delayed gait disturbance due to injury of the CRP following head trauma, which was demonstrated by DTI. METHODS: A 14-year-old female patient suffered from an in-car accident: her head was hit with the backseat during hyperextension after flexion movement when her sedan was struck by another sedan from behind. She showed mild quadriparesis after onset. At 29 days after onset, she noted gait disturbance and aggravated quadriparesis with more severe weakness of the proximal joints. RESULTS: No abnormality was observed on brain MRI and electromyography study performed at 10 weeks after onset. Both CRPs were discontinued at the midbrain level on 10-week DTI. CONCLUSION: It appears that the proximal weakness of this patient was attributed to injury of both CRPs following head trauma. It is assumed that the mild weakness at the onset of head trauma was caused by the primary traumatic axonal injury and the aggravated weakness that started from 29 days might be ascribed to the secondary traumatic axonal injury.

Relative anterior safe area for invasive procedures in the human brain: diffusion tensor tractography.

OBJECTIVE: Many interventions, including surgery, procedures of shunt operation, or radiotherapy could result in neural injury of the brain. However, research to prevent or minimize injury of neural tracts has been overlooked. MATERIAL AND METHODS: We recruited 41 healthy subjects. Diffusion tensor images were acquired and five neural tracts were reconstructed (corticospinal tract, corticoreticular pathway, arcuate fasciculus, cingulum, and superior longitudinal fasciculus). We defined the safe area, which is an area free from any trajectory of five neural tracts: the medial boundary - the most lateral point free from any trajectory of five neural tracts, the posterior boundary - the most anterior point free from any trajectory of five neural tracts. RESULTS: Medial boundaries of the safe area in the cortex, centrum semiovale, corona radiata, and internal capsule were located at an average of 0 mm, 12.28 mm, 12.43 mm, and 10.34 mm laterally from the midline, respectively, and the posterior boundaries were located at an average of 1.30 mm, 4.26 mm, 7.05 mm, and 5.74 mm from the ACL, respectively. In addition, we found that the common safe areas for all four axial levels were located at 13.44 mm (medial boundary) and 9.35 mm (posterior boundary). CONCLUSION: We identified a relatively safe area for the performance of invasive procedures in the anterior portion of the human brain.

Deterioration of pre-existing hemiparesis due to injury of the ipsilateral anterior corticospinal tract.

BACKGROUND: The anterior corticospinal tract (CST) has been suggested as one of the ipsilateral motor pathways, which contribute to motor recovery following stroke. In this study, we report on a patient who showed deterioration of pre-existing hemiparesis due to an injury of the ipsilateral anterior CST following a pontine infarct, as evaluated by diffusion tensor tractography (DTT). CASE PRESENTATION: A 55-year-old male patient showed quadriparesis after the onset of an infarct in the right pontine basis. He had history of an infarct in the left middle cerebral artery territory 7 years ago. Consequently, he showed right hemiparesis before onset of the right pontine infarct. Following this, his right hemiparesis deteriorated whereas his left hemiparesis newly developed. The DTTs for whole CST of the right hemisphere in the patient and both hemispheres in control subjects descended through the known CST pathway. By contrast, the DTT for the left whole CST of the patient showed a complete injury finding. The DTTs for the anterior CST of control subjects passed through the known pathway of the CST from cerebral cortex to medulla and terminated in the anterior funiculus of the upper cervical cord. However, the DTT for right anterior CST in the patient showed discontinuation below the right pontine infarct. CONCLUSION: It appeared that the deterioration of the pre-existing right hemiparesis was ascribed to an injury of the right anterior CST due to the right pontine infarct.

Anatomical location of the medial lemniscus and spinothalamic tract at the pons in the human brain: a diffusion tensor tractography study.

Using diffusion tensor tractography, we investigated the anatomical location of medial lemniscus (ML) and spinothalamic tract (STT) at pons. We recruited 47 healthy volunteers. Evaluation of the anatomical location of ML and STT was performed using the highest probabilistic location at the upper, middle, and lower pons. According to findings, MLs were located around the middle to medial one-third, between midline and lateral boundary of pons in the pontine tegmentum and STTs were located posterolaterally to ML.

Diffusion tensor tractography of the corticobulbar tract in a dysphagic patient with progressive supranuclear palsy: A case report.

RATIONALE: This paper reports the changes over time in the corticobulbar tract (CBT) analyzed using diffusion tensor tractography (DTT) in a dysphagic patient with progressive supranuclear palsy (PSP). PATIENT CONCERNS: A 53-year-old man initially presented with dysarthria, gait disturbance, and bradykinesia, and approximately 1-year later, downward gaze paralysis appeared. Initially, there was no dysphagia; however, approximately 2 years after visiting the hospital, symptoms of dysphagia, including difficulty swallowing pills, aspiration, and oral movement impairments appeared. The symptoms gradually progressed, and finally, mouth opening was severely damaged to the extent that it was difficult to orally feed. INTERVENTIONS: We performed diffusion tensor imaging 3 times; at 3-month, 20-month, and 41-month from onset. OUTCOMES: On 3-month DTT, the left CBT was well reconstructed, whereas the right CBT showed partial tearing. In the 20-month DTT, both CBTs became thinner compared to the 3-month DTT. On 41-month DTT, both CBTs became much thinner than after 3-month and 20-month DTT. LESSONS: We observed the degree of CBT injury over time in a dysphagic patient with PSP. These results suggest that the analysis of CBT using DTT is helpful in predicting the degree of dysphagia and prognosis in patients with PSP.

Diagnostic sensitivity of traumatic axonal injury of the spinothalamic tract in patients with mild traumatic brain injury.

ABSTRACT: Diffusion tensor tractography (DTT) can detect traumatic axonal injury (TAI) in patients whose conventional brain magnetic resonance imaging results are negative. This study investigated the diagnostic sensitivity of TAI of the spinothalamic tract (STT) in patients with a mild traumatic brain injury (TBI) suffering from central pain symptoms, using DTT.Thirty-five patients with central pain following mild TBI and 30 healthy control subjects were recruited for this study. After DTT-based reconstruction of the STT, we analyzed the STT in terms of configuration (narrowing and/or tearing) and the DTT parameters (fractional anisotropy and tract volume).Thirty-three (94.3%) patients had at least 1 DTT parameter value at 1 standard deviation below the control group value, and 20 (57.1%) patients had values at 2 standard deviations, below the control group value. All 35 patients showed STT abnormalities (tearing, narrowing, or both) on DTT.A high diagnostic sensitivity of TAI of the STT in patients with mild TBI was achieved. However, the small number of subjects who visited the university hospital and the limitations of DTT should be considered when generalizing the results of this study.