Some two-microphone noise reduction techniques that work in the frequency domain exploit coherence function between two noisy signals. They have shown good results when noise signals on two sensors are uncorrelated, b...Some two-microphone noise reduction techniques that work in the frequency domain exploit coherence function between two noisy signals. They have shown good results when noise signals on two sensors are uncorrelated, but their per-formance decreases with correlated noises. Coherence based methods can be improved when the cross power spectral density (CPSD) of correlated noise signals is available. In this paper, we propose a new method for estimation of the CPSD of the noise, which is based on the minimum tracking technique. Despite the fact that the proposed estimator does not need to implement a voice activity detector (VAD), its performance is comparable to a CPSD estimator that uses an ideal VAD.展开更多
A 24-year-old male was transferred to the emergency department while being in the state of quadriplegia with a history of performing Parkour sport, which is also called double front flip. Neurological examination reve...A 24-year-old male was transferred to the emergency department while being in the state of quadriplegia with a history of performing Parkour sport, which is also called double front flip. Neurological examination revealed that the patient＇s muscle power was 0/5 at all extremities. The patient did not show any sense of light touch or pain in his extremities. In radiological studies, cervical spine X-ray and CT scan images showed C4-C5 subluxation with bilateral locked facets and spinal cord injury. The results of this very rare case study revealed that exercising Parkour sport without taking into account safety standards could result in irreversible injuries to the cervical spinal cord with fatal outcome.展开更多
Background:Retinitis pigmentosa(RP)is one of the most severe hereditary retinal disorders with a worldwide prevalence reaching 1 in every 3000-5000 people and a total of almost one million affected individuals.RP is h...Background:Retinitis pigmentosa(RP)is one of the most severe hereditary retinal disorders with a worldwide prevalence reaching 1 in every 3000-5000 people and a total of almost one million affected individuals.RP is heterogeneous in its clinical presentations but typically presents as progressive visual dysfunction,including nyctalopia in adolescence,restricted peripheral vision(tunnel vision)in young adults,and loss of central vision at an advanced age.Case description:Herein,we want to report a case of RP who presented with gradual worsening of vision and headache,and further evaluation revealed a concomitant non-functional pituitary macroadenoma.Ophthalmologic evaluation revealed a little chance for him to regain his vision,so the patient refused to undergo endoscopic surgical resection.However,he is still under clinic-radiologic follow-up,to be evaluated for progression in tumor size and obstructive hydrocephalus.Conclusion:Presenting with similar symptoms of tunnel vision,the simultaneous occurrence of these two diseases in a patient may delay the diagnosis of the latter,leading to its progression.展开更多
In regards to the case presentation entitled: "Spinal cord injury in Parkour sport (free running): a rare case report;1 by Nima Derakhshan et al, I received some critic letters, asking to amend the distinctions b...In regards to the case presentation entitled: "Spinal cord injury in Parkour sport (free running): a rare case report;1 by Nima Derakhshan et al, I received some critic letters, asking to amend the distinctions between the two entities, Parkour and Freerunning. Due to media misrepresentations, Parkour and Freerunning are often confused, and are sometimes used synonymously.However, although there are factors that make these disciplines similar, there are also important factors that make them distinct.展开更多
Background:Since the introduction of neuro-endoscopy by Walter Dandy and his colleagues in the early 1920's,several efforts has been made to improve this tool for treatment of hydrocephalus,brain tumors,arachnoid ...Background:Since the introduction of neuro-endoscopy by Walter Dandy and his colleagues in the early 1920's,several efforts has been made to improve this tool for treatment of hydrocephalus,brain tumors,arachnoid cysts,etc and has largely substituted craniotomy procedures.Several complications such as CSF leakage,intraventicular hemorrhage,infectious complications and transient and permanent psycho-neurologic deficits have been reported for neuro-endoscopic procedures in children.Here in,two cases of transient murism following neuroendoscopy in children were reported,with special focus on pathophysiology,management and clinical course.Knowledge about the possible complications of a procedures,empowers the pediatric neurosurgeon with the ability to avoid them and also to successfully handle them once they take place.Case presentation:We report two patients who underwent neuro-endoscopy,first for treatment of arachnoid cyst via cystoventriculostomy and second for endoscopic third ventriculostomy(E-rV) to treat hydrocephalus.Both children developed apathy and mutism following the procedure.However,this condition was transient and both children improved after a course of 5-6 days with conservative management.Conclusions:Mutism following neuro-endoscopic procedures in children may result from excessive traction on paraventricular white matter and disruption of fronto-subcortical circuits.It can be avoided with less intra-procedural dilation of venricles and less traction on white matter tracts with choosing a more accurate trajectory.However,this condition is transient and spontaneous resolution wil ensue in several days wth conservative management.展开更多
基金Project supported by the Iran Telecommunications Research Center (ITRC)
文摘Some two-microphone noise reduction techniques that work in the frequency domain exploit coherence function between two noisy signals. They have shown good results when noise signals on two sensors are uncorrelated, but their per-formance decreases with correlated noises. Coherence based methods can be improved when the cross power spectral density (CPSD) of correlated noise signals is available. In this paper, we propose a new method for estimation of the CPSD of the noise, which is based on the minimum tracking technique. Despite the fact that the proposed estimator does not need to implement a voice activity detector (VAD), its performance is comparable to a CPSD estimator that uses an ideal VAD.
文摘A 24-year-old male was transferred to the emergency department while being in the state of quadriplegia with a history of performing Parkour sport, which is also called double front flip. Neurological examination revealed that the patient＇s muscle power was 0/5 at all extremities. The patient did not show any sense of light touch or pain in his extremities. In radiological studies, cervical spine X-ray and CT scan images showed C4-C5 subluxation with bilateral locked facets and spinal cord injury. The results of this very rare case study revealed that exercising Parkour sport without taking into account safety standards could result in irreversible injuries to the cervical spinal cord with fatal outcome.
文摘Background:Retinitis pigmentosa(RP)is one of the most severe hereditary retinal disorders with a worldwide prevalence reaching 1 in every 3000-5000 people and a total of almost one million affected individuals.RP is heterogeneous in its clinical presentations but typically presents as progressive visual dysfunction,including nyctalopia in adolescence,restricted peripheral vision(tunnel vision)in young adults,and loss of central vision at an advanced age.Case description:Herein,we want to report a case of RP who presented with gradual worsening of vision and headache,and further evaluation revealed a concomitant non-functional pituitary macroadenoma.Ophthalmologic evaluation revealed a little chance for him to regain his vision,so the patient refused to undergo endoscopic surgical resection.However,he is still under clinic-radiologic follow-up,to be evaluated for progression in tumor size and obstructive hydrocephalus.Conclusion:Presenting with similar symptoms of tunnel vision,the simultaneous occurrence of these two diseases in a patient may delay the diagnosis of the latter,leading to its progression.
文摘In regards to the case presentation entitled: "Spinal cord injury in Parkour sport (free running): a rare case report;1 by Nima Derakhshan et al, I received some critic letters, asking to amend the distinctions between the two entities, Parkour and Freerunning. Due to media misrepresentations, Parkour and Freerunning are often confused, and are sometimes used synonymously.However, although there are factors that make these disciplines similar, there are also important factors that make them distinct.
文摘Background:Since the introduction of neuro-endoscopy by Walter Dandy and his colleagues in the early 1920's,several efforts has been made to improve this tool for treatment of hydrocephalus,brain tumors,arachnoid cysts,etc and has largely substituted craniotomy procedures.Several complications such as CSF leakage,intraventicular hemorrhage,infectious complications and transient and permanent psycho-neurologic deficits have been reported for neuro-endoscopic procedures in children.Here in,two cases of transient murism following neuroendoscopy in children were reported,with special focus on pathophysiology,management and clinical course.Knowledge about the possible complications of a procedures,empowers the pediatric neurosurgeon with the ability to avoid them and also to successfully handle them once they take place.Case presentation:We report two patients who underwent neuro-endoscopy,first for treatment of arachnoid cyst via cystoventriculostomy and second for endoscopic third ventriculostomy(E-rV) to treat hydrocephalus.Both children developed apathy and mutism following the procedure.However,this condition was transient and both children improved after a course of 5-6 days with conservative management.Conclusions:Mutism following neuro-endoscopic procedures in children may result from excessive traction on paraventricular white matter and disruption of fronto-subcortical circuits.It can be avoided with less intra-procedural dilation of venricles and less traction on white matter tracts with choosing a more accurate trajectory.However,this condition is transient and spontaneous resolution wil ensue in several days wth conservative management.
