Biomedical subjects
Publications and source records attributed to Alan Diamond.
Increasingly, more centers perform deep brain stimulation (DBS) for the treatment of movement disorders; however, the majority of publications focus on treatment outcomes at tertiary care centers. We retrospectively evaluated nine consecutive patients who were implanted with DBS, initially programmed at other centers, and eventually referred to a community practice for follow up.
Globus pallidus deep brain stimulation (GPi-DBS) is a useful alternative in the treatment of dystonia. Patients selected for GPi-DBS were prospectively rated with the Unified Dystonia Rating Scale (UDRS). Also, "blinded" videotape assessments were performed. Eleven patients were identified. Compared with pre-DBS scores, there were improvements in mean total UDRS score (15.3%) and in the following subscores: neck (18.18%), trunk (32.9%), arm (17.9%), and leg (19.9%). One patient developed a skin infection and erosion requiring surgical debridement. GPi-DBS is a safe and effective treatment for generalized dystonia in patients who remained impaired, despite optimal medical therapy.
We report on a 30-year-old man with Tourette's syndrome (TS) and medication-refractory epilepsy whose tics improved after implantation of a vagal nerve stimulator (VNS). To verify the patient's observation, we performed a blinded video assessment using the modified Rush video-based tic rating scale. The patient underwent two separate video recordings (VNS on and VNS off). A rater, blinded to patient's VNS status, evaluated the videos with the modified Rush video-based tic rating scale. There were improvements in total tic score and motor and phonic tic frequency. If verified by controlled clinical trials, this observation may provide insights into the pathophysiology of tics and may lead to a novel therapy for patients with severe TS.
Parkinson's disease is a progressive neurological disorder characterized by tremor, bradykinesia, rigidity, gait and postural instability and a variety of nonmotor symptoms. While these and other motor signs typically improve with levodopa, the so-called axial signs, such as dysarthria, dysphagia, postural instability and freezing, and most nonmotor signs, such as depression, cognitive decline and dysautonomia, usually do not respond satisfactorily to levodopa. Furthermore, the use of levodopa may be limited by the development of motor fluctuations, dyskinesias and other adverse effects. This manuscript reviews the medical management of advanced Parkinson's disease, focusing on the treatment of motor fluctuations and dyskinesias and of nonmotor and nonlevodopa responsive symptoms.
BACKGROUND: The purpose of this study was to explore whether there are white matter (WM) abnormalities in children with attention-deficit/hyperactivity disorder (ADHD) using diffusion tensor imaging. Based upon the literature, we predicted decreased fractional anisotropy (FA) findings in the frontal and cerebellar regions. METHODS: Eighteen patients with ADHD and 15 age- and gender-matched healthy volunteers received DTI assessments. Fractional anisotropy maps of WM were compared between groups with a voxelwise analysis after intersubject registration to Talairach space. RESULTS: Children with ADHD had decreased FA in areas that have been implicated in the pathophysiology of ADHD: right premotor, right striatal, right cerebral peduncle, left middle cerebellar peduncle, left cerebellum, and left parieto-occipital areas. CONCLUSIONS: These preliminary data support the hypothesis that alterations in brain WM integrity in frontal and cerebellar regions occur in ADHD. The pattern of decreased FA might implicate the corticopontocerebellar circuit in the pathophysiology of ADHD.
OBJECTIVE: To investigate abnormalities in the structural integrity of brain white matter as suggested by diffusion tensor imaging in adolescents with early-onset schizophrenia (onset of psychosis by age 18). METHOD: Twenty-six patients with schizophrenia and 34 age- and gender-matched healthy volunteers received diffusion tensor imaging and structural magnetic resonance imaging examinations. Fractional anisotropy maps were compared between groups in the white matter using a voxelwise analysis after intersubject registration to Talairach space. RESULTS: Compared with healthy volunteers, patients demonstrated lower fractional anisotropy values in the left anterior cingulate region in close proximity to the caudate nucleus (95% confidence interval of schizophrenic-healthy: -66 to -20). Using regression analysis, the rate of change in fractional anisotropy differed significantly between groups in this region across the age span examined (10-20 years), after adjusting for group differences in premorbid intellectual capacity and parental socioeconomic status. There were no areas of significantly higher fractional anisotropy in patients compared with healthy volunteers. CONCLUSIONS: These data suggest that early-onset schizophrenia is associated with a disruption in the structural integrity of white matter tracts in the anterior cingulate region. These structural abnormalities may contribute to the deficits in motivation, attention, memory, and higher executive functions in adolescents with schizophrenia.
There is considerable evidence that receptive language processing depends, at least in part, on cortical tissue in the temporal lobe. Few studies, however, have investigated the neural basis of phonemic discrimination while controlling for non-linguistic and attentional components. In this study nine healthy volunteers discriminated sets of phonemes and tones interspersed by rest periods in a block design paradigm while undergoing fMRI. A comparison of phonemic discrimination with tone discrimination revealed pure left lateralized superior and middle temporal gyrus activations. A comparison of phonemic discrimination with the rest blocks resulted in areas of activations encompassing the language and non-language components of the task. Our findings are consistent with prior reports demonstrating the involvement of the superior and middle temporal gyrus in phonemic discrimination and stronger left temporal lobe activation during speech compared to non-speech sounds. This study also demonstrates the advantage of tone discrimination control blocks as opposed to conventional rest periods to isolate the pure language component of phonemic discrimination.
OBJECTIVES/HYPOTHESIS: Hemophilic pseudotumors are rare clinical entities in otolaryngology. An unusual case of a pediatric hemophilic pseudotumor of the paranasal sinus in a previously undiagnosed hemophiliac is presented. STUDY DESIGN: Case report. METHODS: A 6-month-old, otherwise healthy boy was admitted for evaluation of a rapidly expanding left-sided cheek mass. The patient's initial presentation, imaging workup, and intraoperative and postoperative courses are discussed. RESULTS: Imaging workup revealed a large, heterogeneous, dense lesion in the patient's left-side maxillary sinus with distortion of the orbital floor and hard palate. Because of the concern for an aggressive malignancy, a biopsy was performed. After a Caldwell-Luc approach, a large amount of greenish fluid leaked from an otherwise empty maxillary sinus. The patient continued to bleed from his intraoral incision postoperatively and required two packed erythrocyte transfusions. Subsequent hematological testing led to a diagnosis of severe hemophilia type A with factor VIII levels less than 1% of normal. After treatment with recombinant coagulation factors hemostasis was achieved, and the patient clinically improved. CONCLUSION: The study presents the first report of a pediatric hemophilic pseudotumor in the paranasal sinuses leading to a diagnosis of hemophilia. It is a rare entity characterized by a cycle of repeated hemorrhage with subsequent encapsulation of the coagulum leading to pressure-induced distortion of adjacent bone. In the correct clinical setting, hemophilic pseudotumor should be considered in the differential diagnosis of a rapidly expanding mass in children.
OBJECTIVE: To present an unusual case of recurrent facial palsy resulting from acute leukemic infiltration of the parotid gland. STUDY DESIGN: Case report. METHODS: An 11-year-old boy who had been treated for acute lymphoblastic leukemia (ALL) from 3 to 6 years of age presented with intermittent left facial nerve palsy with concurrent ipsilateral parotid fullness. The initial findings at diagnosis and workup are presented, and the disease progression and resolution with therapy are documented. RESULTS: The patient had been off therapy when this finding developed. A workup for central and viral etiologies for the facial palsy was unrevealing. Biopsy of the parotid gland demonstrated a lymphoblastic leukemic infiltrate. The patient was placed on a chemotherapy protocol for relapsed leukemia, resulting in complete resolution of the facial palsy. CONCLUSION: Isolated facial nerve dysfunction, albeit rare, has been documented as a sign of central nervous system involvement in leukemia, but until now this presentation has not been described in the setting of leukemic relapse presenting with acute infiltration of the parotid gland.
BACKGROUND AND PURPOSE: The main clinical indication for functional MR imaging (fMRI) has been to preoperatively map the cortex. Motor paradigms to activate the cortex are simple and robust; however, language tasks show greater variability and difficulty. The aim of this study was to develop a language task with an adequate control task to engage the areas of the posterior temporal lobe responsible for sentence comprehension. METHODS: We performed a cloze paradigm requiring silent reading of a visually presented sentence-completion task based on semantic meaning versus a letter-scanning epoch requiring the completion of nonlinguistic strings or a rest period. Before this task was clinically used in two patients epilepsy and cavernous angioma, its feasibility and accuracy were tested in 14 healthy right-handed participants. RESULTS: Results showed significant activation of the posterior temporal cortex, including a broad area across the posterior left temporal cortex extending into the inferior parietal lobule. When the sentence completion-minus-letter string task was compared with the sentence completion-minus-rest task, increased activation was present in the posterior temporal lobe. CONCLUSION: Decreased significant activation during the sentence completion-minus-rest contrast may be attributed to increased noise from intersubject variability in the rest period. Our results suggest that this task elucidates areas important to reading comprehension in the posterior and inferior temporal regions that verbal fluency and auditory discrimination tasks do not. Data from two cases are summarized to exemplify the input of this task for neurosurgery.