Common Focal Neuropathies in the Hospitalized Patient.

Neuropathies are a common problem encountered by neurologist in the hospitalized setting. Nerve injury may occur secondary to compression, stretch, and direct trauma, among other causes. Common focal neuropathies include the ulnar, median, and radial nerve in the upper extremities and sciatic, peroneal, and femoral nerve in the lower extremities. Surgical and obstetric risk factors are especially important considerations in evaluation of patients with focal neuropathies. Treatment is either conservative therapy or surgery depending on the mechanism of injury and extent of recovery.

The Neural Correlates of Spatial Disorientation in Head Direction Cells.

While the brain has evolved robust mechanisms to counter spatial disorientation, their neural underpinnings remain unknown. To explore these underpinnings, we monitored the activity of anterodorsal thalamic head direction (HD) cells in rats while they underwent unidirectional or bidirectional rotation at different speeds and under different conditions (light vs dark, freely-moving vs head-fixed). Under conditions that promoted disorientation, HD cells did not become quiescent but continued to fire, although their firing was no longer direction specific. Peak firing rates, burst frequency, and directionality all decreased linearly with rotation speed, consistent with previous experiments where rats were inverted or climbed walls/ceilings in zero gravity. However, access to visual landmarks spared the stability of preferred firing directions (PFDs), indicating that visual landmarks provide a stabilizing signal to the HD system while vestibular input likely maintains direction-specific firing. In addition, we found evidence that the HD system underestimated angular velocity at the beginning of head-fixed rotations, consistent with the finding that humans often underestimate rotations. When head-fixed rotations in the dark were terminated HD cells fired in bursts that matched the frequency of rotation. This postrotational bursting shared several striking similarities with postrotational "nystagmus" in the vestibulo-ocular system, consistent with the interpretation that the HD system receives input from a vestibular velocity storage mechanism that works to reduce spatial disorientation following rotation. Thus, the brain overcomes spatial disorientation through multisensory integration of different motor-sensory inputs.

Embedded Palliative Care for Amyotrophic Lateral Sclerosis: A Pilot Program and Lessons Learned.

Background and Objectives: Palliative care (PC) is recommended for people with amyotrophic lateral sclerosis (ALS), but there is scant literature about how to best provide this care. We describe the structure and impact of a pilot program that integrates longitudinal, interdisciplinary PC into the care of patients with ALS. Methods: Observational cohort study of patients with ALS referred to outpatient PC and seen for at least 3 PC visits October 2017-July 2020. Results: Fifty-five patients met the inclusion criteria. Three-quarters (74.5%) were Caucasian, and 78.2% spoke English. Patients were referred for advance care planning (58.2%), support for patient/family (52.7%), and symptoms other than pain (50.9%). Patients had a mean of 5 scheduled PC visits, the majority occurred by video. A PC physician, nurse, social worker, and chaplain addressed pain (for 43.6% of patients), nonpain symptoms (94.5%), psychosocial distress (78.2%), spiritual concerns (29.1%), care planning (96.4%), and supported family caregivers (96.4%). With PC, the rate of completion of advance directives increased from 16.4% to 36.4% (p = 0.001) and Physician Orders for Life-Sustaining Treatment forms from 10.9% to 63.6% (p < 0.001). Of the 27 patients who died, 77.8% used hospice, typically for more than 30 days. Eleven patients obtained aid-in-dying prescriptions, and 8 took these medications, accounting for 29.6% of the deaths. Discussion: Integrating longitudinal, interdisciplinary PC into the care of patients with ALS is feasible, addresses needs in multiple domains, and is associated with increased rates of advance care planning. Controlled studies are needed to further elucidate the impact of PC on patients with ALS, their families, and clinicians.

Stimulation of the posterior cord predicts successful infraclavicular block.

Infraclavicular (IC) block is often performed by localizing one cord within the brachial plexus sheath and placing all the local anesthetic solution at that location. We hypothesized that posterior cord stimulation would be associated with a greater likelihood of IC block success. We enrolled 369 patients scheduled for surgery to the lower arm or hand in a prospective, nonrandomized observational trial. All underwent IC blocks using a standard technique, and the cord stimulated immediately before drug injection was recorded. Motor and sensory functioning were evaluated 15 min after injection. Compared with stimulation of either the lateral or medial cord, stimulation of the posterior cord was associated with rapid onset of motor block in significantly more nerves, as well as a decreased likelihood of block failure (motor and sensory block inadequate to perform surgery). Failure rates were 5.8% for posterior cord, 28.3% for lateral (P < 0.05), and 15.4% for medial (P < 0.05). The differences were highly significant when adjusted for multiple possible confounders, such as gender, body mass index, location of the incision, and level of training of the individual performing the block (P < 0.001, lateral versus posterior; P = 0.003, medial versus posterior). A low failure rate was also predicted by stimulation of more than one cord simultaneously (P < 0.05). We conclude that injection after locating the posterior cord or multiple cords predicts successful IC block.

The Role of Electrodiagnostic Testing, Imaging, and Muscle Biopsy in the Investigation of Muscle Disease.

PURPOSE OF REVIEW: This article reviews the roles of electrodiagnostic testing, imaging studies (MRI and ultrasound), and muscle biopsy in evaluating patients for possible muscle diseases. RECENT FINDINGS: In addition to electrodiagnostic testing and muscle biopsy, muscle imaging is increasingly being used in the evaluation of patients with suspected muscle disease. MRI and ultrasound can help identify patterns of muscle involvement that may narrow the differential diagnosis and guide further testing. In addition, imaging can identify potential targets for muscle biopsy and can help evaluate for and exclude certain conditions that may mimic muscle disease. SUMMARY: This article provides a comprehensive overview of various testing modalities used in the evaluation of patients with suspected muscle disease, including electrodiagnostic studies, muscle imaging, and biopsy. In combination with a thorough history and clinical examination, these modalities can help narrow the differential diagnosis or, in certain cases, can confirm a specific etiology of muscle disease.

Infant botulism: review and clinical update.

Botulism is a rare neuromuscular condition, and multiple clinical forms are recognized. Infant botulism was first identified in the 1970s, and it typically occurs in infants younger than 1 year of age who ingest Clostridium botulinum spores. A specific treatment for infant botulism, intravenous botulism immunoglobulin (BIG-IV or BabyBIG®), was developed in 2003, and this treatment has substantially decreased both morbidity and hospital costs associated with this illness. This article will review the pathogenesis of infant botulism as well as the epidemiology, clinical manifestations, diagnosis, and treatment of this condition.

A quality assurance initiative targeting radiation exposure to neuroscience patients in the intensive care unit.

BACKGROUND: Patients admitted to an intensive care unit (ICU) with a primary neurologic disorder often receive multiple radiation-based diagnostic studies of the head and neck. Although radiation exposure puts them at risk of intracranial and neck tumors, the amount of radiation received is largely unknown. METHODS: We sought to accurately collect cumulative radiation exposure data from radiation-based studies in a retrospective cohort of patients admitted to the neuroscience ICU (NICU) at a single institution. Radiation doses of studies were converted to estimated effective doses in mSv via literature-published formulas. To impact ordering practices, we piloted an educational initiative on patient radiation exposure to a cohort of physicians caring for patients with a diagnosis of acute subarachnoid hemorrhage. Patients were randomized to have radiation exposure data posted at the bedside for physician viewing. RESULTS: We identified 641 patients from July 2010 to March 2011 who had received at least 1 computed tomography-based study of the head. Patients received on average 18.4 mSv of radiation from head and neck imaging. Patients with subarachnoid hemorrhage received the highest average levels of radiation exposure (37.1 mSv). Attributable risk of carcinogenesis was estimated to be low. A pilot educational initiative did not reduce the total estimated effective dose per patient. CONCLUSIONS: Accurate reporting of estimated effective doses for NICU patients is feasible and can be provided to ordering physicians to assist with clinical decision making and potentially lower exposure risk. Further strategies are needed to reduce unnecessary radiation exposure at the physician ordering level.

A volumetric MRI study of limbic, associative and sensorimotor striatal subregions in schizophrenia.

INTRODUCTION: Cognitive and emotional functioning is mediated by frontal-subcortical feedback loops. The striatum, a component of this circuitry, thus is a possible neural substrate of schizophrenia. Striatum volume, however, is believed to be differentially influenced by neuroleptic treatment due to an anterior-posterior D2 receptor density gradient. We thus rigorously parcellated it into subregions in order to assess whether neuroleptic effect on group differences is regionally specific. METHODS: 29 chronic, male, schizophrenia patients and 28 male, normal controls (NCs), group-matched for handedness, age, and parental SES, underwent structural brain imaging on a 1.5 Tesla GE system. We manually measured the volume, normalized for intracranial contents, of the striatum parcellated into anatomic subregions and their corresponding limbic, associative and sensorimotor functional subregions and performed clinical correlations. RESULTS: First, we found a localized bilateral enlargement of the posterior putamen in medicated chronic schizophrenia. Second, we showed associative striatal subregion volumes correlated with executive function in schizophrenia subjects and, to a lesser extent, in NCs. Third, we showed associative striatal subregions inversely correlated with negative symptoms but conversely, the ventral/limbic striatum did not correlate with positive or negative clinical symptoms. DISCUSSION: Our novel parcellation strategy, based on rigorous delineation of the ventral striatum, allowed for the demonstration of localized volumetric differences between schizophrenia and NCs. Furthermore, by parcellating the striatum into functional subregions we demonstrated significant positive correlations between the volume of the associative striatum and executive functioning in schizophrenia, adding further support to the importance of its role in the pathophysiology of schizophrenia.

Fractional anisotropy and radial diffusivity: diffusion measures of white matter abnormalities in the anterior limb of the internal capsule in schizophrenia.

INTRODUCTION: Higher cognitive functioning is mediated by frontal-subcortical cognitive and limbic feedback sub-loops. The thalamo-cortical projection through the anterior limb of the internal capsule (ALIC) serves as the final step in these feedback sub-loops. We evaluated abnormalities in the ALIC fiber tract in schizophrenia using both structural MRI and diffusion tensor imaging (DTI). METHODS: 20 chronic schizophrenia patients and 22 male, normal controls group matched for handedness, age, and parental SES, underwent structural and DTI brain imaging on a 1.5 Tesla GE system. We manually measured ALIC volume normalized for intracranial contents (ICC) using structural brain images and then registered these high resolution structural brain scan derived ALIC label maps to DTI space allowing for the measurement in the ALIC of diffusion indices including, fractional anisotropy (FA) mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). RESULTS: We found in the ALIC of chronic schizophrenia subjects, compared with normal controls, bilaterally lower FA and bilaterally higher RD, but no differences in AD, MD, or relative volume. Cognitive correlations in schizophrenia patients showed, in particular, that higher left ALIC FA correlated positively with better verbal and nonverbal declarative/episodic memory performance. DISCUSSION: Using a novel approach to assess both diffusion and volume measures in the ALIC in schizophrenia, we found abnormalities in measures of diffusion, but not volume, supporting their importance as sensitive indices of abnormalities in white matter fiber bundles in schizophrenia. Our findings also support the role of ALIC white matter tract FA abnormalities in declarative/episodic memory in schizophrenia.