Pseudobulbar affect: an under-recognized and under-treated neurological disorder

INTRODUCTION

Pseudobulbar affect (PBA) is a neurologic syndrome of emotional affect disinhibition, characterized by uncontrollable, exaggerated, and often inappropriate emotional outbursts, which may cause severe distress, embarrassment, and social dysfunction. However, the US prevalence of PBA remains unknown.

METHODS

An online survey was conducted primarily to estimate the US prevalence of PBA in patients with the six most commonly associated conditions: Alzheimer's disease, amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, stroke, and traumatic brain injury. Invitations to participate were randomly sent online to adults (aged ≥ 18 years) registered in the Harris Poll Online Panel who were patients or belonged to a household with a patient diagnosed with one of the six conditions (identified through previous screening by Harris Interactive). Participants were screened for PBA using the Pathological Laughing and Crying Scale (PLACS) and the Center for Neurologic Study-Lability Scale (CNS-LS). PBA estimates were made using a cut-off score of ≥ 13 on the PLACS and two different cut-off thresholds on the CNS-LS, a lower one of ≥ 13 and a more rigorous one of ≥ 21. Existing US prevalence data for the six underlying conditions were used to estimate US prevalence of PBA.

RESULTS

Of 38,000 individuals invited to participate, 8876 responded (23%) and 2318 (26%) completed the questionnaire. Mean prevalence of PBA across all six conditions was 10.1%, 9.4%, and 37.5% with the PLACS ≥ 13, CNS-LS ≥ 21, and CNS-LS ≥ 13 thresholds, respectively. Using disease population estimates from government agencies and professional organizations, the estimated US population with PBA ranged from 1.8 to 7.1 million. Among patients who discussed their laughing and/or crying episodes with a physician, 41% were diagnosed, and about half received a medication for their episodes.

CONCLUSIONS

The overall prevalence of PBA was estimated to be about 10% across these commonly associated underlying neurological conditions and appears to be under-recognized.

Cyanobacteria and BMAA exposure from desert dust: a possible link to sporadic ALS among Gulf War veterans

Veterans of the 1990-1991 Gulf War have been reported to have an increased incidence of amyotrophic lateral sclerosis (ALS) compared to personnel who were not deployed. An excess of ALS cases was diagnosed in Gulf War veterans younger than 45 years of age. Increased ALS among Gulf War veterans appears to be an outbreak time-limited to the decade following the Gulf War. Seeking to identify biologically plausible environmental exposures, we have focused on inhalation of cyanobacteria and cyanotoxins carried by dust in the Gulf region, particularly Qatar. Cyanobacterial crusts and mats are widespread in the deserts of Qatar, occupying up to 56% of the available area in some microhabitats. These cyanobacterial crusts, which help bind the desert sands, are dormant throughout most of the year, but during brief spring rains actively photosynthesize. When disturbed by vehicular traffic or other military activities, the dried crusts and mats can produce significant dust. Using HPLC/FD, an amino acid analyzer, UPLC/MS, and triple quadrupole LC/MS/MS we find that the dried crusts and mats contain neurotoxic cyanobacterial toxins, including beta-N-methylamino-L-alanine (BMAA) and 2,4 diaminobutyric acid (DAB). If dust containing cyanobacteria is inhaled, significant exposure to BMAA and other cyanotoxins may occur. We suggest that inhalation of BMAA, DAB, and other aerosolized cyanotoxins may constitute a significant risk factor for the development of ALS and other neurodegenerative diseases.

BMAA neurotoxicity in Drosophila

We report the establishment of an in vivo model using the fruit fly Drosophila melanogaster to investigate the toxic effects of L-BMAA. We found that dietary intake of BMAA reduced the lifespan as well as the neurological functions of flies. Furthermore, we have developed an HPLC method to reliably detect both free and protein-bound BMAA in fly tissue extracts.

Beyond Guam: the cyanobacteria/BMAA hypothesis of the cause of ALS and other neurodegenerative diseases

Excitement about neurogenetics in the last two decades has diverted attention from environmental causes of sporadic ALS. Fifty years ago endemic foci of ALS with a frequency one hundred times that in the rest of the world attracted attention since they offered the possibility of finding the cause for non-endemic ALS throughout the world. Research on Guam suggested that ALS, Parkinson's disease and dementia (the ALS/PDC complex) was due to a neurotoxic non-protein amino acid, beta-methylamino-L-alanine (BMAA), in the seeds of the cycad Cycas micronesica. Recent discoveries that found that BMAA is produced by symbiotic cyanobacteria within specialized roots of the cycads; that the concentration of protein-bound BMAA is up to a hundred-fold greater than free BMAA in the seeds and flour; that various animals forage on the seeds (flying foxes, pigs, deer), leading to biomagnification up the food chain in Guam; and that protein-bound BMAA occurs in the brains of Guamanians dying of ALS/PDC (average concentration 627 microg/g, 5 mM) but not in control brains have rekindled interest in BMAA as a possible trigger for Guamanian ALS/PDC. Perhaps most intriguing is the finding that BMAA is present in brain tissues of North American patients who had died of Alzheimer's disease (average concentration 95 microg/g, 0.8mM); this suggests a possible etiological role for BMAA in non-Guamanian neurodegenerative diseases. Cyanobacteria are ubiquitous throughout the world, so it is possible that all humans are exposed to low amounts of cyanobacterial BMAA, that protein-bound BMAA in human brains is a reservoir for chronic neurotoxicity, and that cyanobacterial BMAA is a major cause of progressive neurodegenerative diseases including ALS worldwide. Though Montine et al., using different HPLC method and assay techniques from those used by Cox and colleagues, were unable to reproduce the findings of Murch et al., Mash and colleagues using the original techniques of Murch et al. have recently confirmed the presence of protein-bound BMAA in the brains of North American patients dying with ALS and Alzheimer's disease (concentrations >100 microg/g) but not in the brains of non-neurological controls or Huntington's disease. We hypothesize that individuals who develop neurodegenerations may have a genetic susceptibility because of inability to prevent BMAA accumulation in brain proteins and that the particular pattern of neurodegeneration that develops depends on the polygenic background of the individual.

Possible therapy for ALS based on the cyanobacteria/BMAA hypothesis

Although the cyanobacteria/BMAA hypothesis of the cause of ALS and other age-related neurodegenerative diseases remains to be proven, it is not too early to ask whether treatment would be possible if the hypothesis were correct. This paper reviews the possible ways that chronic BMAA neurotoxicity could be prevented or treated.

Cyanobacterial neurotoxin BMAA in ALS and Alzheimer's disease

OBJECTIVE

The aim of this study was to screen for and quantify the neurotoxic amino acid beta-N-methylamino-L-alanine (BMAA) in a cohort of autopsy specimens taken from Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and non-neurological controls. BMAA is produced by cyanobacteria found in a variety of freshwater, marine, and terrestrial habitats. The possibility of geographically broad human exposure to BMAA had been suggested by the discovery of BMAA in brain tissues of Chamorro patients with ALS/Parkinsonism dementia complex from Guam and more recently in AD patients from North America. These observations warranted an independent study of possible BMAA exposures outside of the Guam ecosystem.

METHODS

Postmortem brain specimens were taken from neuropathologically confirmed cases of 13 ALS, 12 AD, 8 HD patients, and 12 age-matched non-neurological controls. BMAA was quantified using a validated fluorescent HPLC method previously used to detect BMAA in patients from Guam. Tandem mass spectrometric (MS) analysis was carried out to confirm the identification of BMAA in neurological specimens.

RESULTS

We detected and quantified BMAA in neuroproteins from postmortem brain tissue of patients from the United States who died with sporadic AD and ALS but not HD. Incidental detections observed in two out of the 24 regions were analyzed from the controls. The concentrations of BMAA were below what had been reported previously in Chamarro ALS/ Parkinsonism dementia complex patients, but demonstrated a twofold range across disease and regional brain area comparisons. The presence of BMAA in these patients was confirmed by triple quadrupole liquid chromatography/mass spectrometry/mass spectrometry.

CONCLUSIONS

The occurrence of BMAA in North American ALS and AD patients suggests the possibility of a gene/environment interaction, with BMAA triggering neurodegeneration in vulnerable individuals.

A Phase I safety study of hyperbaric oxygen therapy for amyotrophic lateral sclerosis

BACKGROUND

Vascular endothelial growth factor and mitochondrial abnormalities have been described in ALS and its animal models. We have reported that hyperbaric oxygen (HBO) treatment delayed the onset of weakness in the wobbler mouse.

OBJECTIVE

To perform a Phase I safety study of HBO in patients with ALS.

METHODS

Five patients with ALS were treated for 60min with 100% oxygen at 2 atmospheres pressure daily for five days a week for four weeks. The patients reported any deterioration in their condition after each treatment, and their neurological condition was measured serially during the four weeks of the treatment, and for four further weeks.

RESULTS

Four patients reported decreased fatigue, while one patient dropped out at three weeks because of increased fatigue. Maximum isometric voluntary contraction (MVIC) of all muscle groups except right hand grip improved significantly by up to 97%. Most improvement occurred during the four weeks after treatment. It is possible that the improvement in muscle strength was a placebo or a learning effect, though no such effects have been detected in prior therapeutic trials in ALS using MVIC. No change was detected in other measures of neuromuscular function.

CONCLUSIONS

A longer duration, placebo controlled trial in a larger number of patients is needed to determine the safety and efficacy of HBO. Until that is completed, it is not recommended that ALS patients should be treated with HBO.

Outcomes research in amyotrophic lateral sclerosis: lessons learned from the amyotrophic lateral sclerosis clinical assessment, research, and education database

OBJECTIVE

To examine the care of patients with ALS following the publication of the standardized recommendations for the management of patients with amyotrophic lateral sclerosis (ALS) published in 1999 by the American Academy of Neurology.

METHODS

Specific aspects of ALS patient management have been evaluated serially using a national Amyotrophic Lateral Sclerosis Clinical Assessment, Research, and Education (ALS CARE) database to encourage compliance with these recommendations and to assure continuing quality improvement.

RESULTS

The most recent analysis of 5,600 patients shows interesting epidemiological observations and treatment trends. Proper management of many ALS symptoms has increased substantially since the first publication of the guidelines, and awareness of pseudobulbar affect has increased. Other recommendations are underutilized: Only 9% undergo percutaneous endoscopic gastrostomy, although this procedure was recommended in 22% of patients; and noninvasive positive pressure ventilation was used by only 21% of patients despite being associated with improved 5-year survival rates.

INTERPRETATION

This observational database has been a useful tool in monitoring compliance with the standard of care for patients with ALS and may have resulted in greater adherence to guidelines.

Detecting neurobehavioral changes in amyotrophic lateral sclerosis

Cognitive impairment in patients with amyotrophic lateral sclerosis (ALS) is well documented, but behavioral abnormalities are not well defined. The Frontal Systems Behavior Scale (FrSBe) was used to assess changes in apathy, disinhibition, and executive dysfunction in 45 patients with ALS. Results suggest a high incidence of behavioral change, most notably in apathy associated with the onset of the disease and independent of mood. Apathy and verbal fluency were correlated, lending further support to the hypothesis that an underlying continuum exists between ALS and frontotemporal dementia (FTD), which is characterized predominantly by behavioral disturbance. The FrsBe is useful for detecting behavioral change and abnormalities in patients with ALS.

Premorbid personality characteristics of patients with ALS

Experienced neurologists caring for patients with amyotrophic lateral sclerosis (ALS) have commented that these patients commonly exhibit similar personality features. Previous research studies on the premorbid personality characteristics of ALS patients have however not clearly substantiated this observation. In the present study, caregivers of newly diagnosed ALS patients provided ratings of patients' premorbid personality traits, and these ratings were compared with those of caregivers of patients newly diagnosed with other chronic, progressive diseases. Results indicated that ALS patients were rated as significantly lower than the other medical patients in the Openness trait on the NEO-Personality Inventory. This finding is discussed in relation to past research findings, prevailing clinical characterizations of ALS patients, and current research on cognitive and behavioral changes in ALS.

Mitochondrial involvement in amyotrophic lateral sclerosis: trigger or target?

Despite numerous reports demonstrating mitochondrial abnormalities associated with amyotrophic lateral sclerosis (ALS), the role of mitochondrial dysfunction in the disease onset and progression remains unknown. The intrinsic mitochondrial apoptotic program is activated in the central nervous system of mouse models of ALS harboring mutant superoxide dismutase 1 protein. This is associated with the release of cytochrome-c from the mitochondrial intermembrane space and mitochondrial swelling. However, it is unclear if the observed mitochondrial changes are caused by the decreasing cellular viability or if these changes precede and actually trigger apoptosis. This article discusses the current evidence for mitochondrial involvement in familial and sporadic ALS and concludes that mitochondria is likely to be both a trigger and a target in ALS and that their demise is a critical step in the motor neuron death.

Quantitative measurement of blood-brain barrier permeability using perfusion-CT in extra-axial brain tumors

Non-invasive assessment of vascular permeability is of main importance in the diagnosis, treatment and follow-up of intracranial tumors. Perfusion-CT is one of the imaging options available, which affords quantitative assessment of cerebral blood volume and blood-brain barrier permeability. Herein we report two cases of extra-axial tumors studied with perfusion-CT. Comparison with perfusion-MRI was available in one case. High permeability values, as measured by perfusion-CT, reflected the absence of blood-brain barrier in these extra-axial tumors.

Artifact simulating subarachnoid and intraventricular hemorrhage on single-shot, fast spin-echo fluid-attenuated inversion recovery images caused by head movement: A trap for the unwary

BACKGROUND AND PURPOSE

Single-shot, fast spin-echo, fluid attenuated inversion recovery (SS-FSE-FLAIR) images are frequently used to detect disease in the brain and subarachnoid space in confused or uncooperative patients who may move during the examination. In some of these patients, high signal intensity areas are seen on good-quality images in the subarachnoid space and ventricular system in locations not associated with high CSF flow. These artifacts may simulate hemorrhage or leptomeningeal disease. The purpose of this article was to determine the cause of these artifacts, describe ways to recognize them, and find methods to reduce or eliminate them.

METHODS

Healthy volunteers were studied on 6 occasions with conventional multisection FSE-FLAIR images and SS-FSE-FLAIR images while at rest and while nodding and rotating their heads at different speeds. In addition, SS-FSE-FLAIR images with different section widths of the initial inverting pulse and a non-section-selective initial inversion pulse were performed with the subjects moving their heads in the same way. The scans of 30 successive patients with acute neurologic syndromes who had been studied with SS-FSE-FLAIR sequences were reviewed for evidence of high signal intensity in the CSF in regions not associated with high CSF flow.

RESULTS

Each of the volunteers showed areas of increased signal intensity in CSF at sites apart from those associated with rapid pulsatile CSF flow on SS-FSE-FLAIR images acquired during head motion. The images were otherwise virtually free of motion artifact. The use of a wider initial inversion pulse section and a non-section-selected initial inversion pulse reduced the extent of these artifacts. Nineteen of the 30 patients showed areas of high signal intensity in the CSF in regions not associated with highly pulsatile CSF flow. Six of these patients had negative lumbar punctures for blood and xanthochromia and normal CSF protein levels.

CONCLUSION

High signal intensity artifacts may be seen in CSF as a result of head movement on otherwise artifact-free images when imaging uncooperative patients with SS-FSE-FLAIR sequences. These artifacts have a different mechanism and distribution from those caused by CSF pulsation and may simulate subarachnoid and intraventricular hemorrhage. Artifact recognition is aided by signs of patient motion during the examination. The artifacts can be reduced by use of increased section width and non-section-selective initial inversion pulses. Recognition of these artifacts is important, because the circumstances in which the SS-FSE-FLAIR sequence is used and the particular properties of the sequence may conspire to produce a trap for the unwary.

Diagnosis and Treatment of Chronic Immune-mediated Neuropathies

The chronic autoimmune neuropathies are a diverse group of disorders, whose diagnosis and classification is based on the clinical presentations and results of ancillary tests. In chronic inflammatory demyelinating polyneuropathy, controlled therapeutic trials demonstrated efficacy for intravenous gamma-globulins, corticosteroids, and plasmaphereis. In multifocal motor neuropathy, intravenous gamma-globulins have been shown to be effective. In the other immune-mediated neuropathies, there are no reported controlled therapeutic trials, but efficacy has been reported for some treatments in non-controlled trials on case studies. Choice of therapy in individual cases is based on reported efficacy, as well as severity, progression, coexisting illness, predisposition to developing complications, and potential drug interactions.