Life goes on: Spatial heterogeneity promotes biodiversity in an urbanized coastal marine ecosystem.

Both human populations and marine biodiversity are concentrated along coastlines, with growing conservation interest in how these ecosystems can survive intense anthropogenic impacts. Tropical urban centres provide valuable research opportunities because these megacities are often adjacent to mega-diverse coral reef systems. The Pearl River Delta is a prime exemplar, as it encompasses one of the most densely populated and impacted regions in the world and is located just northwest of the Coral Triangle. However, the spatial and taxonomic complexity of this biodiversity, most of which is small, cryptic in habitat and poorly known, make comparative analyses challenging. We deployed standardized settlement structures at seven sites differing in the intensity of human impacts and used COI metabarcoding to characterize benthic biodiversity, with a focus on metazoans. We found a total of 7184 OTUs, with an average of 665 OTUs per sampling unit; these numbers exceed those observed in many previous studies using comparable methods, despite the location of our study in an urbanized environment. Beta diversity was also high, with 52% of the OTUs found at just one site. As expected, we found that the sites close to point sources of pollution had substantially lower diversity (44% less) relative to sites bathed in less polluted oceanic waters. However, the polluted sites contributed substantially to the total animal diversity of the region, with 25% of all OTUs occurring only within polluted sites. Further analysis of Arthropoda, Annelida and Mollusca showed that phylogenetic clustering within a site was common, suggesting that environmental filtering reduced biodiversity to a subset of lineages present within the region, a pattern that was most pronounced in polluted sites and for the Arthropoda. The water quality gradients surrounding the PRD highlight the unique role of in situ studies for understanding the impacts of complex urbanization pressures on biodiversity.

Subtropical thermal variation supports persistence of corals but limits productivity of coral reefs.

Concomitant to the decline of tropical corals caused by increasing global sea temperatures is the potential removal of barriers to species range expansions into subtropical and temperate habitats. In these habitats, species must tolerate lower annual mean temperature, wider annual temperature ranges and lower minimum temperatures. To understand ecophysiological traits that will impact geographical range boundaries, we monitored populations of five coral species within a marginal habitat and used a year of in situ measures to model thermal performance of vital host, symbiont and holobiont physiology. Metabolic responses to temperature revealed two acclimatization strategies: peak productivity occurring at annual midpoint temperatures (4-6°C lower than tropical counterparts), or at annual maxima. Modelled relationships between temperature and P:R were compared to a year of daily subtropical sea temperatures and revealed that the relatively short time spent at any one temperature, limited optimal performance of all strategies to approximately half the days of the year. Thus, while subtropical corals can adjust their physiology to persist through seasonal lows, seasonal variation seems to be the key factor limiting coral productivity. This constraint on rapid reef accretion within subtropical environments provides insight into the global distribution of future coral reefs and their ecosystem services.

Long-term adherence to apomorphine infusion in patients with Parkinson disease: a 10-year observational study.

BACKGROUND: Patients with Parkinson disease (PD) commonly experience motor fluctuations and dyskinesias in response to oral dopaminergic medications. Affected patients may benefit from device-assisted therapy, such as medication infusion or deep brain stimulation surgery. This is the first Australian study of the long-term adherence to apomorphine infusion (AI) in patients with PD. AIMS: To assess the adherence to AI in patients with PD in a single centre over a 10-year period and to find the reasons for discontinuation in patients who discontinued AI. METHODS: This is an observational study of patients with PD treated with AI between 2004 and 2014. Outcome measures included changes in motor function and quality of life following AI, change in dose of other dopaminergic medications following AI, duration of infusion, adverse effects, reasons for cessation of AI and subsequent treatment after cessation. RESULTS: Mean duration of AI was 21.65 months. No patient achieved apomorphine monotherapy, and the mean reduction in the levodopa-equivalent dose of other dopaminergic medications after AI was 22.7%. The benefit of AI on motor function and quality of life was rated as 'much improved' or 'better' in 83% of patients. The most common reasons for discontinuation of AI were adverse effects and inadequate motor benefit. Most patients who discontinued AI were subsequently treated with another device-assisted therapy. CONCLUSION: AI is an effective therapy for severe motor response complications in PD, especially in the short and medium term. However, many patients cannot be maintained on AI in the longer term.

Facial bradykinesia.

The aim of this paper is to summarise the main clinical and pathophysiological features of facial bradykinesia in Parkinson's disease (PD) and in atypical parkinsonism. Clinical observation suggests that reduced spontaneous and emotional facial expressions are features of facial bradykinesia in PD and atypical parkinsonism. In atypical parkinsonism, facial bradykinesia is complicated by additional dystonic features. Experimental studies evaluating spontaneous and emotional facial movements demonstrate that PD is characterised by a reduction in spontaneous blinking and emotional facial expression. In PD, neurophysiological studies show that voluntary orofacial movements are smaller in amplitude and slower in velocity. In contrast, movements of the upper face (eg, voluntary blinking) are normal in terms of velocity and amplitude but impaired in terms of switching between the closing and opening phases. In progressive supranuclear palsy (PSP), voluntary blinking is not only characterised by a severely impaired switching between the closing and opening phases of voluntary blinking, but is also slow in comparison with PD. In conclusion, in PD, facial bradykinesia reflects abnormalities of spontaneous, emotional and voluntary facial movements. In PSP, spontaneous and voluntary facial movements are abnormal but experimental studies on emotional facial movements are lacking. Data on facial bradykinesia in other atypical parkinsonism diseases, including multiple system atrophy and corticobasal degeneration, are limited. In PD, facial bradykinesia is primarily mediated by basal ganglia dysfunction whereas in PSP, facial bradykinesia is a consequence of a widespread degeneration involving the basal ganglia, cortical and brainstem structures.

Frontal lobe motor syndromes.

The motor phenomena accompanying frontal lobe disease are diverse, reflecting the various roles the frontal lobes play in the organization of motor control. The principal frontal motor areas, the primary motor cortex, the premotor cortex, and the supplementary motor area, have different but interrelated functions in motor control. The principal efferent pathway of the primary motor cortex is the corticospinal tract which conducts fine motor control. Damage to the primary motor cortex and the corticospinal tract results in paralysis and loss of skilled, particularly distal, motor function. Lesions of the premotor cortex interfere with the preparation for the execution of movements and coordinating sequences of limb movement. Mediated through cortico-reticulospinal pathways, the premotor cortex adjusts axial and limb muscle activities. The fine motor skills of the corticospinal tract are superimposed upon these stabilizing movements. Supplementary motor area lesions interrupt self-initiated movements, release alien limb behaviors, and result in grasping. Paralysis, primitive reflexes, and frontal gait disorders are readily observed on examination, but difficulties initiating and sequencing movements are more subtle signs of perturbed higher motor control and require special examination procedures. Prefrontal motor syndromes include motor behaviors that only become apparent when the subject performs spontaneous or self-directed activities, unconstrained by instructions from the examiner. Clinical observation also reveals a slowness to respond to instruction with long delays before initiating action (inertia), but once underway they may be unable to stop (perseveration). Patients sit motionless without spontaneous movement or interest in their surrounds (apathy), yet exhibit distractibility, diverting attention to an incidental peripheral stimulus or an object with which they may then fiddle (environmental dependency and utilization behavior). Little spontaneous speech is initiated (abulia) but echolalia may be stimulated by the examiner's conversation. Restlessness, distractibility, perseveration, and environmentally dependent utilization behaviors coexist with apathy, inertia, and abulia. Mutism and akinesia may alternate with stereotypies and agitation in catatonia. These paradoxical combinations are of considerable diagnostic significance in recognizing frontal lobe motor syndromes.

Upper limb tremor.

Tremor is a common clinical problem in middle-aged and older patients, and Parkinson disease (PD) is one of the commonest causes. Careful history-taking and physical examination is usually sufficient for diagnosis of PD; extensive investigation is generally not required. Treatment of PD should be individualised, taking into account the patient's age, lifestyle, severity of motor symptoms, level of disability, comorbidities, expectations of treatment and PD subtype (eg, akinetic rigid or tremor dominant). In PD, optimal medical therapy often involves a combination of dopaminergic medications, aiming for doses that provide adequate symptom relief without adverse effects such as dyskinesias and impulse-control disorders. Continuous dopaminergic stimulation and deep brain stimulation should be considered for patients with PD whose motor symptoms cannot be adequately controlled with oral medication, especially those aged less than 70 years.

Milestones in myoclonus.

This review examines some of the advances in understanding myoclonus over the last 25 years. The classification of myoclonus into cortical, brainstem, and spinal forms has been consolidated, each with distinctive clinical characteristics and physiological mechanisms. New genetic causes of myoclonus have been identified, and the molecular basis of several of these conditions has been discovered. It is increasingly apparent that disease of the cerebellum is particularly important in the genesis of cortical reflex myoclonus. However, the precise mechanism and origin of myoclonus in many situations remain uncertain. Effective treatment of myoclonus remains limited, and the challenge lies ahead to develop more therapeutic options.

Limb amputations in fixed dystonia: a form of body integrity identity disorder?

Fixed dystonia is a disabling disorder mainly affecting young women who develop fixed abnormal limb postures and pain after apparently minor peripheral injury. There is continued debate regarding its pathophysiology and management. We report 5 cases of fixed dystonia in patients who sought amputation of the affected limb. We place these cases in the context of previous reports of patients with healthy limbs and patients with chronic regional pain syndrome who have sought amputation. Our cases, combined with recent data regarding disorders of mental rotation in patients with fixed dystonia, as well as previous data regarding body integrity identity disorder and amputations sought by patients with chronic regional pain syndrome, raise the possibility that patients with fixed dystonia might have a deficit in body schema that predisposes them to developing fixed dystonia and drives some to seek amputation. The outcome of amputation in fixed dystonia is invariably unfavorable.

Response to Comment on Trophic strategy and bleaching resistance in reef-building corals.

Recently, we published a novel method used to assess the trophic niches of different coral species and demonstrated that their nutrition varied considerably, with some species highly dependent on their photosynthetic algal symbionts and others able to feed on plankton to meet energetic requirements. Adjustments to the use of this tool are necessary when it is applied to other scientific questions and symbiotic organisms. We respond to a comment highlighting a risk of bias in the methods, discuss suggested adjustments, and propose further refinements to improve method robustness.

The effect of temperature on physiology, toxicity and toxin content of the benthic dinoflagellate Coolia malayensis from a seasonal tropical region.

Coolia malayensis is one of the commonly found benthic dinoflagellates in Hong Kong which can produce biotoxins and threaten the early life stages of marine invertebrates. Seawater temperature has been recognized as one of the primary environmental factors that affect the formation of harmful algal blooms. The present study evaluated the responses of C. malayensis, including growth, toxicity and toxin content (putative analogues of okadaic acid and azaspiracids), after exposure to a range of seven different temperatures (i.e., 16°C, 18°C, 20°C, 22°C, 24°C, 26°C, and 28°C). The highest algal density and specific growth rate were recorded at 24°C. Significantly higher Fv/Fm (maximum quantum yield of PSII) and total phaeo-pigment values were observed in the exponential growth phase at 28°C. The toxicity of the algal extract, which was assessed by the lethality rate of Artemia larvae, increased with temperature. The highest toxin content was detected at the second highest temperature treatment, i.e., 26°C. Overall, temperature had significant effects on the physiological activities and toxicity of C. malayensis. This study has raised attention to the potentially increasing risks posed by toxic benthic dinoflagellates during heat waves in coastal waters.

Trophic strategy and bleaching resistance in reef-building corals.

Ocean warming increases the incidence of coral bleaching, which reduces or eliminates the nutrition corals receive from their algal symbionts, often resulting in widespread mortality. In contrast to extensive knowledge on the thermal tolerance of coral-associated symbionts, the role of the coral host in bleaching patterns across species is poorly understood. Here, we applied a Bayesian analysis of carbon and nitrogen stable isotope data to determine the trophic niche overlap between corals and their symbionts and propose benchmark values that define autotrophy, heterotrophy, and mixotrophy. The amount of overlap between coral and symbiont niche was negatively correlated with polyp size and bleaching resistance. Our results indicated that as oceans warm, autotrophic corals lose their competitive advantage and thus are the first to disappear from coral reefs.

Cranial movement disorders: clinical features, pathophysiology, differential diagnosis and treatment.

Cranial movement disorders are a common neurological problem. These disorders can be limited to the cranial muscles alone or manifest as part of a more generalized movement disorder. Cranial movement disorders can originate from the highest (motor cortex) to the lowest (cranial nerve and muscle) levels of the motor system. Owing to the lack of diagnostic tests and biomarkers for these disorders, their differential diagnosis can be difficult even for the experienced neurologist. Advances have, however, been made in the identification and treatment of these conditions, and most can be managed effectively with appropriate knowledge of the diagnostic signs and effective treatments. Here, we review the clinical features, pathophysiologies and therapies of the main movement disorders that affect the face, jaw, tongue and palate.

Dancing Dorsal Quadrilaterals: A Novel Peripherally Induced Movement Disorder.

Importance: Recognized peripherally induced movement disorders include the painful legs moving toes syndrome, postamputation dyskinesias, and belly dancer dyskinesias. Objective: To introduce and characterize the dancing dorsal quadrilaterals, a novel peripherally induced movement disorder that predominantly affects dorsal quadrilateral muscles (trapezius and rhomboids) after upper spine instrumentation. Design, Setting, and Participants: Between 1990 and 2015, a total of 4 patients who developed abnormal movements of the dorsal quadrilateral muscles after upper spine instrumentation were referred to movement disorders clinics at 3 academic medical centers in the United States, Canada, and Argentina. A prospective and retrospective analysis of the clinical and electrophysiologic characteristics of their abnormal movements is presented in this brief report. Data were analyzed between July 2015 and January 2018. Exposures: Extensive upper spine instrumentation complicated with misalignment and prolonged postsurgical neuropathic pain. Main Outcomes and Measures: Video documentation of clinical and electrophysiologic characteristics of dancing dorsal quadrilaterals. Results: Four patients with upper spine disease (2 women and 2 men, ranging in age from early 30s to early 70s) required extensive surgical manipulation and instrumentation that was complicated by misalignment, prolonged dorsal neuropathic pain, and unusual abnormal movements. These movements consisted of semirhythmic, repetitive writhing, and jerky movements of the scapular region with distinctive rotatory motions. They are referred to as the dancing dorsal quadrilaterals because they predominantly affected the bilateral trapezius and rhomboids (dorsal quadrilateral muscles) but could spread to adjacent muscles, and they are similar in appearance and possibly pathogenesis to "belly dancer" dyskinetic movements. The movements of the dancing dorsal quadrilaterals occur when upright but not when lying down or during voluntary muscle activation. Sensory stimulation also diminishes the movements. Long-duration bursts of normal motor unit potentials with normal recruitment pattern were evidenced. Conclusions and Relevance: The dancing dorsal quadrilaterals syndrome represents a further example of a peripherally induced movement disorder characterized by neuropathic pain preceding a regional movement disorder following soft-tissue or nerve injury.

Investigation of an unusual, high-frequency jaw tremor with coherence analysis.

Normal physiological tremor of the jaw has a frequency of 6 to 8 Hz. A patient is described with jaw tremor at frequencies of 12 Hz during jaw movement and 15 Hz when the jaw was relaxed. The 15 Hz tremor was driven by synchronous, bilateral bursts of activity in the temporalis and masseter muscles, which alternated with digastric bursts. Coherence analysis indicated the tremor was highly correlated with both opening and closing muscle activity, and that the opening and closing muscles were about 180 degrees out of phase. The existence of two tremors with different, nonphysiological peak frequencies and the influence of attention, relaxation, and movement in switching from one tremor frequency to the other, suggest that more than one generator may be operating.

The distinctive movement disorder of ovarian teratoma-associated encephalitis.

The movement disorder observed in four cases of ovarian teratoma associated encephalitis is described. The illness began with neuropsychiatric symptoms and was followed by prolonged unresponsiveness, respiratory failure, and autonomic instability. The movement disorder consisted of semirhythmic repetitive bulbar and limb movements and persisted during prolonged periods of unresponsiveness, diminishing as awareness returned. The characteristics of the movement disorder differed from recognized dyskinesias. It is suggested that interruption of forebrain corticostriatal inputs by anti-N-methyl-D-aspartate (NMDA) receptor antibodies removes tonic inhibition of brainstem pattern generators releasing primitive patterns of bulbar and limb movement. Recognition of the distinctive movements should prompt a search for an ovarian teratoma since the condition is responsive to tumor resection and immunomodulation.

Cardio-embolic cerebellar stroke secondary to mitral valve chordae rupture as a delayed complication of a high-voltage electrical injury.

A 41-year-old farmer sustained a high-voltage electrical injury resulting in confusion, electrical burns and paroxysmal atrial fibrillation which spontaneously reverted to sinus rhythm after a few hours. Two weeks later he presented with a sudden onset of headache, unsteadiness, horizontal oscillopsia and paraesthesia in the right side of his face. Examination revealed nystagmus to the right, right-sided limb ataxia and a tendency to veer toward the right when walking. An MRI of the brain demonstrated an acute infarct of the right cerebellar hemisphere in the territory of the right posterior inferior cerebellar artery. A transesophageal echocardiogram showed a ruptured mitral valve chordae. This is the first report of a cardio-embolic stroke secondary to mitral valve chordae rupture as a delayed complication of high-voltage electrical injury. Although many mechanisms of direct cerebral electrical injury have been speculated, a cardio-embolic origin should not be overlooked as a cause of stroke secondary to high-voltage electrical injury.

Brainstem lesions and gait.

The brainstem contains virtually all of the important structures involved in experimental models of locomotion, encompassing control of upright posture, balance, and stepping. The physiologic basis for these functions is intricately related. Studies of the effects of lesions and disease on these functions in humans are limited to clinical observation and hampered by the anatomic complexity of closely spaced structures and lack of selectivity of lesions. Accordingly, any description of the clinical effects of brainstem lesions on gait and posture is imprecise because weakness and ataxia either predominate over or obscure any selective disturbance of the control of locomotion that may be correlated with the findings in experimental models. New and more sophisticated methods of brain imaging along with physiologic studies of balance and stepping may provide advances in human gait disorders, especially in relation to the brainstem control of locomotion.

The effect of cutaneous input on intracortical inhibition in focal task-specific dystonia.

In normal subjects short interval intracortical inhibition (SICI) is topographically modulated by cutaneous input, which may be important for focusing muscle activation during tasks. In patients with writer's cramp, a task-specific focal dystonia characterized by inappropriate and excessive muscle activation of the upper limb during certain motor tasks, intracortical inhibition is reduced at rest and lacks the normal topographically-specific modulation during motor tasks. In the present study we investigated whether cutaneous input modulated SICI in a group of patients with writer's cramp and a control group of subjects. Electromyographic recordings were made from the right first dorsal interosseous (FDI), abductor pollicis brevis (APB), and abductor digiti minimi (ADM) muscles. Brief electrical stimuli were applied to either digit II or digit V with ring electrodes. SICI was investigated using a paired transcranial magnetic stimulation paradigm employing interstimulus intervals of 1-15 ms. Cutaneous input from both digit II and digit V modulated motor evoked potentials and SICI in a topographically-specific manner in control subjects. In contrast, cutaneous input failed to modulate motor evoked potentials or SICI in the focal hand dystonia patients. These results provide further evidence of abnormal sensorimotor integration in focal hand dystonia.

Influence of combined afferent stimulation and task-specific training following stroke: a pilot randomized controlled trial.

BACKGROUND: Reorganization of the human motor cortex can be induced by specific patterns of peripheral afferent stimulation. The potential for afferent stimulation to facilitate the functional recovery associated with conventional rehabilitative techniques has not previously been investigated. OBJECTIVE: The authors sought to determine whether combining appropriate afferent stimulation with task-specific training resulted in greater improvements than training alone in patients with impaired upper limb function in the subacute phase following stroke. METHOD: Twenty patients with hemiparesis due to stroke were allocated randomly to either a stimulation or control group. All received 9 sessions of task-specific physiotherapy training over 3 weeks. Prior to each training session, associative electrical stimulation of the motor point of 2 hand muscles was given in the stimulation group, whereas the control group received sham stimulation. Changes in dexterity were assessed using a grip-lift task, and standard measures of upper-limb function were made before and following the intervention. Corticospinal excitability was examined using transcranial magnetic stimulation. RESULTS: Both groups showed comparable improvements in functional measures of upper-limb function. Of the 20 patients, only 14 could perform the grip-lift task, which is an objective measure of dexterity. Patients in the stimulation group exhibited significantly greater improvements in this task than the control group. There was no significant change in corticospinal excitability in either group. CONCLUSION: This pilot study provides preliminary data suggesting that targeted afferent stimulation may facilitate the response to conventional rehabilitation in patients with hemiparesis due to stroke, but these results need to be confirmed in a larger scale study.

Early investigation and treatment of obstructive sleep apnoea after acute stroke.

Obstructive sleep apnoea (OSA) is an independent risk factor for hypertension, which is a major cause of stroke. The prevalence and associations of OSA in a cohort of stroke patients were studied. The safety and tolerability of early treatment with nasal continuous airways pressure (nCPAP) was also assessed. Consecutive subjects admitted with acute stroke were assessed clinically, radiologically and with scales assessing prior OSA risk, dysphagia and disability. Sleep studies were performed within the first few days of admission using a portable diagnostic system. Twenty-nine of 55 (53%) subjects had evidence of OSA, using an apnoea-hypopnoea index (AHI) of 10 or greater. The AHI was significantly associated with an index of prior OSA symptoms, but not with history of hypertension, degree of dysphagia, or type and severity of stroke. Use of a portable diagnostic system for detecting OSA in the acute stroke setting was well tolerated. OSA is common after acute stroke and exceeds rates seen in control populations of similar age (53% vs. 11%). Early treatment with nCPAP was effective and well tolerated.