Longitudinal clinical decline and baseline predictors in progressive supranuclear palsy

INTRODUCTION

Progressive supranuclear palsy (PSP) is associated with several clinical variants defined based on ocular motor dysfunction, postural instability, akinesia, and cognitive dysfunction, although little is known about how these features progress over time. We aimed to assess the evolution of these core clinical features across variants and assess baseline clinical and neuroimaging predictors of progression.

METHODS

Ninety-three PSP patients were recruited by the Neurodegenerative Research Group, Mayo Clinic, and underwent two visits 1-year apart, with baseline MRI and [18F]flortaucipir PET. We compared baseline and annualized rates of clinical change on the PSP Rating Scale (total, ocular motor, gait/midline scores) and Montreal Cognitive Assessment, across PSP-Richardson's, PSP-Cortical and PSP-Subcortical variants and assessed relationships between rates of change and baseline regional imaging.

RESULTS

Ocular motor scores differed across groups at baseline and follow-up, with lowest scores observed in PSP-subcortical, but no differences were observed in rate of change across groups. PSP Rating Scale total and gait/midline scores differed across groups at follow-up and in rates of change, with PSP-subcortical showing the least impairment and slowest progression. Greatest cognitive impairment was observed in PSP-Cortical. Sample size estimates for treatment trials differed across PSP variants. Greater baseline flortaucipir uptake, but not volume, of midbrain and motor cortex correlated with faster rates of clinical decline.

CONCLUSION

The PSP Rating Scale and its subscores might be useful markers for the prognostic stratification of PSP variants. Flortaucipir imaging at baseline may help predict rate of decline.

Patterned Stimulation of the Chrimson Opsin in Glutamatergic Motor Thalamus Neurons Improves Forelimb Akinesia in Parkinsonian Rats

Parkinson's disease (PD) is a motor disorder charactertised by altered neural activity throughout the basal ganglia-thalamocortical circuit. Electrical deep brain stimulation (DBS) is efficacious in alleviating motor symptoms, but has several notable side-effects, most likely reflecting the non-specific nature of electrical stimulation and/or the brain regions targeted. We determined whether specific optogenetic activation of glutamatergic motor thalamus (Mthal) neurons alleviated forelimb akinesia in a chronic rat model of PD. Parkinsonian rats (unilateral 6-hydroxydopamine injection) were injected with an adeno-associated viral vector (AAV5-CaMKII-Chrimson-GFP) to transduce glutamatergic Mthal neurons with the red-shifted Chrimson opsin. Optogenetic stimulation with orange light at 15 Hz tonic and a physiological pattern, previously recorded from a Mthal neuron in a control rat, significantly increased forelimb use in the reaching test (p < 0.01). Orange light theta burst stimulation, 15 Hz and control reaching patterns significantly reduced akinesia (p < 0.0001) assessed by the step test. In contrast, forelimb use in the cylinder test was unaffected by orange light stimulation with any pattern. Blue light (control) stimulation failed to alter behaviours. Activation of Chrimson using complex patterns in the Mthal may be an alternative treatment to recover movement in PD. These vector and opsin changes are important steps towards translating optogenetic stimulation to humans.

A comparison of sub-tenon block with peribulbar block in small-incision cataract surgery

Purpose

To compare the efficacy and safety of sub-tenon block to peribulbar block with respect to analgesia, akinesia, and complications.

Methods

It is an observational study conducted at a government hospital in Karnataka. Seventy patients who came to the ophthalmology OPD for small-incision cataract surgery (SICS) under local anesthesia were included in the study. The participants were divided into two groups of 35 as per the surgeon. The pain was evaluated at the time of administration of the block, during the surgery, and during the postoperative period of 4 h. Akinesia was noted in both the groups and the time of onset of akinesia was noted. Any complications associated with the block such as chemosis or subconjunctival hemorrhage were also noted. Statistical analysis was done using PSS version 25.0, where P &lt; 0.05 was considered significant.

Results

The baseline pain score was higher in the peribulbar group (1.57). The onset of akinesia was faster in sub-tenons (90.34 s). Complete akinesia was achieved in 82.9% of patients after peribulbar block. There was no significant difference in complications in both groups.

Conclusion

Sub-tenons block is an effective and safer technique of ocular anesthesia for SICS. It can be considered as an alternative to the conventional peribulbar block for SICS.

Comparison of analgesia and akinesia between sub-Tenon's capsule anesthesia and trans-Tenon's capsule retrobulbar anesthesia in vitrectomy

OBJECTIVES

We compared the effects of sub-Tenon's capsule anesthesia (STA) and trans-Tenon's capsule retrobulbar anesthesia (TTRBA) in 68 patients with epiretinal membrane.

METHODS

Either STA or TTRBA was induced with 3 mL of lidocaine (2%) before vitrectomy combined with phacoemulsification and aspiration (phacovitrectomy). Akinesia was evaluated by range of eye movement (ROEM) in upward, downward, nasal, and temporal directions at 4, 10, and 30 minutes after injection. Analgesia was evaluated with a visual analogue pain score, which ranged from 0 to 10.

RESULTS

The mean cumulative ROEMs were 1.44±1.02 corneal diameters (CDs) at 4 minutes, 0.55±0.76 CDs at 10 minutes, and 0.26±0.33 CDs at 30 minutes in patients who received STA; these values were 0.39±0.35 CDs at 4 minutes, 0.22±0.30 CDs at 10 minutes, and 0.13±0.29 CDs at 30 minutes in patients who received TTRBA. At both 4 and 10 minutes, the cumulative ROEMs in all directions, as well as the temporal ROEMs, were significantly larger in patients who received STA than in patients who received TTRBA. Pain scores did not significantly differ between groups at any time point.

CONCLUSIONS

STA and TTRBA produced identical degrees of analgesia, but akinesia was slower in patients who received STA. TTRBA might be preferable for patients undergoing brief vitrectomy.

Biopharmaceutical Potential of Selegiline Loaded Chitosan Nanoparticles in the Management of Parkinson's Disease

BACKGROUND

Selegiline hydrochloride, a hydrophilic anti-Parkinson' moiety, undergoes extensive first-pass metabolism and has low bioavailability. A process to obtain of selegiline (SH) loaded chitosan nanoparticles was attempted to circumvent the above problem, through intranasal delivery.

METHODS

SH loaded polymeric nanoparticles were prepared by ionic gelation of chitosan with tripolyphosphate, and stabilized by tween 80/ poloxamer 188. The resulting nanoparticles (NPs) were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, entrapment efficiency, particle size, zeta potential and surface morphology by scanning electron microscopy. Further, they were schematically evaluated for mucoadhesive strength, in-vitro drug release, release kinetics, pharmacokinetics, catalepsy, akinesia, in-vivo lipid peroxidation, nitrite levels, glutathione, catalase enzyme levels in brain and physicochemical stability parameters.

RESULTS

Selegiline nanoparticles (SP18) produced were in size of 63.1 nm, polydispersity index of 0.201, zeta potential of +35.2 mV, mucoadhesion of 65.4% and entrapment efficiency of 74.77%. Selegiline showed biphasic release from nanoparticles, over a period of 36 h, with Fickian diffusion controlled release profile. Maximum concentration of SH in plasma was recognized as 52.71 ng/ml at 2 h for SP18, 20.09 ng/ml at 1 h for marketed formulation, and 21.69 ng/ ml for drug solution. SH loaded NPs showed a reversive effect in catalepsy and akinesia behaviour. This effect was especially pronounced in rats receiving SH loaded CS-NPs. Significant decrease in lipid peroxidation and nitrite concentration; increase in reduced glutathione and catalase enzyme levels were obtained due to antioxidant characteristics of SH, which turned to be useful to treat Parkinson's disease.

CONCLUSION

Selegiline loaded chitosan nanoparticles form an effective non-invasive drug delivery system of direct nose to brain targeting in Parkinson's disease.

The effects of dual-task in patients with Parkinson's disease performing cognitive-motor paradigms

Patients with Parkinson's disease (PD) exhibit impaired dual-task (DT) performance. A recent meta-analysis confirmed that dual tasking severely affects walking performance in PD patients. However, one report indicated that a cycling DT paradigm has facilitative effects on cognition. We investigated the effects of dual tasking by using walking and cycling as motor tasks and revealed the clinical determinants associated with DT performance. Twenty-seven eligible participants were enrolled for clinical, cognitive-walking, and cognitive-cycling DT paradigm investigations. The mean age and age at onset of the patients were 59.87 ± 6.3 and 53.11 ± 8.4 years, respectively. Both the off- and on-state akinesia subscores were worse on the more-affected side than on the less-affected side. However, the DT effects on the cycling and gait outcomes on both the more-affected and the less-affected side showed no significant differences. The DT effect on the two motor tasks and cognitive performance during a concurrent walking task declined. Nevertheless, the DT effect on cognition improved during cycling. The present study also revealed that the levodopa equivalent daily dosage was highly associated with cognitive-cycling performance and that the akinesia subscore was the most relevant factor that contributed to cognitive-walking performance. In conclusion, DT facilitation or interference might be mediated by the type of motor task applied. The cognitive-cycling DT paradigm had a facilitative effect on cognition. Cycling exercise may diminish motor dysfunction has been investigated. We suggest that cognitive-cycling DT training is a potential adjuvant therapeutic strategy for patients with PD to promote motor and cognitive functions.

Gait bradykinesia: difficulty in switching posture/gait measured by the anatomical y-axis vector of the sole in Parkinson's disease

This study in Parkinson's disease examined how spatiotemporal parameters in gait bradykinesia link to difficulty in terminating posture and initiating gait locomotion. 41 idiopathic Parkinson's disease patients and 15 age-matched healthy subjects participated in this study. After the patients fixated on a visual-fixation-target, gait was triggered by visual or vocal cue-stimulus. The LED instructed subjects to quickly achieve their own comfortable walking speed on a level floor. The posterior-anterior force of the y-axis vectors of sole relating to soleus and tibialis-anterior EMGs were examined. Step-gain was defined as the duration of the swing-phase relative that of the contralateral stance-phase. Dynamic-ratio was defined as the duration the fore-foot phase relative to that of the ipsilateral stance-phase as forward-oriented movement in each step. The pause in tonic soleus EMG was defined as the off-latency of posture (termination) and the onset of a tibialis-anterior EMG-burst as the on-latency of gait. In Parkinson's disease, soleus off-latencies were prolonged, whereas tibialis-anterior on-latencies were less prolonged. Unsynchronized off/on-latency differences correlated with spatiotemporal parameters of dynamic-ratios, step-gains, gait-initiation, and gait speed in gait bradykinesia. Delayed EMG off-latencies correlated with prolonged motor-latencies in gait bradykinesia as delayed initial backward body-shift. A delayed and deficient initial backward body-shift of y-axis vector was linked to each difficulty in terminating posture and initiating gait, changing to random gait akinesia. Gait bradykinesia in Parkinson's disease stemmed from unsynchronized off/on-latency EMG activities, linking to each difficulty in terminating posture and initiating gait synergic movement through an initial backward body-shift.

NMDAR encephalitis presenting as akinesia in a patient with Parkinson disease

We describe the case of a woman with Parkinson disease who developed an N-methyl-d-aspartate receptor antibody-mediated encephalitis. As a novelty, the encephalitis presentation mimicked a worsening of the pre-existing extrapyramidal syndrome, manifesting mainly as severe bradykinesia and, eventually, akinesia. Brain MRI was normal, whereas cerebrospinal fluid (CSF) analysis disclosed unique-to-CSF oligoclonal bands. Prompt identification and timely immunotherapy led to a complete recovery.

Functional imaging correlates of akinesia in Parkinson's disease: Still open issues

Akinesia is a major manifestation of Parkinson's disease (PD) related to difficulties or failures of willed movement to occur. Akinesia is still poorly understood and is not fully alleviated by standard therapeutic strategies. One reason is that the area of the clinical concept has blurred boundaries referring to confounded motor symptoms. Here, we review neuroimaging studies which, by providing access to finer-grained mechanisms, have the potential to reveal the dysfunctional brain processes that account for akinesia. It comes out that no clear common denominator could be identified across studies that are too heterogeneous with respect to the clinical/theoretical concepts and methods used. Results reveal, however, that various abnormalities within but also outside the motor and dopaminergic pathways might be associated with akinesia in PD patients. Notably, numerous yet poorly reproducible neural correlates were found in different brain regions supporting executive control by means of resting-state or task-based studies. This includes for instance the dorsolateral prefrontal cortex, the inferior frontal cortex, the supplementary motor area, the medial prefrontal cortex, the anterior cingulate cortex or the precuneus. This observation raises the issue of the multidimensional nature of akinesia. Yet, other open issues should be considered conjointly to drive future investigations. Above all, a unified terminology is needed to allow appropriate association of behavioral symptoms with brain mechanisms across studies. We adhere to a use of the term akinesia restricted to dysfunctions of movement initiation, ranging from delayed response to freezing or even total abolition of movement. We also call for targeting more specific neural mechanisms of movement preparation and action triggering with more sophisticated behavioral designs/event-related neurofunctional analyses. More work is needed to provide reliable evidence, but answering these still open issues might open up new prospects, beyond dopaminergic therapy, for managing this disabling symptom.

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No clear picture of the neural bases of PD akinesia can be drawn from the literature.

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Akinesia should be disentangled from bradykinesia and hypokinesia.

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Movement initiation dysfunctions may arise from both motor and executive disorders.

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Future neuroimaging studies should probe more specific neurocognitive processes.

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Future studies should look beyond the dopaminergic basal-ganglia circuitry.

Interplay between adenosine receptor antagonist and cyclooxygenase inhibitor in haloperidol-induced extrapyramidal effects in mice

Antipsychotic drugs are the mainstay of psychotic disorders. The 'typical' antipsychotic agents are commonly employed for the positive symptoms of schizophrenia, though at an expense of extrapyramidal side effects (EPS). In the present study, we employed haloperidol (HP)-induced catalepsy model in mice to evaluate the role of adenosine receptor antagonist and cyclooxygenase (COX) enzyme inhibitor in the amelioration of EPS. HP produced a full blown catalepsy, akinesia and a significant impairment in locomotion and antioxidant status. Pre-treatment with COX inhibitor; naproxen (NPx) and adenosine receptor antagonist; caffeine (CAF), showed a significant impact on HP-induced cataleptic symptoms. Adenosine exerts pivotal control on dopaminergic receptors and is also involved in receptor internalization and recycling. On the other hand, prostaglandins (PGs) are implicated as neuro-inflammatory molecules released due to microglial activation in both Parkinson's disease (PD) and antipsychotics-induced EPS. The involvement of these neuroeffector molecules has led to the possibility of use of CAF and COX inhibitors as therapeutic approaches to reduce the EPS burden of antipsychotic drugs. Both these pathways seem to be interlinked to each other, where adenosine modulates the formation of PGs through transcriptional modulation of COXs. We observed an additive effect with combined treatment of NPx and CAF against HP-induced movement disorder. These effects lead us to propose that neuromodulatory pathways of dopaminergic circuitry need to be explored for further understanding and utilizing the full therapeutic potential of antipsychotic agents.

Pure akinesia with gait freezing: a clinicopathologic study

Background

Pure akinesia with gait freezing is a rare syndrome with few autopsied cases. Severe freezing of gait occurs in the absence of bradykinesia and rigidity. Most autopsies have revealed progressive supranuclear palsy. We report the clinical and postmortem findings of two patients with pure akinesia with gait freezing, provide video recordings of these patients, and review the literature describing similar cases. We also discuss bradykinesia, hypokinesia and akinesia in the context of this clinical syndrome.

Case presentation

Two patients with the syndrome of pure akinesia with gait freezing were examined by the same movement disorder specialist at least annually for 9 and 18 years. Both patients initially exhibited freezing, tachyphemia, micrographia and festination without bradykinesia and rigidity. Both autopsies revealed characteristic tau pathology of progressive supranuclear palsy, with nearly total neuronal loss and gliosis in the subthalamus and severe neuronal loss and gliosis in the globus pallidus and substantia nigra. Previously published postmortem studies revealed that most patients with this syndrome had progressive supranuclear palsy or pallidonigroluysian atrophy.

Conclusions

Pallidonigroluysian degeneration produces freezing and festination in the absence of generalized slowing (bradykinesia). Freezing and festination are commonly regarded as features of akinesia. Akinesia literally means absence of movement, and akinesia is commonly viewed as an extreme of bradykinesia. The pure akinesia with gait freezing phenotype illustrates that bradykinesia and akinesia should be viewed as separate phenomena.

Electronic supplementary material

The online version of this article (doi:10.1186/s40734-017-0063-1) contains supplementary material, which is available to authorized users.

Additional noradrenergic depletion aggravates forelimb akinesia and abnormal subthalamic nucleus activity in a rat model of Parkinson's disease

AIMS

This study aims to identify the contribution of additional noradrenergic depletion to forelimb akinesia and abnormal subthalamic nucleus (STN) firing activity in Parkinson's disease (PD).

MAIN METHODS

Forelimb akinesia behaviors were tested in awake rats with noradrenergic N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) lesions, unilateral 6-hydroxydopamine (6-OHDA) lesions in the substantia nigra pars compacta (SNc) and with combined 6-OHDA and DSP-4 lesions. STN extracellular single-unit and local field potential (LFP) activities were examined in the animals that were anesthetized with urethane.

KEY FINDINGS

The adjusting steps and the contralateral touches of rats in the forelimb akinesia behavior tests were markedly inhibited by a further noradrenergic lesion with DSP-4 in 6-OHDA+DSP-4-lesioned group when compared with those of 6-OHDA-lesioned animals (P<0.05 for all comparisons). Meanwhile, the neuronal firing pattern of STN also changed significantly towards more bursty in 6-OHDA + DSP-4-lesioned group (P <0 .05). Compared with 6-OHDA-lesioned animals, an additional noradrenergic lesion increased the 0.3-2.5 Hz oscillatory activity and the spike power of STN neurons (P < 0.01 for both comparisons), and strengthened the synchronized oscillation between subthalamic neuronal firing and LFP activity in 6-OHDA + DSP-4-lesioned group (P < 0.01).

SIGNIFICANCE

The results provide evidence to support the correlation between noradrenergic depletion and the further exaggerated dysfunction of STN electrical activity in PD and suggest that an aberrant noradrenergic system might play a specific role in the motor deficits of PD.

Akinetic crisis in Parkinson's disease is associated with a severe loss of striatal dopamine transporter function: a report of two cases

Akinetic crisis or acute akinesia is a life-threatening complication of Parkinson's disease (PD) with unknown pathophysiological mechanisms. Clinically, it resembles the neuroleptic malignant syndrome, and dopaminergic drugs are transiently ineffective in the acute phase of the condition. There are no published dopaminergic functional imaging studies on PD patients with akinetic crisis. Here we report 2 advanced PD patients with akinetic crisis who were scanned with SPECT using brain dopamine transporter ligand [(123)I]FP-CIT. The first patient was additionally scanned before the condition developed, and the second patient was scanned after recovery. Striatal dopamine transporter binding was lower during than before the crisis, and both patients showed a nearly complete loss of dopamine transporter binding during the crisis. Serial imaging showed that the uptake remained negligible despite an improvement in motor function after recovery. Akinetic crisis in PD appears to be associated with a particularly severe loss of presynaptic striatal dopamine function that does not improve after recovery. Apart from presynaptic dopaminergic function, other dopaminergic or nondopaminergic mechanisms are involved in the clinical improvement of motor functions after akinetic crisis in PD.

Posterior SMA Syndrome following subcortical stroke: contralateral akinesia reversed by visual feedback

BACKGROUND

The supplementary motor area (SMA) plays a key role in motor programming and production and is involved in internally-cued movements. In neurological populations, SMA syndrome following a lesion to the "SMA proper" is characterized by transient impairment of voluntary movements and motor sequences. This syndrome is assumed to follow on from an interruption of the motor cortico-subcortical loop, and some case reports indicate that such a syndrome could occur after a brain lesion isolating the SMA from subcortical structures.

AIM

To characterize the pattern of motor impairments in a patient whose stroke disconnects the SMA from the subcortical motor loop.

METHOD

A patient developed a moderate transient left hemiparesis following a subcortical stroke in the right anterior cerebral artery area, which disconnected the SMA from basal ganglia. Eight days after the stroke, when the hemiparesis had regressed, the patient presented a specific SMA motor disorder of the left hand which manifested as an akinesia and was exacerbated when his visual attention was not directed towards his hand. We assessed finger tapping with left and right hands, eyes closed and open, in the left and right hemispace. We indexed movement speed as the number of taps filmed over 5-s periods.

RESULTS

Left motor weakness (grasping strength of right hand: 49 kg and left hand: 41 kg) was resolved in a week. Ideomotor and ideational gestures and motor sequences were preserved. On the tapping task, left-hand tapping was slower than right-hand tapping. Critically, visual feedback improved tapping speed for the left, but not for the right, hand. The hemispace of the task execution had no effect on tapping performance.

CONCLUSION

Our results suggest that SMA-basal ganglia disconnection decreases contralateral movement initiation and maintenance and this effect is partly compensated by visual cues.