Slowly progressive L-DOPA nonresponsive pure akinesia due to nigropallidal degeneration: a clinicopathological case study

Pallidal degenerations and related disorders: an update

Neurodegenerative disorders involving preferentially the globus pallidus, its efferet and afferent circuits and/or related neuronal systems are rare. They include a variety of both familial and sporadic progressive movement disorders, clinically manifesting as choreoathetosis, dystonia, Parkinsonism, akinesia or myoclonus, often associated with seizures, mental impairment and motor or cerebellar symptoms. Based on the involved neuronal systems, this heterogenous group has been classified into several subgroups: "pure" pallidal atrophy (PPA) and extended forms, pallidonigral and pallidonigrospinal degeneration (PND, PNSD), pallidopyramidal syndrome (PPS), a highly debatable group, pallidopontonigral (PPND), nigrostriatal-pallidal-pyramidal degeneration (NSPPD) (Kufor-Rakeb syndrome /KRS), pallidoluysian degeneration (PLD), pallidoluysionigral degeneration (PLND), pallidoluysiodentate atrophy (PLDA), the more frequent dentatorubral-pallidoluysian atrophy (DRPLA), and other hereditary multisystem disorders affecting these systems, e.g., neuroferritinopathy (NF). Some of these syndromes are sporadic, others show autosomal recessive or dominant heredity, and for some specific gene mutations have been detected, e.g., ATP13A2/PARK9 (KRS), FTL1 or ATP13A2 (neuroferritinopathy), CAG triple expansions in gene ATN1 (DRPLA) or pA152T variant in MAPT gene (PNLD). One of the latter, and both PPND and DRPLA are particular subcortical 4-R tauopathies, related to progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and frontotemporal lobe degeneration-17 (FTLD-17), while others show additional 3-R and 4-R tauopathies or TDP-43 pathologies. The differential diagnosis includes a large variety of neurodegenerations ranging from Huntington and Joseph-Machado disease, tauopathies (PSP), torsion dystonia, multiple system atrophy, neurodegeneration with brain iron accumulation (NBIA), and other extrapyramidal disorders. Neuroimaging data and biological markers have been published for only few syndromes. In the presence of positive family histories, an early genetic counseling may be effective. The etiology of most phenotypes is unknown, and only for some pathogenic mechanisms, like polyglutamine-induced oxidative stress and autophagy in DRPLA, mitochondrial dysfunction induced by oxidative stress in KRS or ferrostasis/toxicity and protein aggregation in NF, have been discussed. Currently no disease-modifying therapy is available, and symptomatic treatment of hypo-, hyperkinetic, spastic or other symptoms may be helpful.

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.

Visualization of the internal globus pallidus: sequence and orientation for deep brain stimulation using a standard installation protocol at 3.0 Tesla

BACKGROUND

Deep-brain stimulation (DBS) of the internal globus pallidus (GPi) has shown remarkable therapeutic benefits for treatment-resistant neurological disorders including dystonia and Parkinson's disease (PD). The success of the DBS is critically dependent on the reliable visualization of the GPi. The aim of the study was to evaluate promising 3.0 Tesla magnetic resonance imaging (MRI) methods for pre-stereotactic visualization of the GPi using a standard installation protocol.

METHODS

MRI at 3.0 T of nine healthy individuals and of one patient with PD was acquired (FLAIR, T1-MPRAGE, T2-SPACE, T2*-FLASH2D, susceptibility-weighted imaging mapping (SWI)). Image quality and visualization of the GPi for each sequence were assessed by two neuroradiologists independently using a 6-point scale. Axial, coronal, and sagittal planes of the T2*-FLASH2D images were compared. Inter-rater reliability, contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) for the GPi were determined. For illustration, axial T2*-FLASH2D images were fused with a section schema of the Schaltenbrand-Wahren stereotactic atlas.

RESULTS

The GPi was best and reliably visualized in axial and to a lesser degree on coronal T2*-FLASH2D images. No major artifacts in the GPi were observed in any of the sequences. SWI offered a significantly higher CNR for the GPi compared to standard T2-weighted imaging using the standard parameters. The fusion of the axial T2*-FLASH2D images and the atlas projected the GPi clearly in the boundaries of the section schema.

CONCLUSIONS

Using a standard installation protocol at 3.0 T T2*-FLASH2D imaging (particularly axial view) provides optimal and reliable delineation of the GPi.

The clinical spectrum of freezing of gait in atypical parkinsonism

Freezing of gait (FOG), commonly seen in advanced Parkinson's disease (PD), has been classified as its fifth cardinal feature. However, its presence frequently leads to a misdiagnosis of PD. FOG is actually more common in atypical parkinsonism (AP): including vascular Parkinsonism (VP), progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD), dementia with Lewy bodies (DLB), and higher level gait disorders (HLGDs). VP is the result of multiple small vessel infarcts (lacunar state or Binswanger's disease), particularly involving the frontal, parietal, and basal ganglia regions. Approximately 50% have FOG (often referred to as lower body parkinsonism). FOG is also common in neurodegenerative forms of AP, present in 45-57%. Of these, FOG is present in 53% of PSP, 54% MSA, 54% DLB, 25% CBD, and 40% HLGD. It is generally seen in the late stages. There are two syndromes closely associated with AP that are dominated by FOG; pure akinesia (PA) and primary progressive freezing gait (PPFG). PA is characterized by akinesia of gait (including FOG), writing, and speech. Tremor, rigidity, dementia, and response to levodopa are notably absent. PPFG is defined by early FOG (often the initial feature) that progresses to include postural instability. It is accompanied by bradykinesia, rigidity, postural tremor, dementia, and levodopa unresponsiveness. Both syndromes are heterogeneous but PSP seems to be the most common cause. CBD and DLB can also present as PPFG. FOG is a common feature of AP and although typically occurring late in disease may also be an early symptom.

Pure akinesia with gait freezing: a third clinical phenotype of progressive supranuclear palsy

The clinical syndrome of pure akinesia has most often been associated with progressive supranuclear palsy (PSP) and is characterized by difficulty initiating gait and "freezing" during walking, writing and speaking. Similar syndromes have been described under the rubrics of primary progressive freezing gait and primary gait ignition failure. We investigated the specificity of the clinical syndrome of pure akinesia with gait freezing (PAGF) for PSP-tau pathology. Among 749 patients archived at the QSBB, only 7 fulfilled proposed diagnostic criteria of: gradual onset of freezing of gait or speech; absent limb rigidity and tremor; no sustained response to levodopa; and no dementia or ophthalmoplegia in the first 5 years of disease. In these cases detailed pathological examination was performed. PSP was the pathological diagnosis in six patients, and Parkinson's disease (PD) in the seventh. As defined, this syndrome had a positive predictive value of 86% for PSP-tau pathology. In the cases with PSP there were no additional features of coexistent vascular or PD and the median PSP-tau score was 3, reflecting relative mild tau load. The clinical syndrome of PAGF appears to have a high specificity for PSP-tau pathology. This relatively uncommon presentation of PSP-tau pathology has less severe tau accumulation than in the more common, "classic" PSP clinical phenotype: Richardson's disease.

Gait and dementia: moving beyond the notion of gait apraxia

Highest level gait disorders are produced by pathology in one or more structures in the cortical-basal ganglia-thalamocortical loop, which plays an important role in producing movements and postural synergies that meet personal desires and environmental constraints. Virtually all patients with dementia have pathology in one or more components of this loop, so highest level gait disorders are common in patients with dementia. The terminology surrounding these gait disorders is unnecessarily complex and too heavily influenced by the controversial concept of gait apraxia. Straightforward descriptive diagnostic criteria are needed. To this end, four core clinical features of highest level gait disorders are proposed: 1) inappropriate (counterproductive) or bizarre limb movement, postural synergies, and interaction with the environment, 2) qualitatively variable performance, influenced greatly by the environment and emotion, 3) hesitation and freezing, and 4) absent or inappropriate (counterproductive) rescue reactions. These core features follow logically from the physiology of the cortical-basal ganglia-thalamocortical loop and should be regarded as signs of pathology in this loop. A clinical rating scale based on these features should be developed to facilitate clinical diagnosis and clinicopathological correlation, while avoiding the ambiguities and controversies of gait apraxia.

A walking stick for a pure akinesia patient

We describe a 63-year-old female patient with pure akinesia whose gait was facilitated by a handmade converted walking stick. A posterior ventral pallidotomy had been performed, but it did not alleviate symptoms. Her husband made a walking stick with a wire loop at the bottom, perpendicular to the walking direction. When the patient stepped over the loop, the frozen gait was improved. This converted walking stick is easily made and inexpensive. Although the walking stick did not improve the patient's gait radically, use of the converted walking stick effectively improved the patient's daily life because successful treatment of pure akinesia cannot be established.

Obsessive-compulsive-like behavioral changes in pure akinesia

Pure akinesia is a disorder characterized by profound freezing in the absence of rigidity or tremor that is not improved by levodopa therapy. We report two cases of pure akinesia who developed obsessive-compulsive-disorder- (OCD-) like behavior during their illness. Although the pathophysiological mechanism underlying freezing is unclear, the coexistence of pure akinesia and OCD-like behavior suggests that both symptoms have a common pathological basis in these two cases, presumably damage to the pallidum.