Oculomotor Disorders Research Articles

A holographic waveguide based eye tracker.

We demonstrated the feasibility of using holographic waveguide for eye tracking. A custom-built holographic waveguide, a 20 mm x 60 mm x 3 mm flat glass substrate with integrated in- and out-couplers, was used for the prototype development. The in- and out-couplers, photopolymer films with holographic fringes, induced total internal reflection in the glass substrate. Diffractive optical elements were integrated into the in-coupler to serve as an optical collimator. The waveguide captured images of the anterior segment of the eye right in front of it and guided the images to a processing unit distant from the eye. The vector connecting the pupil center (PC) and the corneal reflex (CR) of the eye was used to compute eye position in the socket. An eye model, made of a high quality prosthetic eye, was used prototype validation. The benchtop prototype demonstrated a linear relationship between the angular eye position and the PC/CR vector over a range of 60 horizontal degrees and 30 vertical degrees at a resolution of 0.64-0.69 degrees/pixel by simple pixel count. The uncertainties of the measurements at different angular positions were within 1.2 pixels, which indicated that the prototype exhibited a high level of repeatability. These results confirmed that the holographic waveguide technology could be a feasible platform for developing a wearable eye tracker. Further development can lead to a compact, see-through eye tracker, which allows continuous monitoring of eye movement during real life tasks, and thus benefits diagnosis of oculomotor disorders.

Oculomotor and Vestibular Findings in Gaucher Disease Type 3 and Their Correlation with Neurological Findings

To evaluate the function of the oculomotor and vestibular systems and to correlate these findings with the clinical status of patients with Gaucher disease type 3 (GD3). The goal of this cross-sectional and longitudinal study was to find oculomotor biomarkers for future clinical trials. Twenty-six patients with GD3 were assessed for eligibility and 21 were able to perform at least one task. Horizontal and vertical reflexive saccades, smooth pursuit, gaze-holding, optokinetic nystagmus, and horizontal vestibulo-ocular reflex (VOR) were examined by video-oculography/video-head impulse test and compared concurrently with 33 healthy controls. The Scale for the Assessment and Rating of Ataxia (SARA), the modified Severity Scoring Tool (mSST), and Grooved Pegboard Test (GPT) were administered to assess overall neurological function. Eleven patients were also re-assessed after 1 year. Nine out of 17 patients exhibited gaze-holding deficits. One patient had upbeat nystagmus. Three patients presented with bilateral abducens palsy in combination with central oculomotor disorders, suggesting a bilateral involvement of the abducens nucleus. Horizontal angular VOR gain was reduced in all patients (0.66 ± 0.37) compared with controls (1.1 ± 0.11, p < 0.001). Most strongly correlated with clinical rating scales were peak velocity of downward saccades (SARA: ρ = -0.752, p < 0.0005; mSST: ρ = -0.611, p = 0.003; GPT: ρ = -0.649, p = 0.005) and duration of vertical saccades (SARA: ρ = 0.806, p < 0.001; mSST: ρ = 0.700, p < 0.0005; GPT: ρ = 0.558, p = 0.02) together with the VOR gain (SARA: ρ = -0.63, p = 0.016; mSST: ρ = -0.725, p = 0.003; GPT: ρ = -0.666, p = 0.004). Vertical smooth pursuit gain decreased significantly at follow-up. This study shows neuronal degeneration of the brainstem and cerebellum with combined involvement of both supranuclear and nuclear oculomotor structures and the vestibular system in GD3. We also identified oculomotor parameters that correlate with the neurological status and can be used as biomarkers in future clinical trials.

Preoperative and postoperative ophthalmic symptoms in patients with space-occupying lesions of the midbrain and pineal region

To identify patterns of neuro-ophthalmic symptoms before and after surgical treatment in patients with space-occupying lesions of the midbrain and pineal region. We analyzed neurological symptoms in 231 patients with space-occupying lesions of the midbrain and pineal region before and after surgical treatment. Malignant tumors were detected in 121 patients; benign tumors were present in 73 patients; 37 patients were diagnosed with pineal gland cysts. Patients with suspicion of germinoma underwent a tumor biopsy only; the other patients underwent tumor resection. Before surgery, oculomotor and pupil disorders were detected in more than half of the (67%) patients; ophthalmoscopic signs of intracranial hypertension were present in 38% of the patients. Neuro-ophthalmic symptoms significantly more often occurred in patients with malignant tumors. Midbrain symptoms were significantly more pronounced in germ cell tumors than in other malignant neoplasms. In the early postoperative period after tumor resection, deterioration of oculomotor and pupillary functions occurred in 46% of cases; there were no changes in 51% of cases; improvement occurred in 3% of cases. After tumor biopsy, symptoms in all patients with germinomas remained at the preoperative level. Developed symptoms partially regressed in the long-term period, and finally, only 29% of patients had deterioration of oculomotor and pupillary functions compared to the preoperative level.

Extended endoscopic endonasal posterior (transclival) approach to tumors of the clival region and ventral posterior cranial fossa. Part 3. Analysis of surgical treatment outcomes in 127 patients

To improve and introduce the extended endoscopic endonasal posterior (transclival) approach into clinical practice and to analyze the results of its application in surgical treatment of midline skull base tumors extending into the ventral posterior cranial fossa. During the period from 2008 to the present, we have operated 127 patients with various skull base tumors located in the clival region and ventral posterior cranial fossa (60 males and 67 females); the patients' age was 3 to 74 years. The distribution of tumors by histology was as follows: 96 (75.6%) chordomas, 9 (7.1%) pituitary adenomas, 8 (6.3%) meningiomas, 3 (2.33%) cholesteatomas, 2 (1.6%) craniopharyngiomas, 3 (2.33%) fibrotic dysplasia, and 6 (4.7%) other tumors (giant cell tumor, glioma of the neurohypophysis, osteoma, plasmacytoma, carcinoid tumors, chondroma). The tumor size was as follows: 36 (28.35%) giant (more than 60 mm) tumors, 71 (55.9%) large (35-59 mm) tumors, 19 (14.96%) medium (21-35 mm) tumors, and 1 (0.79%) small (less than 20 mm) tumor. Intraoperative monitoring of the cranial nerves was performed (20 cranial nerves were identified) in 10 cases. The extent of chordoma resection was as follows: total removal - 63 (65.62%) cases, subtotal removal - 23 (23.96%) cases, and partial removal - 10 (10.42%) cases. Pituitary adenomas were resected totally in 6 cases, subtotally in 1 case, and partially in 2 cases. Meningioma was removed subtotally in 4 cases, partially in 3 cases, and less than 50% in 1 case. Other tumors (cholesteatoma, craniopharyngioma, fibrous dysplasia, giant cell tumor, glioma of the neurohypophysis, osteoma, plasmacytoma, carcinoid tumors, chondroma) were removed totally in 7 cases and subtotally in 7 cases. Postoperative cerebrospinal fluid leakage occurred in 9 (7.2%) cases, and meningitis developed in 12 (9.4%) cases. Oculomotor disorders occurred in 17 (13.4%) patients; in 10 of these patients, the disorders regressed within 4 to 38 days after surgery; in 7 patients the oculomotor disorders did not regress. A lethal outcome occurred in 2 (1.57%) cases. The extended endoscopic endonasal posterior (transclival) approach, being minimally invasive, enables removal of various midline skull base tumors with/without involvement of the clivus with high radicalness, low risk of postoperative complications, and low lethality. Until recently, these tumors were considered almost inoperable.

A Case of Mitochondrial Disease First Diagnosed Over 30 Years After Onset

Mitochondrial disease is induced by mutations in both mitochondrial DNA and DNA of nuclear genes that encode mitochondrial proteins, and there is a general lack of genotype-phenotype correlation in many mitochondrial disorders, which makes the diagnosis of mitochondrial disease difficult. We treated a 37-year-old woman with congenital cataract, bilateral sensory deafness, severe bilateral ptosis, oculomotor disorder in all directions and systemic muscular atrophy and weakness. These clinical characteristics made us perform further examinations, and we found ischemic change in brain and remarkable atrophy of extraocular muscles by magnetic resonance imaging (MRI), optic atrophy by fundus examination and high levels of serum lactate and lactate/pyruvate ratio, which confirmed the diagnosis of mitochondrial disease. Finally, she was diagnosed with having mitochondrial disease for over 30 years after onset. J Endocrinol Metab. 2018;8(6):149-152 doi: https://doi.org/10.14740/jem542

Complications after endoscopic endonasal transsphenoidal removal of pituitary adenomas

The use of endoscopic technique has significantly extended the indications for surgery using the transsphenoidal approach. Currently, more than 90% of pituitary adenomas are operated on transsphenoidally. Transnasal removal of giant pituitary adenomas has become possible. Transition to the endoscopic endonasal approach in removal of pituitary adenomas changed the rate and structure of postoperative complications. We analyzed potential complications after endoscopic endonasal transsphenoidal removal of pituitary adenomas. These include complications of the approach itself (nasal bleeding, perforation of the nasal septum, impaired olfactory function, atrophic rhinitis, synechiae, mucoperiosteal flap necrosis, and external nasal deformities), infectious complications (meningitis, intracranial abscesses), cerebral circulation disorder (subarachnoid hemorrhage, cerebral vasospasm, injury to large vessels, intracranial hematomas), neuro-ophthalmological complications (visual and oculomotor disorders), endocrine (hypopituitarism, diabetes insipidus, hyponatremia) and somatic complications, and nasal liquorrhea. In conclusion, it should be noted that despite continuous improvement of the technique for endoscopic endonasal removal of pituitary adenomas, there is a risk of serious complications, which necessitates the development of techniques for prevention of these complications.

A Case of Mitochondrial Disease First Diagnosed Over 30 Years After Onset

Mitochondrial disease is induced by mutations in both mitochondrial DNA and DNA of nuclear genes that encode mitochondrial proteins, and there is a general lack of genotype-phenotype correlation in many mitochondrial disorders, which makes the diagnosis of mitochondrial disease difficult. We treated a 37-year-old woman with congenital cataract, bilateral sensory deafness, severe bilateral ptosis, oculomotor disorder in all directions and systemic muscular atrophy and weakness. These clinical characteristics made us perform further examinations, and we found ischemic change in brain and remarkable atrophy of extraocular muscles by magnetic resonance imaging (MRI), optic atrophy by fundus examination and high levels of serum lactate and lactate/pyruvate ratio, which confirmed the diagnosis of mitochondrial disease. Finally, she was diagnosed with having mitochondrial disease for over 30 years after onset. J Endocrinol Metab. 2018;8(6):149-152 doi: https://doi.org/10.14740/jem542

Videonystagmography in the diagnosis of oculomotor disorders

Videostagmography is a dynamically developing method of objective quantitative eye movement recording in various neurological diseases which has a few advantages over those used previously. The review describes the basics of the method and the most commonly used tests for a number of eye movements. The principles of research into various types of saccades, including pro-saccades, antisaccades, memory-guided saccades and voluntary saccades, as well as other types of eye movements such as smooth pursuit and optokinetic nystagmus, are also covered. Reviewed are parameters which need to be assessed in each case, with possible deviations in these parameters to be recorded during videonystagmography in patients with neurological diseases. Data from previously published studies allowing to anticipate the development of a technique that would enable the presymptomatic and early differential diagnosis of a number of diseases are presented. The review also considers the potential influence of the disease progression, as well as of therapeutic interventions, on the parameters assessed during videonystagmography.

Wernicke–Korsakov Syndrome

Objective. To study the characteristics of the diagnosis and treatment of non-alcoholic-related Wernicke–Korsakov syndrome (WKS). Materials and methods. Eight patients (five men and three women) with mean age 38.9 ± 1.4 years with WKS were observed; WKS in three patients developed on the background of acute and two on the background of exacerbations of chronic gastrointestinal tract diseases with malabsorption, and in three after surgery to the upper segments of the gastrointestinal tract Results. Illness debuted with impaired consciousness. Symptoms of ataxia, oculomotor disorders, and bulbar syndrome started after 24–48 h. One patient developed a treatment-resistant state of tonic-clonic seizures. The brain MRI picture was characterized by the presence of hyperintense foci on T2-weighted images in the areas of the hypothalamus, mammillary bodies, brainstem, and cerebellum, with accumulation of contrast in the mammillary bodies. Patients received treatment with a complex of group B vitamins (Neurobion) and thiamine, with positive results Conclusions. Patients with gastrointestinal tract diseases accompanied by malabsorption are at risk of developing WKS. The appearance of changes in consciousness, ataxia, and oculomotor disorders in these patients is an indication to start thiamine therapy, thus preventing the development of stable cognitive deficit.

Neuroanatomical Structures in Human Extraocular Muscles and Their Potential Implication in the Development of Oculomotor Disorders.

The potential role of sensory feedback from human extraocular muscles has been subjected to considerable speculation in the ophthalmic literature. Extraocular muscles pull against a fairly even load and do not initiate a stretch reflex, even when the eyes are directed toward the boundaries of their respective field of action. These unique working conditions and physiological properties have led to the notion that the sensory signal arising from receptors in extraocular muscles differs from the conventional proprioceptive signal arising from their somatic counterparts. The interest in the receptors at the myotendinous junction of human extraocular muscles has been renewed due to their alleged role in the development of binocular vision and their potential implication in the etiology of binocular vision anomalies. The idea that extraocular muscles provide knowledge of eye position and whether this function can be affected by surgical intervention has initiated several clinical and neuroanatomical studies. Many of these studies support this concept and suggest that surgical procedures that impose only minimal interference with the proprioceptive signal will give a better postoperative result. However, other studies contradict this view because the afferent capacity of the receptors can be questioned and some uncertainties remain. The purpose of this study was to review the related literature and discuss the possible role of ocular proprioceptors in relation to binocular vision and the development of eye motility disorders. [J Pediatr Ophthalmol Strabismus. 2018;55(1):14-22.].

Clinical application of eye movement tasks as an aid to understanding Parkinson's disease pathophysiology.

Parkinson's disease (PD) is a progressive neurodegenerative disorder of the basal ganglia. Most PD patients suffer from somatomotor and oculomotor disorders. The oculomotor system facilitates obtaining accurate information from the visual world. If a target moves slowly in the fronto-parallel plane, tracking eye movements occur that consist primarily of smooth-pursuit interspersed with corrective saccades. Efficient smooth-pursuit requires appropriate target selection and predictive compensation for inherent processing delays. Although pursuit impairment, e.g. as latency prolongation or low gain (eye velocity/target velocity), is well known in PD, normal aging alone results in such changes. In this article, we first briefly review some basic features of smooth-pursuit, then review recent results showing the specific nature of impaired pursuit in PD using a cue-dependent memory-based smooth-pursuit task. This task was initially used for monkeys to separate two major components of prediction (image-motion direction memory and movement preparation), and neural correlates were examined in major pursuit pathways. Most PD patients possessed normal cue-information memory but extra-retinal mechanisms for pursuit preparation and execution were dysfunctional. A minority of PD patients had abnormal cue-information memory or difficulty in understanding the task. Some PD patients with normal cue-information memory changed strategy to initiate smooth tracking. Strategy changes were also observed to compensate for impaired pursuit during whole body rotation while the target moved with the head. We discuss PD pathophysiology by comparing eye movement task results with neuropsychological and motor symptom evaluations of individual patients and further with monkey results, and suggest possible neural circuits for these functions/dysfunctions.

Neurodevelopmental Problems in Children at 9 Months of Age Associated with Neonatal Hypoxic-Ischemic Encephalopathy

Introduction: Neonatal asphyxia is a major cause of infant morbidity in Cameroon. The aim of this study was to describe the short-term neurological outcome of children following neonatal Hypoxic-ischemic encephalopathy (HIE). Methodology: We conducted a retrospective cohort study from May 2010 to September 2013. We included 39 exposed cases against 78 non-exposed cases followed-up for at least 9 months. The variables studied were: age, sex, head circumference, neurological sequelae, postural anomalies and motor skills and developmental age/quotient. The data collected were analyzed using Epi info software version 3.5.3. The Fisher Exact Test was used to compare the variables with a significance threshold defined for p < 0.05. Results: We recruited 39 cases for 78 controls. The majority (74.40%) of cases were classified as HIE Sarnat 3 and 25.60% Sarnat 2. Most of the children were aged 12 - 36 months with a mean age of 18 months. The male sex was predominant with a sex ratio of 1.2; and 61.50% of children with HIE had head circumference < -2 Zscore. Thirtyone (79.50%) of the exposed cases developed a handicap against 2 (2.60%) in the control group. The handicaps were 61.54% severe, 10.26% moderate and 7.70% mild. The main sequelae were mental retardation (66.70%), cerebral palsy (46.20%) and epilepsy (30.80%). The associated anomalies were microcephaly and bucco facial dyspraxia. The neurosensory disorders consisted of blindness (41%), oculomotor disorders (18%) and deafness (7.70%). The mean developmental quotient in the cases was 49.59%. Conclusion: The frequency of neurological sequelae following HIE was high in our series. Efforts should be made to prevent perinatal asphyxia and to ensure the availability of material and staff trained to help babies’ breath in all the delivery rooms in our maternities.

The neurological disorders under schizophrenia: clinical characteristics and pathogenic aspects

The review considers neurological disorders diagnosed in patients with schizophrenia. It is emphasized that these disorders can occur in patients without treatment with neuroleptics. The light neurological disorders are quite often given no proper consideration. The development of these disorders is based on phenomenon of uncoupling of frontal lobes with other sections of brain, both cortical and sub cortical ones. The description of disorders of motor functions is presented. At that, particular attention is paid to parkinsonism, dyskinesia, oculomotor disorders. The pathogenic aspects of neurological disorders in patients with schizophrenia are considered. The results of study applied to this category of patients using technique of structural and functional neurovisualization are presented. It is emphasized that further investigation of this problem will permit bettering comprehend pathogenesis of this disease with the purpose of development of more effective therapy.

Visual and oculomotor disorders in patients with multiple sclerosis in connection with comorbidity

Conducted study visual and oculomotor disorders in patients with multiple sclerosis (MS) to identify the features of their occurrence and determination due to the performance quality of life, level of fatigue, depression, pain, cognitive impairment in terms of comorbidity. It examined 207 patients with different forms of MS course. The average prevalence of visual impairment in our studied patients with MS was 56.0% and -81.2% oculomotor disorders. It was found that in patients with MS comorbidity, visual disturbances and oculomotor disorders have greater prevalence and severity. The severity of visual disorders are closely correlated (p &lt;0.05) with the level of depression and cognitive impairment, and the severity of the eye disorders - fatigue level of p &lt;0.05.

Eye position under general anesthesia in orthophoric children

PurposeThe aim of this study is to evaluate the effect of general anesthesia with muscle relaxant on the horizontal ocular deviation in orthophoric children.MethodsChildren aged 4–16 years requiring a non‐ophthalmological surgical procedure under general anesthesia with neuromuscular blockade were included. Prior ophthalmological examination excluded any oculomotor disorder. Horizontal ocular deviation was measured by the Hirschberg photographic method by comparing pictures taken in the awakened state to those taken under general anesthesia. Monitoring of anesthesia was performed by the Bispectral index (BIS) and muscle relaxation by the train of four (TOF).Results33 Patients were included. Mean age was 8(±4) years and 67.7% were male. The mean horizontal ocular deviation after general anesthesia with neuromuscular blockade was −0.2 diopters (SD 9.7). Median was −0.7 diopters. 72.7% of patients had an ocular deviation of less than 7.5 diopters with a normal distribution.ConclusionsOur results show that contrary to popular belief, eye position under general anesthesia in children without strabismus is not divergent but very close to orthophoria.

The factors responsible for impairment of vision and the algorithm for the regular medical check-up of the patients following retinopathy of prematurity

Objective. To develop the algorithm for the regular medical check-up of the patients following retinopathy of prematurity based on the investigation of the main factors responsible for the impairment of vision in the patients presenting with this pathology. Material and methods. A total of 655 patients (1307 eyes) at the age varying from 4 to 18 years with cicatrical retinopathy of prematurity were available for the examination, The standard methods employed for the ophthalmological examination were supplemented by optical coherent tomography, retinal tomography, registration of different kinds of electroretinograms, multichannel visual evoked potentials, computed perimetry, evaluation of spatial contrast sensitivity. Results. It was shown that the main factors responsible for the impairment of vision in the patients presenting with retinopathy of prematurity are the following ones: (1) the degree of residual changes in the fundus at the cicatrical stage of retinopathy of prematurity, (2) late complications, (3) the concomitant pathology of the conduction pathways and higher portions of the visual analyzer, (4) concomitant eye pathology, (5) refractive and oculomotor disorders, (6) functional incompetence of the retina due to prematurity and/or the consequences of retinopathy of prematurity suffered in the past. Conclusion. The organization of the regular medical check-up of the patients following retinopathy of prematurity implies the necessity of the comprehensive clinical and functional examination throughout the entire lifespan of the subjects with this pathology for the purpose of timely identification and correction of the revealed disorders.

Delineating the GRIN1 phenotypic spectrum: A distinct genetic NMDA receptor encephalopathy.

Objective:To determine the phenotypic spectrum caused by mutations in GRIN1 encoding the NMDA receptor subunit GluN1 and to investigate their underlying functional pathophysiology.Methods:We collected molecular and clinical data from several diagnostic and research cohorts. Functional consequences of GRIN1 mutations were investigated in Xenopus laevis oocytes.Results:We identified heterozygous de novo GRIN1 mutations in 14 individuals and reviewed the phenotypes of all 9 previously reported patients. These 23 individuals presented with a distinct phenotype of profound developmental delay, severe intellectual disability with absent speech, muscular hypotonia, hyperkinetic movement disorder, oculogyric crises, cortical blindness, generalized cerebral atrophy, and epilepsy. Mutations cluster within transmembrane segments and result in loss of channel function of varying severity with a dominant-negative effect. In addition, we describe 2 homozygous GRIN1 mutations (1 missense, 1 truncation), each segregating with severe neurodevelopmental phenotypes in consanguineous families.Conclusions:De novo GRIN1 mutations are associated with severe intellectual disability with cortical visual impairment as well as oculomotor and movement disorders being discriminating phenotypic features. Loss of NMDA receptor function appears to be the underlying disease mechanism. The identification of both heterozygous and homozygous mutations blurs the borders of dominant and recessive inheritance of GRIN1-associated disorders.

Пролактиноми: чи можлива хірургічна гормональна ремісія?

Prolactinomas: is it possible to achieve hormonal remission surgically? Purpose. Tо determine the efficacy of endoscopic endonasal transsphenoidal method for the treatment of prolactinomas.Materials and methods. Endoscopic endonasal trassphenoidal (EET) access was performed in all cases. Depending on the size, we were isolated: the pituitary microadenomas (up to 10mm) – 6 macroadenomas (10–40 mm) – 12 giant adenomas (&gt;40 mm) – 3. Clinical manifestations were presented in: visual disorders – 9 patients, including: visual acuity – 6, visual field disorders – 3, diplopia – 2; hormonal disorders – 14 patients, including: menstruation disorders – 9, obesity – 4 galactorrhea – 3.Results and discussion. The average serum prolactin was 530 ng/ml, the maximum levels was – 1440 ng/ml, the minimum was – 65 ng/ml. Normal prolactin level was achieved postoperatively in 5 (100%) cases of microadenomas, and in 7 (58,3%) cases of macroadenomas without DA. After EET surgery normoprolactinemia was achieved in 12 (60%) patients, 8 (40%) cases required DA therapy within a year. Hormonal disorders’ remission after surgery was achieved in 10 (76,9%) cases. In 6 (30%) cases, any hormonal disorders ware identified. Visual acuity was improved in all cases. Any postoperative complications like CSF leak, meningitis, additional oculomotor disorders or any other visual disorders were identified. No mortality was observed in our research.Conclusions. Endoscopic endonasal transsphenoidal technique is effective for prolactinomas treatment and allows to improve rate of hormone level in 60%. In case of microprolactinomas improving hormone level and hormonal disorders is possible in 100% without DA therapy.

Impact of cerebellar atrophy on cortical gray matter and cerebellar peduncles as assessed by voxel-based morphometry and high angular resolution diffusion imaging.

In recent years the cerebellum has been attributed amore important role in higher-level functions than previously believed. We examined a cohort of patients suffering from cerebellar atrophy resulting in ataxia, with two main objectives: first to investigate which regions of the cerebrum were affected by the cerebellar degeneration, and second to assess whether diffusion magnetic resonance imaging (dMRI) metrics within the medial (MCP) and superior cerebellar peduncle (SCP) - namely fractional anisotropy (FA) and radial diffusivity (RD) - could be used as a biomarker in patients with this condition. Structural and dMRI data of seven patients with cerebellar atrophy (2 with spinocerebellar atrophy type 2, 1 with Friedreich's ataxia, 4 with idiopathic cerebellar ataxia) and no visible cortical lesions or cortical atrophy were investigated with Freesurfer and voxel-based morphometry (VBM) of gray matter (GM) as well as MCP and SCP FA maps. Correlations of MCP and SCP mean FA with ataxia scores and subscores were also evaluated. Freesurfer showed that patients had significantly reduced volume of the thalamus, ventral diencephalon and pallidum. VBM also demonstrated significantly lower local GM volumes in patients, notably in the head of the caudate nucleus, posterior cingulate gyrus and orbitofrontal cortex bilaterally, as well as in Broca's area in the left hemisphere, and a significant increase in RD in the MCP and SCP of both hemispheres. A significant correlation was found between MCP mean FA and total ataxia score (R=-0.7, p=0.03), and subscores for kinetic functions (R=-0.74, p=0.03) and oculomotor disorders (R=-0.70, p=0.04). The regions of the cerebrum found to have significantly lower local GM volumes have been described to be involved in higher-level cerebellar functions such as initiation of voluntary movements, emotional control, memory retrieval and general cognition. Our findings corroborate recent research pointing to a more extensive corticocerebellar system than previously thought. The significant difference in the MCP and SCP dMRI metrics between patients and controls as well as the significant correlation with ataxia total score and subscores support the use of dMRI metrics as an imaging biomarker for cerebellar degeneration and ataxia.

Challenges with the differential diagnosis of progressive supranuclear palsy and Parkinson’s disease

Progressive supranuclear palsy (PSP) is a severe old-age neurodegenerative disease that is characterized by pronounced clinical polymorphism and has different phenotypes. Practical differential diagnosis of PSP and Parkinson’s disease (PD) presents significant challenge, especially in onset of the disease. We report an atypical case of PSP characterized by symmetric levodopa-resistant parkinsonian syndrome, early postural instability, supranuclear oculomotor disorders (vertical gaze palsy), MR signs of midbrain atrophy, and a number of overlapping clinical symptoms similar with the manifestations of PD. A detailed algorithm of differential diagnosis of PSP and PD as well as a more adequate diagnostic formulation are proposed for this and similar cases of neurodegenerative pathology.