Impulse control disorders in Parkinson's disease: Review of pathophysiology, epidemiology, clinical features, management, and future challenges.

Impulsive-compulsive behavior (ICB) in Parkinson's disease (PD) suggests a combination of impulse control disorders (ICDs), such as pathological gambling, hypersexuality, compulsive eating, excessive buying, and compulsive behaviors, such as punding, dopamine dysregulation syndrome (DDS), hoarding, and hobbyism. Hypersexuality and gambling are common in male patients while compulsive buying is common in women patients. Recent studies reveal the prevalence of ICB to be more than 25% among the PD patients. The nigrostriatal, mesocortical, and mesolimbic dopaminergic pathways play a crucial role in the pathogenesis of ICDs in PD patients. The greater tonic release of dopamine creates a state of relative dopamine deficit and reduced reward sensation and impulsive behaviors. The major risk factors for ICB are the use of dopamine agonist (DA), male gender, young patient, depression, smoking, drug abuse, Parkin mutation, and family history of ICDs. Single nucleotide polymorphism in dopamine receptors D1, D2, and D3 also acts as a major risk factor. Questionnaire for impulsive-compulsive disorders in PD is the most widely adopted screening tool for the detection of ICB in PD. The major treatment for PD is to discontinue DAs and use prolonged release formulation of the DAs. The role of deep brain stimulation (DBS) and apomorphine in the treatment of ICB is still uncertain. Though DBS can reduce the risk of DDS, it can precipitate new ICBs such as hypersexuality.

Referral practice, reporting standards, and the impact of dopamine transporter scans done in a tertiary hospital.

AIMS: We studied the referral practice, reporting standards, and the impact of 123 ioflupane single photon emission computed tomogram dopamine transporters (DAT-SPECT) scans conducted for the diagnosis and clinical management of patients. SETTINGS AND DESIGNS: The present study was a retrospective, non-interventional study. MATERIALS AND METHODS: We assessed the DAT scan referral and the official reports available from the Nuclear Medicine Department of the Mater Misericordiae University Hospital over 1 year (2013). We also assessed the impact of the DAT scan result on the management of patients by analyzing patient records. The European Association of Nuclear Medicine Neuroimaging (EANM) 2010 and the Federal Drug Administration (FDA) 2012 guidelines were taken as the standard against which the quality of our DAT scans reporting was assessed. STATISTICAL METHODS: Microsoft Excel 2010 and graphpad software were used for statistical analysis. RESULTS: Twenty five (56.2%) out of a total of 48 DAT scans were performed to confirm early Parkinson's disease, 5 (8.9%) were done to exclude drug-induced parkinsonism, and 8 (14.3%) to distinguish essential tremor from parkinsonism; 2 scans were performed to distinguish Lewy body diseases from Alzheimer's dementia, and 4 indications were outside the recommended guidelines. Twelve out of the 26 (46%) abnormal scans had bilateral abnormalities. Twenty one out of the 25 DAT scans proved the clinical diagnosis of degenerative parkinsonism to be correct. CONCLUSION: The overall compliance of the DAT imaging with the existing standard guidelines was good. DAT scan can be very useful in clinical practice because it influences the clinical diagnosis and management in 23% of the patients.

Case series of autosomal recessive hereditary spastic paraparesis with novel mutation in SPG 7 gene.

Autosomal recessive hereditary spastic paraparesis is rare.We present 4 patients with slowly progressive predominantly lower limb spasticity and ataxia. Only one patient had family history of ataxia but without any underlying diagnosis. All of them proved negative for the mutation of Spinocerebelalr ataxia genes SCA 1,2,3 and 6. All had mutation in the SPG 7 gene suggestive of autosomal recessive hereditary spastic paraparesis. One of the heterozygous mutatnts showed a novel c1617delC ,p(Val540fs) frameshift mutation in exon 12 of the SPG 7 gene. SPG7 mutation accounts for 1.5-7% of all the HSP but it is the cause of undiagnosed ataxia in 18.6% in a recent case series. SPG7 mutation should be remembered as an important cause of undiagnosed ataxia especially where next generation sequencing is not widely avaialbale or affordable.

Pick's Disease Presenting as Tremulous Parkinsonism with Limited Levodopa Response-A Rare Cause of Corticobasal Syndrome.

BACKGROUND: Corticobasal syndrome is a clinical diagnosis and common pathological causes are corticobasal degeneration, progressive supranuclear palsy and Alzheimer's disease. OBJECTIVES: We would like to highlight a rare but important differential of corticobasal syndrome. METHODS: A 78-year-old female had a 4-year history of predominantly right-hand rest tremor, worsening of handwriting but no change in cognition. The clinical examination showed right upper limb postural and kinetic tremor, mild wrist rigidity and reduced amplitude of right-sided finger tapping. She was initially diagnosed as idiopathic Parkinson's disease. Five years after onset of symptoms, she demonstrated bilateral myoclonic jerks and right upper limb dystonic posturing. She could not copy movements with the right hand. The magnetic resonance imaging (MRI) revealed disproportionate atrophy in the parietal lobes bilaterally. The clinical diagnosis was changed to probable corticobasal syndrome. She passed away 11 years from onset of symptoms at the age of 85 years. She underwent a post-mortem. RESULTS: The anterior and posterior frontal cortex, anterior cingulate, temporal neocortex, hippocampus and amygdaloid complex demonstrated considerable tau-related pathology consisting of a dense background of neuropil threads, and rounded, paranuclear neuronal inclusions consistent with Pick bodies. The immunostaining for three microtubule binding domain repeats (3R) tau performed on sections from the frontal and temporal lobes, basal ganglia and midbrain highlighted several inclusions whilst no 4R tau was observed. She was finally diagnosed with Pick's disease. CONCLUSIONS: Pick's disease can rarely present with clinical features of corticobasal syndrome.

Frontotemporal Dementia-Parkinsonism Due to MAPT Gene Variant Presenting with Rest and Action Tremor.

A 50-year-old male presented with a four-year history of gradually progressive rest tremor in the distal right lower limb and then spreading to the left lower limb in last 10-12 months. He developed right arm rest and action tremor two years later. Magnetic resonance imaging scans showed progressive frontotemporal and asymmetrical mesial temporal atrophy. Genetic testing revealed a heterozygous c.915+16C>T pathogenic variant in intron 9 of the MAPT gene. Presentation with rest tremor should not exclude frontotemporal dementia-parkinsonism due to a MAPT variant as a differential diagnosis though rest tremor is a rare presentation.

Generalized Dystonia Due to a Pathogenic THAP1 Variant Showing Sustained Response to Globus Pallidus Deep Brain Stimulation.

A 21-year-old woman of south Asian origin presented with cervical dystonia which had progressed over the previous three years. Her symptoms started as writer's cramp since the age of seven years. She did not respond to medications and needed botulinum toxin injection for generalised dystonia. Subsequent whole genome sequencing revealed a likely pathogenic c.98G>A p.(Cys33Tyr) heterozygous variant in the THAP1 gene. She underwent bilateral posteroventral globus pallidus interna (GPi) deep brain stimulation (Medtronic Activa PC) implantation at the age of thirty-one years. She responded well to the deep brain stimulation even after more than 8 years post-surgery though she needs botulinum toxin injection for her cervical dystonia.

Corneal confocal microscopy demonstrates varying degrees of neurodegeneration in atypical parkinsonian disorders.

OBJECTIVE: We have used corneal confocal microscopy (CCM) to identify corneal nerve loss as a potential marker of neurodegeneration in participants with Parkinson's disease (PD), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). METHODS: Patients with PD (n = 19), PSP (n = 11), MSA (n = 8) and healthy controls (n = 18) underwent neurological assessment and CCM. RESULTS: Corneal nerve fibre density was significantly lower in participants with PD (p = 0.005), PSP (p = 0.005) and MSA (p = 0.0003) compared to controls. Corneal nerve branch density was significantly lower in participants with PD (p = 0.01) and MSA (p = 0.019), but not in participants with PSP (p = 0.662), compared to controls. Corneal nerve fibre length was significantly lower in participants with PD (p = 0.002) and MSA (p = 0.001) but not in participants with PSP (p = 0.191) compared to controls. CONCLUSION: CCM detects corneal nerve loss in participants with PD and MSA and to a lesser extent in PSP compared to healthy controls.

Pure Autonomic Failure-A Localized Alpha Synucleinopathy with a Potential for Conversion to More Extensive Alpha Synucleinopathies.

Pure autonomic failure (PAF) is an alpha synucleinopathy with predominant involvement of the autonomic ganglia and peripheral nerves. The hallmark clinical feature is orthostatic hypotension. However, genitourinary, sudomotor, and cardiac involvement is also common. Many patients also develop supine hypertension. Almost a quarter of patients can phenoconvert or evolve into Parkinson's disease, multiple system atrophy, and Lewy body dementia in the future. Early severe bladder involvement, higher supine noradrenaline level, early motor involvement, and dream enactment behavior increase the risk of phenoconversion. The diagnosis is confirmed via autonomic function testing and serum noradrenaline measurement. The treatment is mainly supportive. The non-pharmacological treatment includes adequate fluid, dietary salt, compression stockings, and abdominal binders. The drug therapies to improve blood pressure include midodrine, fludrocortisone, pyridostigmine, and droxidopa. The diagnostic criteria need to be updated to incorporate the recent understandings. The treatment of orthostatic hypotension and supine hypertension is mainly based on case series and anecdotal reports. Randomized control trials are needed to ascertain the best treatment strategies for PAF.

C19orf12 mutation causing mitochondrial membrane-protein Associated Neurodegeneration masquerading as spastic paraplegia.

Mitochondrial Membrane-protein Associated Neurodegeneration (MPAN) is a rare disease, caused by C19orf12 mutations and up to 29 different mutations have been described. We report a young woman presented with spastic paraparesis due to C19orf12 gene. MPAN presenting like Hereditary spastic paraplegia-43 is rare and the genetic mutation had been described only once in the literature.

Early Onset Degenerative Parkinsonism - Consider SPG7 Mutation.

A 43-year-old man presented with ataxia and stiffness of lower limbs for approximately last 10 years. The clinical examination revealed bilateral parkinsonism The magnetic resonance imaging of the brain and spine showed no structural abnormality to explain his symptoms. However, the dopamine transporter scan showed abnormal tracer uptake in both basal ganglia, suggestive of degenerative parkinsonism. The next generation sequencing of spastic paraparesis gene panel revealed probably pathogenic novel mutation in the SPG7 gene. Though the exact mechanism of parkinsonism in SPG 7 mutation is unclear, mitochondrial dysfunction and oxidative stress seem to play a key role. SPG7 mutation should be considered as a cause of early onset degenerative parkinsonism when no alternative explanation can be found.

Diaphragmatic paralysis resulting in respiratory failure as a feature of hepatitis E virus-associated neuralgic amyotrophy.

Hepatitis E virus (HEV)-associated neuralgic amyotrophy (NA) is often bilateral and severe, involving structures outside the brachial plexus, such as the phrenic nerves or the lumbosacral plexus. We report a case of an HEV-positive man who had presented with brachial neuritis, with significant phrenic nerve involvement, resulting in diaphragmatic paralysis requiring non-invasive ventilation. Prognosis of HEV-associated NA is often unfavourable and recovery is usually incomplete. Identifying HEV-associated NA early could potentially aid in prognostication and management planning, as clinicians and patients would be expectant of its potential features and severity. Respiratory function should be monitored in patients with HEV who suffer from NA, as diaphragmatic paralysis could potentially lead to severe respiration difficulties requiring ventilatory support.

Palatal Tremor - Pathophysiology, Clinical Features, Investigations, Management and Future Challenges.

Background: Palatal tremor is involuntary, rhythmic and oscillatory movement of the soft palate. Palatal tremor can be classified into three subtypes; essential, symptomatic and palatal tremor associated with progressive ataxia. Methods: A thorough Pubmed search was conducted to look for the original articles, reviews, letters to editor, case reports, and teaching neuroimages, with the keywords "essential", "symptomatic palatal tremor", "myoclonus", "ataxia", "hypertrophic", "olivary" and "degeneration". Results: Essential palatal tremor is due to contraction of the tensor veli palatini muscle, supplied by the 5th cranial nerve. Symptomatic palatal tremor occurs due to the contraction of the levator veli palatini muscle, supplied by the 9%th and 10%th cranial nerves. Essential palatal tremor is idiopathic, while symptomatic palatal tremor occurs due to infarction, bleed or tumor within the Guillain-Mollaret triangle. Progressive ataxia and palatal tremor can be familial or idiopathic. Symptomatic palatal tremor and sporadic progressive ataxia with palatal tremor show signal changes in inferior olive of medulla in magnetic resonance imaging. The treatment options available for essential palatal tremor are clonazepam, lamotrigine, sodium valproate, flunarizine and botulinum toxin. The treatment of symptomatic palatal tremor involves the treatment of the underlying cause. Discussion: Further studies are required to understand the cause and pathophysiology of Essential palatal tremor and progressive ataxia and palatal tremor. Similarly, the link between tauopathy and palatal tremor associated progressive ataxia needs to be explored further. Oscillopsia and progressive ataxia are more debilitating than palatal tremor and needs new treatment approaches.