Faculty Bibliography

Infectious diseases remain the most common cause of neurological disability in the world. A number of movement disorders can develop in adults and children in response to infections. These can occur in isolation or as part of a broader neurological illness, with movement abnormalities consequent to an encephalopathy or a broader brain dysfunction. While most infection-related movement disorders are direct consequences of an active infectious process affecting cerebral structures implied in the motor network, at times a delayed immune-mediated process in response to a previous infectious is responsible for the neurological dysfunction. This immunological response can occur as a consequence of a number of pathogens, and develop at variable times after the initial infection. The most common infection-mediated autoimmune movement disorders are chorea, which is especially common in children, and other hyperkinetic disorders, but Parkinsonism and other hypokinetic movement disorders may also occur.

Idiopathic normal pressure hydrocephalus (iNPH) is the most common cause of hydrocephalus in adults. The diagnosis may be challenging, requiring collaborative efforts between different specialists. According to the International Society for Hydrocephalus and Cerebrospinal Fluid Disorders, iNPH should be considered in the differential of any unexplained gait failure with insidious onset. Recognizing iNPH can be even more difficult in the presence of comorbid neurologic disorders. Among these, idiopathic Parkinson's disease (PD) is one of the major neurologic causes of gait dysfunction in the elderly. Both conditions have their peak prevalence between the 6th and the 7th decade. Importantly, postural instability and gait dysfunction are core clinical features in both iNPH and PD. Therefore, diagnosing iNPH where diagnostic criteria of PD have been met represents an additional clinical challenge. Here, we report a patient with parkinsonism initially consistent with PD who subsequently displayed rapidly progressive postural instability and gait dysfunction leading to the diagnosis of concomitant iNPH. In the following sections, we will review the clinical features of iNPH, as well as the overlapping and discriminating features when degenerative parkinsonism is in the differential diagnosis. Understanding and recognizing the potential for concomitant disease are critical when treating both conditions.

BACKGROUND: Parkinson's disease (PD) is predominantly recognized for its motor symptoms, but patients struggle from a morbid and heterogeneous collection of non-motor symptoms (NMS-PD) that can affect their quality of life even more. NMS-PD is a rather generalized term and the heterogeneity and non-specific nature of many symptoms poses a clinical challenge when a PD patient presents with non-motor complaints that may not be NMS-PD. CASE PRESENTATION: We report two patients with idiopathic PD who presented with acute episodes of cognitive changes. Structural brain images, cardiovascular and laboratory assessment were unremarkable. Both patients experienced a considerable delay before receiving an epilepsy-evaluation, at which point electroencephalogram abnormalities supported the diagnosis of focal non-motor seizures with alteration of awareness. Antiepileptic therapy was implemented and was effective in both cases. CONCLUSIONS: Diagnosing non-motor seizures can be challenging. However, PD patients pose an even greater challenge given their eclectic non-motor clinical manifestations and other disease-related complications that could confound and mislead adequate clinical interpretation. Our two cases provide examples of non-motor seizures that may mimic non-motor symptoms of PD. Treating physicians should always consider other possible causes of non-motor symptoms that may coexist in PD patients. Epilepsy work-up should be contemplated in the differential of acute changes in cognition, behavior, or alertness.

Freezing of gait (FOG) is 'an episodic inability to generate effective stepping in the absence of any known cause other than parkinsonism or high level gait disorders'. FOG is one of the most disabling symptoms in Parkinson's disease, especially in its more advanced stages. Early recognition is important as FOG is related to higher fall risk and poorer prognosis. Although specific treatments are still elusive, there have been recent advances in the development of new therapeutic approaches. The aim of this review is to present the latest knowledge regarding the phenomenology, pathogenesis, diagnostic assessment and conventional treatment of FOG in Parkinson's disease. A review of the evidence supporting noninvasive brain stimulation will follow to highlight the potential of these strategies.