Could a nasal spray of insulin help Parkinson's symptoms?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Subject has Idiopathic PD defined by the cardinal sign, bradykinesia, plus the presence of at least 1 of the following: resting tremor or rigidity and without any other known or suspected cause of Parkinsonism (according to Movement disorder society (MDS) clinical diagnostic criteria for Parkinson's disease confirmed by a fellowship trained movements disorder specialist * Subject is Hoehn \& Yahr stage less than or equal to 3 * Subject has a MOCA score ≥10. * Subject is \> 40 and \<90 years of age. * Female subjects are post-menopausal or have a negative pregnancy test * The subject must be proficient in speaking, reading and understanding English in order to comply with procedural testing of cognitive function, memory and physiology. * Subject has provided informed written consent prior to participation. In the event that subject is legally unable to provide informed written consent due to deterioration in cognitive abilities, fully informed written consent must be provided by a legally authorized representative. * Subject is on a stable dose (at least 1 month prior to baseline visit) of antiparkinsonian agents and is willing to remain on this dose for the duration of the study. If the subject is on a cholinesterase inhibitor, a stable dose without changes for 1 month is also required. * Subject has undergone a brain CT or MRI prior to the study as part of their previous diagnostic workup for PD to rule out underlying structural lesions, as determined clinically significant by the investigator Exclusion Criteria: * Subject has atypical Parkinson's syndrome(s) due to drugs (e.g., metoclopramide, neuroleptics), metabolic neurogenetic disorders (e.g., Wilson's Disease), encephalitis, cerebrovascular disease, or degenerative disease (e.g., Progressive Supranuclear Palsy, Multiple System Atrophy, Corticobasal Degeneration, Lewy Body dementia) * Subject has medical history and/or clinically determined disorders: chronic sinusitis, untreated thyroid disease, or significant head trauma. * Subject has history of any of the following: moderate to severe pulmonary disease, poorly controlled congestive heart failure, significant cardiovascular and/or cerebrovascular events within previous 6 months, condition known to affect absorption, distribution, metabolism, or excretion of drugs such as any hepatic, renal or gastrointestinal disease or any other clinically relevant abnormality that inclusion would pose a safety risk to the subject as determined by investigator. * Subject has had previous nasal and/or oto-pharyngeal surgery and severe deviated septum and/or other anomalies. * Subject has history of any psychiatric illness that would pose a safety risk to the subject as determined by investigator. * Subject is currently taking sedative medications that are clinically contraindicated as determined by investigator. * Subject has undergone a recent change (\<1 month) in their anti-parkinsonian medication, cholinesterase inhibitor or anti-depressant medication. * Subject has current or recent drug or alcohol abuse or dependence as defined by Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM-IV TR). * Screening laboratory results that are medically relevant, in which inclusion would pose a safety risk to the subject as determined by investigator. * Subject has participated in a clinical trial investigation within 3 months of this study. * Subject has an insulin allergy. * Subject has Insulin-dependent diabetes