· Electrovestibulograpy (EVestG) is a diagnostic tool being applied towards the Classification, Severity measure, Drug Efficacy measure, Physical Treatment efficacy measure and Prediction of treatment efficacy in neurological and neurodegenerative disorders. EVestG is a recording of the vestibulo- acoustic activity from the ear canal (Lithgow, 2012). Diagnostic and therapeutic development for neurological and neurodegenerative disorders: (Examples using EVestG) o The identification of Depression type (the depressive phase of Bipolar Disorder (BD) versus Major Depressive Disorder (MDD)) is challenging at first clinical visit and is often wrong especially in Bipolar Type II wherein an obvious Manic phase may not have presented yet. The figure shows the identification of Bipolar and Major Depression at baseline using EVestG measures. (Lithgow et. al., 2019) o Being able to detect Post Concussion Syndrome (PCS) is difficult particularly long term PCS. This is made more difficult when Depression is a comorbidity. Opposite is the identification of PCS patients with and without comorbid depression versus healthy controls when using EVestG measures. (Suleiman et. al, 2018) o Identifying Dementia (sub) types; Dementia often occurs with vascular disease. One form of Dementia is Vascular Dementia. The most common dementia, Alzheimer’s Disease, often occurs with comorbidities such as cerebrovascular symptomatologies and is termed Mixed Dementia (ADcvd) . It is important to be able to identify ADcvd that best treatment/therapy may be applied. (Lithgow et al., 2021) Predicting which Alzheimer patients will benefit from repetative transcranial magnet stimulation (rTMS) treatment. rTMS is an expensive and lengthy magnetic therapy applied to improve cognition in Alzheimer patients. Only about half benefit from rTMS so selecting only those who will likely benefit means the others can be given alternate treatments better suited to their individual condition. (Lithgow et al. 2022, In Press). Modelling of vestibular electro-neurophysiology. Understanding the pathophysiology behind the measures being applied to measure the eficacy of a treatment is vital. Modelling the neurological response is one way to improve that understanding.