Rock legend Ozzy Osbourne has died at the age of 76, six years after receiving a Parkinson's disease diagnosis in 2019.

The Black Sabbath frontman's neurological journey began over a decade earlier when doctors identified Parkinsonian syndrome in 2007.

The 2019 diagnosis marked a progression from his earlier condition, with Osbourne disclosing his health struggles in 2020, when he revealed the full extent of his battle with the degenerative neurological disorder.

The revelation helped explain his reduced public appearances and the physical challenges he had been facing throughout the late 2010s.

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Initially, the musician believed his trembling hands resulted from decades of hard living, but medical examinations revealed a more serious underlying condition when he received the Parkinsonian syndrome diagnosis in 2007.

The health complications intensified following a nocturnal tumble in 2019 that damaged his spine, worsening previous injuries from an earlier quad-bike incident.

Despite multiple surgical interventions, the procedures achieved only partial improvements. The combination of neurological symptoms and spinal trauma created mounting physical difficulties that would ultimately influence his career decisions.

Eventually, the spinal injuries and Parkinson's symptoms ultimately forced Osbourne to withdraw from live performances.

How is Parkinson's diagnosed?

Medical professionals diagnose Parkinson's through specific clinical criteria established over two centuries of research.

The condition requires the presence of bradykinesia - slowness of movement - alongside either tremor or muscle rigidity.

Persistent loss of smell, clinically known as hyposmia, is observed in 70 to 90 per cent of individuals with Parkinson's, often years before the onset of motor symptoms like tremor or rigidity.

A report published in the Neuroscience Bulletin in 2017 stated that Olfactory dysfunction (reduced or lost sense of smell) is one of the most common and best-characterised non-motor features in Parkinson's Disease, with a prevalence of 50 per cent to 90 per cent. The findings have since been reaffirmed in several medical journals.

"Hyposmia is often one of the first manifestations of the disease," authors wrote in their report.

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James Parkinson first documented the disease in 1817, describing characteristic symptoms including shaking, bent posture, and shuffling walk.

Modern diagnostic standards, developed by institutions like Queen Square Brain Bank, emphasise asymmetric symptom onset and positive response to levodopa medication.

Early warning signs can emerge years before motor symptoms, including loss of smell, constipation, mood changes, and sleep disturbances.

Specialists now achieve approximately 90 per cent diagnostic accuracy through clinical assessment combined with patient history.