ABSTRACT Whiplash associated disorders (WAD) is one of the most debated musculoskeletal conditions. Sensory disturbances including hypersensitive responses to mechanical, thermal and electrical stimulation have been consistently shown to be a feature of both the acute and chronic stages of the whiplash condition. More importantly, such dysfunctions have also been found to be associated with higher risk of poor functional recovery. It is apparent that better understanding of the sensory disturbances in WAD is needed in order to elucidate mechanisms underlying the pain and disability of this recalcitrant condition and to facilitate the development of more effective management strategies. Comprehensive Quantitative Sensory Testing (QST) combining sensory detection and pain threshold measures is proving to be a valuable tool to advance the classification and illuminating the underlying mechanisms of an array of musculoskeletal pain disorders but such protocol has never been undertaken in a WAD cohort. In order to fill this gap in knowledge, the series of studies in the thesis aimed to utilize comprehensive QST to investigate the presence of somatosensory dysfunction in chronic WAD and to compare the somatosensory profile of WAD to cervical radiculopathy and idiopathic (non-traumatic) neck pain. Once a better understanding of the potential underlying mechanisms in chronic WAD was established, the research then focused on documenting the presence of such somatosensory disturbances soon after whiplash injury and its temporal development over a 6 months period. The results have provided a number of significant insights into some of the potential underlying mechanisms of the somatosensory dysfunction in WAD as well as other neck pain conditions of different aetiology. It is clear that generalised sensory hypoaesthesia coexisted with sensory hypersensitivity in chronic WAD and a combination of pain and detection measures best discriminated patients with WAD and controls. Similar sensory presentation was also found in patients with cervical radiculopathy but not in idiopathic neck pain patients. This finding indicates that different mechanisms underlie various musculoskeletal conditions with disordered central processes contributing to a greater degree in some conditions. Patients with whiplash and those with cervical radiculopthy may share similar underlying pain mechanisms involving the central nervous system and the discrepant findings in the idiopathic neck pain group may be due to the magnitude of nociceptive input required to induce/maintain altered central adaptive changes. Another important observation from the studies was that sensory hypoaesthesia was present in the majority of patients with whiplash injury in the acute stage. However, it persisted only in individuals who initially reported higher levels of pain and disability levels and sign of hypersensitivity. It was this group of individuals who predominantly developed persistent symptoms at six months post injury. The longitudinal findings indicate that such sensory impairments can be identified very early on and treatment interventions directed at these sensory disturbances (both sensory hypersensitivity and hypoaesthesia) should aim to reduce the nociceptive input and this may improve recovery post whiplash injury. The findings in this thesis demonstrated the clear association between sensory hypersensitivity and other sensory disturbances and their potential influence on recovery. Furthermore, the heterogeneity of the whiplash condition highlighted the importance of the early identification of “low-risk and “high-risk” patients in order to assist the clinicians to make clinical decisions on the best management approach. It cannot be overemphasised that the early assessment of whiplash injured patients should aim to identify features associated with poor recovery and a better classification system will be an important step. Implications for assessment and management of whiplash are vital in the acute stage of injury and may well go some way toward preventing the transition to chronicity, particularly in those with a more complex clinical presentation involving somatosensory disturbances. Further research directions have also been identified in order to improvement management of this complex clinical condition.