The locked-in syndrome (LiS) is defined as the loss of most voluntary muscle movements with preserved cognitive abilities due to a ventral pontine lesion. However, some patients may also have severe impairment of consciousness [locked-in plus syndrome (LiPS)]. Here we aimed to explore structural differences between LiS and LiPS patients of vascular aetiology, focusing on lesion patterns and locations to better delineate the clinical spectrum of LiS and LiPS. In this retrospective case series study, we report nine patients (two women), ages 29-74 years (median 50) with LiS and LiPS who were diagnosed between 2007 and 2021. Clinical parameters, MRI findings including the lesioned structures, and a shape feature calculation are presented for every patient. The lesioned structures were determined by a senior neuroradiologist. Two of nine patients had fully retained consciousness (LiS) and seven showed various degrees of impaired consciousness (LiPS). Lesions of LiS patients are round and confined to the pons, whereas lesions of LiPS patients are more elongated and reach neighbouring areas such as the mesencephalon, thalamus or ascending reticular activating system. Lesions involving the mesencephalon and the thalamus are strong indicators of LiPS, whereas for lesions restricted to the pons, the dorsal extension and the associated damage to the ascending reticular activating system are crucial to differentiate LiS from LiPS. Recognizing LiPS using clinical and radiological findings is important as these patients may need different therapies and care and, most importantly, should not be mistaken as unresponsive wakefulness syndrome.
The locked-in syndrome (LiS) is characterized by quadriplegia with preserved vertical eye and eyelid movements and retained cognitive abilities. Subcategorization, aetiologies and the anatomical foundation of LiS are discussed. The damage of different structures in the pons, mesencephalon and thalamus are attributed to symptoms of classical, complete and incomplete LiS and the locked-in plus syndrome, which is characterized by additional impairments of consciousness, making the clinical distinction to other chronic disorders of consciousness at times difficult. Other differential diagnoses are cognitive motor dissociation (CMD) and akinetic mutism. Treatment options are reviewed and an early, interdisciplinary and aggressive approach, including the provision of psychological support and coping strategies is favoured. The establishment of communication is a main goal of rehabilitation. Finally, the quality of life of LiS patients and ethical implications are considered. While patients with LiS report a high quality of life and well-being, medical professionals and caregivers have largely pessimistic perceptions. The negative view on life with LiS must be overthought and the autonomy and dignity of LiS patients prioritized. Knowledge has to be disseminated, diagnostics accelerated and technical support system development promoted. More well-designed research but also more awareness of the needs of LiS patients and their perception as individual persons is needed to enable a life with LiS that is worth living.
