Heterogeneity of persisting symptoms after sport-related concussion (SRC): exploring symptom subtypes and patient subgroups.

This study aimed to explore the heterogeneity of persisting symptoms after sport-related concussion (SRC). We examined the structure of symptom subtypes within 163 patients with SRC (M = 16.7 weeks post-injury). Subsequently, we investigated the existence of subgroups of patients based on comparable configuration of co-occurring symptom subtypes. To explore factors that may contribute to the emergence of SRC patient subgroups, subgroups were compared on pre-injury (i.e., demographics and medical history), personality (Severity Indices of Personality Problems Short Form) and SRC characteristics (i.e., history of prior concussions, loss of consciousness and post-traumatic amnesia). To investigate the relevance of SRC subgrouping for clinical outcome, subgroups were compared on symptom severity (Sport Concussion Assessment Tool 5). The results provide empirical evidence for the existence of symptom subtypes, characterized as a: neurocognitive, fatigue, emotional, migraine and vestibular-ocular symptom subtype in patients with persisting SRC. Study results also showed evidence for the existence of SRC subgroups of patients with a comparable configuration of co-occurring prevailing symptom subtypes, including a neurocognitive-migraine, fatigue, migraine-emotional and neurocognitive-emotional subgroup. The subgroups differed on pre-injury, personality and SRC characteristics, suggesting that these factors may contribute to the emergence of specific SRC patient subgroups. The subgroups also differed in the severity of persisting symptoms, highlighting the clinical relevance of SRC subgrouping. These results support the idea that patient subgroups with persisting SRC with a comparable pattern of co-occurring symptom subtypes exists, which may require targeted prognosis, clinical management and treatment to optimize recovery.