Objective: To investigate the progression of cognitive impairment and its behavioral aspects in patients with SPG4-linked autosomal dominant hereditary spastic paraplegia (SPG4-ADHSP).
Methods: Sixteen patients, 45 years or older, from five families with SPG4-ADHSP were prospectively assessed. Eleven of these, from three families, were followed and 10 had two cognitive examinations using the Cambridge Cognitive Assessment (CAMCOG) 2.9 years apart. The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), the Neuropsychiatric Inventory (NPI), and the Nurses' Observation Scale for Geriatric Patients (NOSGER) were completed by close relatives of the 11 patients at the second assessment. Eleven matched control subjects had CAMCOG examinations 3.1 years apart.
Results: The mean CAMCOG score at the initial assessment was lower for the 10 HSP patients (73.5/107) than for 10 control subjects (91.7/107, p = 0.005). After 2.9 years, the HSP patients experienced a fall in the mean CAMCOG by 9.1 points to 64.4/107 (p = 0.008). The mean CAMCOG score for the control subjects (90.8/107) fell by only 0.9 points after 3.1 years (p = 0.36). The CAMCOG scores of two HSP patients moved from the mild (60 to 80) into the moderate dementia category (35 to 59) and in three other patients into the mild dementia range from borderline normal scores (81 to 85). IQCODE scores were abnormal in 9/11 HSP patients and 1/11 controls (p = 0.001). Seven of the 11 HSP patients were considered as having dementia.
Conclusion: This study indicates an active progression of cognitive deterioration and dementia in older patients with SPG4-ADHSP.