認知症の症状，特に BPSD は罹患した本人のみならずその家族や周りの人の生活，QOL にも影響を与える．BPSD は中核症状と環境要因，身体要因，心理要因などの相互作用によって起こることが多く症状の軽重には個人差もあることからその発症予測は難しい．BPSD 発症に関わる神経基盤の理解とその発症リスク予測につながる客観的な指標の確立のための探索的検討として， BPSD の発症と脳の構造的変化との関連を検討する目的で，MRI データにおける大脳皮質の局所容積変化を BPSD 発症の有無で比較し，BPSD 発症に関連する脳領域の検討を行った．川崎医科大学附属病院脳神経内科ものわすれ外来を受診した患者20名（平均74.8歳，男性５名）を対象に年齢，性別，認知機能（MMSE-J，FAB），うつ（GDS-15-J），BPSD の程度（阿倍式 BPSD スコア： ABS）を用い，BPSD の有無（ABS：０vs１以上）によって患者を２群に分け患者背景，臨床指標評価を比較した．また同時期に測定した MRI 3DT1画像データを使用し，SPM12ソフトウェアを用いて患者の灰白質，白質，脳脊髄液領域を分離し，解剖学的標準化を行って灰白質容積の群間差を検討した．結果，年齢，性別，MMSE，FAB，GDS は両群間で有意差を認めなかった．灰白質容積の群間差の検討では，BPSD あり群では右中前頭回（BA6），右下前頭回三角部（BA45）の灰白質容積が有意に低下していた．BA6と BA45における ABS と灰白質容積にはそれぞれ負の相関があった．認知症患者の BPSD 発症が右前頭葉皮質の灰白質容積低下が関連している可能性が示唆された．先行研究により BA6は他者の意図を推察する心の理論課題に関与し，BA45の灰白質容積の低下は統合失調症患者における妄想や陽性症状との相関が示唆されている．今後 BPSD の発症予測や個別治療の可能性につながる重要な知見と考えられ，今後の研究の進展が期待される． Symptoms of dementia, especially Behavioral and Psychological Symptom of Dementia (BPSD), affect the quality of life of not only patients but also family members and caregivers. Underlying mechanisms of BPSD is still unknown but multiple factors including cognitive impairments as well as environmental, physical, and psychological factors may cause BPSD and the severity of symptoms varies individually. In this study, we aimed to investigate the underlying neural mechanisms for emerging BPSD by comparing the regional volume change of the cerebral cortex in patients with or without BPSD to identify the cortical region critical for emerging BPSD. We evaluated 20 patients (average age 74.8, M5) who visited our memory clinic for their age, gender, cognitive function (MMSE-J, FAB), depression (GDS-15-J), and BPSD (ABS) degree. We divided patients into two groups according to the presence of BPSD (ABS: 0 vs 1 or higher) and background characteristics and clinical indicators were compared. Using 3DT1 image data acquired by 3-Tesla MRI apparatus, we segmented the patient’s brain into gray matter, white matter, and cerebrospinal fluid. After anatomical normalization, we conducted group-wise comparison between patients with and without BPSD to investigate cortical area associated with emerging BPSD. Patients’characteristics and baseline cognitive factiors including Age, sex, MMSE-J, FAB, and GDS-15-J showed no significant difference between the two groups. The gray matter volume of the right middle frontal gyrus (BA6) and the right lower frontal gyrus triangle (BA45) were significantly reduced in the patients with BPSD. Furthermore, in BA6 and BA45, there were negative correlation between severity of BPSD and gray matter volumes suggesting possible association between gray matter volume in the right frontal cortex and BPSD. Previous studies have shown that BA6 is associated with the Theory of Mind, and that a decrease in the gray matter volume of BA45 is correlated with delusions and positive symptoms in patients with schizophrenia. This is an important finding that leads to the prediction of the onset of BPSD and the possibility of individual treatment
