DC9 CAPT HAD ALT AND SPD DEV.

Narrative

FEARS OF A 'SENIOR MOMENT' LEAD TO A 'SENIOR MOMENT.' WHILE PREPARING THE COCKPIT FOR FLT; I WAS REPEATEDLY FORGETTING THINGS AND MAKING DUMB MISTAKES. I'M ALMOST 55 YRS OLD AND BEGAN WONDERING ABOUT LOSING MY ABILITIES; DUE TO AGE RELATED DETERIORATION. I WAS THINKING FEARFULLY ABOUT ALL THIS WHEN I BLEW RIGHT THROUGH MY ASSIGNED ALT OF 5000 FT. THE ALT ALERTER WARNED ME AT 5300 FT; I DID A HARD PUSHOVER AND RETURNED TO 5000 FT AFTER REACHING 5400 FT. THE REST OF THE FLT WAS NOT MUCH BETTER AS I COULD NOT GET MY MIND ON THE TASK AT HAND NO MATTER HOW I TRIED. THERE WERE MANY OCCASIONS WHEN I WAS LATE OR SLOW WITH SOMETHING. I MISSED A SPD RESTR; AND ALMOST MISSED 3 OTHER RESTRS. THROUGHOUT THE FLT; I KEPT DWELLING ON WHAT WAS CAUSING THIS TERRIBLE FLT AND THAT ACTUALLY WORSENED THE SIT. IN RETROSPECT; I DON'T KNOW IF THIS WAS A SERIES OF 'SENIOR MOMENTS;' OR SOMETHING ELSE; BUT IF I EVER DETECT THE ONSET OF THIS AGAIN; I WILL GND MYSELF IF PRIOR TO FLT; AND IF ALREADY AIRBORNE; GIVE IT TO THE FO.